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The Cold Hard Facts of Freezing to Death (1997) (outsideonline.com)
437 points by BlackJack 1667 days ago | hide | past | web | 184 comments | favorite

Living in Michigan, this is one of my biggest fears. Due to the massive lakes that surround us, we frequently get a blast of warm, wet air that causes rain, and of course that warm wet air is being pushed off the lake by a cold front, causing high winds and sub-freezing temps. This combined with large stands of farmland and no trees for windrows means wind blows right across the road and freezes the rain instantly, sometimes right beneath your tires. What was wet a second ago is now frozen, and you can't see the difference. The snow starts to pile up, and a gust of wind pushes you right off the road and into an irrigation ditch. The best 4x4 in the world won't get you out now. And good luck using your cell phone: the areas where this is most likely to happen often have no cell service, or the cell service is only for Verizon phones (too bad you have AT&T, and the FCC forced them to sell off their overlapping network in that area). Four wheel drive won't help. Locking differentials won't help. All wheel drive won't help. All of these require even faintest bit of traction, and you don't have it.

People think I'm weird for having a CB radio in my truck, but last winter during an ice storm I went off the road. Literally all of the county's emergency crews were busy taking care of other ditch parties. I called out on my CB for the local off-roading enthusiasts, and 15 minutes later a snowmobile arrived with a winch. I paid $30 to the man for his help (though he insisted he didn't need payment), and I was back on the road. The CB cost me $250; how much would a tow truck have cost?

This article should be read by everyone who has to travel in winter conditions. Seems like every winter I hear the obituary on the news of people who go off the road and try to hoof it somewhere miles away in a normal winter jacket, jeans, and boots. I keep a snowmobile suit in my truck during the winter. One thing I would have added is something along the lines of "and you knew you couldn't stay in your car with the heat running waiting for help, you'd die from the exhaust fumes". I think that's more common than freezing to death.

Why would you die from fumes inside your car? Provided the air intakes and exhaust pipe were clear of snow, I was under the impression it wouldn't really build up.

Assuming the exhaust pipe is clear isn't the best assumption when you're in a ditch in the middle of a blizzard. Even if the pipe is clear, rust from the all the salt on the road or damage from going into the ditch could easily put a hole in your exhaust.

So what is the best play then? Wait in the car without the engine running?

Might not be that bad, there was a case here in Sweden last winter with a man that got trapped in his car for 60 days, with temperatures reaching -28 C.

He apparently survived by eating some snow (and drinking some soda?) but had nothing else to eat. He had a sleeping bag and I guess the snow makes quite good isolation. Not something I'd recommend though, he was lucky to survive and was in a really bad shape when he was found.

( some pictures: http://www.aftonbladet.se/nyheter/article14394731.ab )

I've slept in a car (a VW bus with the seats down to make a flat space) without the heater running, in below-freezing conditions (maybe 10-15 degF) with another person.

It was actually pretty amazing how well it worked. We had sleeping bags, but woke up to find the interior of the car quite warm. It actually seemed downright cozy and luxurious compared to sleeping in mountain lodges where it's typically miserably cold in the sleeping areas outside your sleeping bag.

My takeaway: this experience seems to suggest that a few people in a small space that's wind-tight and maybe has a bit of insulation (clearly not great in a car with all that glass) can keep things reasonably warm with only body heat...

About.com (not the best resource, but I googled the answer since I don't know it) recommends running your engine for short periods and cracking the window open.

I'm hesitant to actually agree, since cracking the window open doesn't seem like an awesome idea in the middle of a blizzard but... eh.


Cracking your window open during a blizzard wouldn't be too bad. Blizzards mean snow and it typically stops snowing when it gets substantially cold, so it is very likely that the heat from your engine would over power the slight cool air coming in from the window.

Not sure, do cars reliably start in the cold?

They do. I've personally never had a problem starting my engine, even in -40 (Celcius) nights in Canada. It sure takes a couple of seconds, but recent cars (>1990) all start just fine in extreme cold. Given your battery is charged, and your engine is in normal conditions.

Interesting tidbit: -40 Celsius is the exact same temperature as -40 Fahrenheit.

Nitpick: If you have a diesel, your car will not start at all if the engine is cold, but if you have a diesel and live anywhere where there's a risk of it being cold enough for hypothermia, you already know this. Also if you have a crappy battery, in cold enough weather it won't put out enough juice to turn over the starting motor (that's why there is a difference between cranking amps and cold cranking amps). But again, if you live in an area where this is an issue you should already know this, and your battery is probably rated to like -40.

The problem of course is that diesel fuel goes thick and viscous at very low temperatures.

I discovered this last winter when it got to -15 here in the UK - I was waiting for a diesel train from our local station that was 20 minutes late as they couldn't get it started.

It was interesting seeing electric trains too - the pantographs gave off amazing blue sparks that you normally don't get when the weather is warmer.

Are engine block heaters common there? It was 10°F last night where I live (in the US) and they are pretty common here.

Keeping the exhaust clear would be worthwhile even if it means going out in the snow and doing some work. You should be doing that anyway: your best chance of being found is brushing most of the snow off the top of the vehicle so someone passing by or overhead is sure to see it.

The exhaust will clear itself if it's only snow. It's quite hot and will melt the snow very fast.

I tend to agree that the person I was responding to was probably exaggerating the risk, although if you've just spun the car into a field, it's buried in deep snow, and you've got a known leaky exhaust, it couldn't hurt. The "leaky exhaust" part is tricky: I had a friend once whose car's exhaust (and everything else) was so rusty you wouldn't want to sit in it when it was stationary. It was almost comically dangerous the way the car would fill with exhaust smoke.

The value of getting out and clearing the top of the car is very great regardless. A vehicle is much more recognizable as a vehicle when it's not covered with snow.

The conditions you describe are tough. Going off the road in an ice storm sucks. Love your CB and snow suit suggestions.

The following is not commentary on your situation, but tips to reduce chance of getting stuck:

1. I strongly recommend running a set of good snow tires, no matter whether you have an AWD Subaru or a 4x4 truck or a FWD Corolla. Yes, truck snow tires exist.

The reason is that the rubber compound is much much softer on these tires, and it stays soft when the temperatures drop. All-season tires are much harder in cold temperatures. The tread is also cut into much smaller blocks (known as siping), the edges of which help bite into the ice.

While ice is slippery no matter what, the difference in the grip level between a typical all season tire and a good snow tire is very significant. We are talking 3x the stopping distance. I've seen it on glare ice.

Now, if you really want to be protected, you must buy good studded snow tires. A set of Nokian Hakkapeliitta 7's will make ice seem almost like wet pavement. The amount of ice grip you have with those is unbelievable. The downside is the increased tire noise.

2. Practice controlling skids on ice or snow: practice countersteer, practice NOT hitting the brakes, practice using throttle.

If you can practice this to make it second nature, or at least not foreign, this can make the difference between you spinning and not.

Get out to a snowy parking lot, start turning, let off throttle, then yank the e-brake (and put it down right away). You should start experiencing a spin at this point. No matter what, train yourself to immediately countersteer, such that your front wheels are pointed to where you want the car to go and not where the car is facing.

Now, while countersteering every time, compare the following 3 situations after starting the spin:

A. Counterseteer & do nothing with brake or gas. Simply get your feet off the pedals.

B. Countersteer & hit the brakes.

C. Countersteer & apply gas.

You must actually experience each of these to believe it, but you will learn that it is "C", applying gas, which will get you back in line the soonest. You will notice that as soon as you give it gas, the spin will stop or slow down significantly. You will notice that if you hit the brakes, you spin much further than if you were to simply let go off all the controls.

This is counter-intuitive, but basically if you start spinning on ice on a straight road and you have a FWD/AWD car, applying some throttle will often stop your spin, whereas hitting the brakes almost guarantees a spin. It's worth practicing, if you can.

The reason has to do with weight transfer. Your car's traction at each end is determined by the amount of weight. When you accelerate, you decrease traction up front and you increase traction in the rear. Lifting off throttle increases front end traction and decreases rear end traction, a little. Hitting the brakes massively decreases rear end traction and massively increases front end bite.

For truck snow tires, many times "reasonable" MT (mud terrain) or AT (all terrain) tires are also rated for snow. I say reasonable because MTs can get pretty extreme in their tread pattern, which will really hurt your stopping distance on ice. Extreme MTs have very little rubber touching the road. On my truck I have Goodyear Wrangler SilentArmor tires, which are rated for on/off-road and extreme snow. I wouldn't recommend them as street tires, as they are loud and wear very quickly on pavement, but just as an example of truck "snow" tires, ATs and MTs often serve the same purpose as snow tires, as well as giving you a better ability to get back on the road if you've gone off in a muddy or rough area.

ATs wear quicker than all-seasons (~50,000 miles). MTs wear extremely quickly (~30,000 miles). Normal all-season tires generally wear at ~60,000 miles.

-edit- also, before buying studded tires, check to see if they're legal in your state/country, and make a note of the legality dates. Many times they're only legal from November through March (studded tires damage the road when the road is dry). Tire chains are temporary solutions, but are practically illegal in many states (can only be used if the chain never touches the road surface).

I had a spit-take when you suggested 30k was extremely quick wear, as I'm used to motorcycle tyres, where 5k is a fairly long life!

Every year, as the snow hits, I "play" with the kids in the car in controlled circumstances. The points is to 1) re-awaken my skills and 2) give me a teaching opportunity with my kids. Dealing with an out of control situation in the ice is challenging enough when you are prepared. If you are constantly freaked out about the snow/ice, you are in big trouble when something unexpected happens.

It's also a lot of fun to deal with a car that is borderline out of control in a more controlled environment.

> you will learn that it is "C", applying gas, which will get

> you back in line the soonest. You will notice that as soon

> as you give it gas, the spin will stop or slow down

> significantly.

That only helps with more common, oversteer situations (when the rear wheels are skidding). On the contrary, if you're experiencing an understeer (front wheels are skidding) applying more gas will only make matters worse. You want the front wheels to regain traction, and there are two ways to do so- countersteering and do nothing with accelerator. A tiny little bit of braking may be neccessary.

All this advice is rarely useful when driving a car (except in places where temperature is below freezing point) but it's extremely important when riding a motorcycle on every kind of terrain.

> A tiny little bit of braking may be neccessary.

While it's true that braking can be very helpful, I'd caution against suggesting it because braking during a slide, even while it's understeer caused, can be very delicate and easy to overdo. And releasing the gas will quite often normalize the difference quite fast enough.

> The reason has to do with weight transfer. Your car's traction at each end is determined by the amount of weight. When you accelerate, you decrease traction up front and you increase traction in the rear. Lifting off throttle increases front end traction and decreases rear end traction, a little. Hitting the brakes massively decreases rear end traction and massively increases front end bite.

While this contributes to the effect, it's does not properly represent what's actually going on. Generally speaking, you want to perform action that normalizes the speed of the tires and the wheels, as you said, this is basically never breaking because wheels are good at slowing themselves down. If the slide is caused by slow tires, or if the tires have time to slow while the slide is happening (The most common case, and also the one that is caused by hitting the e-brake) Then indeed, as you said applying gas is the proper action. But compare this to a slide caused by wheel-spin due to too much gas, Any additional application of gas will just make the problem worse.

Having said that, if you do find yourself in a slide caused by too much gas, hitting the brakes will almost always make it worse, instead lightening up on the gas, and then slowly reapplying tends to be the most effective strategy.

The recommendation to use snow tires on cars/trucks in these areas seems to me like a given. In Sweden it's mandatory to have "winter tires" (either studded or non-studded, but rated for snow - if you're not in the southern-most parts of Sweden, where there's actually rarely snow more than a couple of weeks per year, I'd say 90%+ have studded tires) - given the (I believe?) similar winter climate, I would have believed that even if it had not been mandated it would be common knowledge to use these tires in winter climate? How common is it to use winter rated tires in the northern parts of the US? Also, in order to get a drivers license here you need to complete a "winter driving course" (which you do in the summer using a contraption on the car that raises it somewhat, reducing the grip of the tires - it's a pretty good estimate on driving on an icy road) - is there a similar requirement to pass for a drivers license in the states where the road conditions are similar?

Edmunds did a quantitative test of snow tire performance for one common FWD car.


Get a winch?

I've actually been saving up for a winch. I'd need to get a new bumper to hold a winch though, or mount a hitch to the front end.

Get a hand operated winch you can sling around a tree at the top of the ditch, rather than being permanently anchored to the car? Bonus, it can live inside the car and it won't get dinged in the crash.

Bumper-mounted winches being used with a proper winch bumper won't take damage in a crash either; if they do, you're likely not driving away from the crash so easy retrieval is unimportant. Off-road and winch bumpers are not designed with crumple zones in mind, they're mounted directly to the frame and the winch itself is tucked behind a 3/16th steel plate and steel tubing surrounding it.

With a front-mounted hitch, though, you can keep the winch inside and just hook it to either the front or the back depending on the needs. The downside is there's one more thing in your car taking up space and becoming a projectile in a crash.

Come-alongs (hand winches) are less than ideal for many reasons I've listed in another reply to your comment. The better solution is to do your best to not need one.

Get one of these:





It's only $15 for the cheapest one (they have other types too that mount to the car). Also get a long strap to go with it in case the nearest tree is not close.

You don't want an electric winch anyway - you never know if you'll have power in an emergency.

Having used come-a-longs and hi-lifts as come-a-longs, I would never wish that agony on anyone else. It's better than nothing, but far worse than an electric winch by a long shot.

Generally speaking, if the engine can't start/run, and help is nowhere to be found, winching the vehicle out will be more trouble than its worth. The best part of an electric winch is you may use it in conjunction with the engine when solo, meaning you can generally free the vehicle as soon as you find some traction, rather than constantly advancing, re-entering the vehicle and checking for traction again.

But you're right about and additional strap: one should always have with their winch, at a minimum, a tow strap and a tree saver (plus requisite shackles, snatch blocks, and gloves if using wire rope, or rock guards with synthetic). I once got stuck deep in a ravine, and 150' of synthetic rope fell short of the nearest tree by 5 feet, but a tow strap and tree saver made up the difference and I got to sleep in my bed that night, rather than in the jeep.

I've owned an 8000lb come-along in the past. Pulling my truck from the mud, the cable came off the pulley. I replaced it with a new come-along from a different brand, and again the cable hopped the pulley. This damages the pulley and bends the axle, rendering the winch useless. They're less than ideal for vehicle retrieval, especially if doing intense labor is not a great idea (like when you're at risk of hypothermia). Pulling a stuck car with a come-along is a very laborious and time-consuming task.

There are wheel-mounted winch pullers that are much better suited for the task, since they don't require standing out in the cold or as much physical effort.


That looks really cool, but $1000 for it is insane! It's a small metal drum and some cable.

> no cell service, or the cell service is only for Verizon phones

I remember reading somewhere that emergency calls can use any network.

The Verizon network is CDMA, which is incompatible with most other phones (GSM).

If you have a phone you can make an emergency call from it as long as there is service. The different networks have different frequencies and if your phone doesn't have the antenna its not going to work. This is more than just CDMA vs. GSM, although not sure about GPRS.

I was a big fan of the Android phones that had AM/FM radios awhile back. At least you'd be able to hear broadcasts to have a general idea of where the storm is heading. I grabbed one of those survival kits that have matches, a knife, first aid, etc.

Most Android phones can receive AM/FM radio using the Bluetooth antenna with a custom ROM that enables that functionality. Most common ROMs include it. Dedicated antennae for that purpose are rare but that's no reason to go without.

Samsung phones (at least SGS and SGS2) have FM radio functionality, but it only works with earphones plugged as they serve as the antenna.

I am pretty sure that one of my older phones used the headphones as an antenna?

Again, my Galaxy Nexus doesn't seem to have this functionality, although that's merely me trying to locate the pre-baked application and not finding it. So you're probably right about the ISV not including it.

My last two HTC Android phones had this functionality (the Desire and now the One S). Never used it, but this would be a situation where it could be handy. Although if you're in a car, the car radio probably has better reception.

I had previous Windows Mobile phones (Motorola Q and an HTC Touch Pro) that would pick up AM/FM radio so long as headphones were plugged in. I think my Samsung Focus was able to do it as well.

A dedicated radio (one with a hand crank) is better, much longer life and not too expensive just to leave in the car's emergency pack. Hand cranked LED isn't bad either.

While emergency calls must be routed even if you don't subscribe to a plan with the carrier of your phone, I'm not sure it would get through if you only have a GSM radio in your phone and the only tower nearby is a CDMA tower. Someone might correct me on that. Regardless, it will keep you from calling someone nearby that may be able to help without needing to call for emergency services.

Often, in a blizzard, the cell towers fail.

On a side not, at home, the local phone company tends to be pretty good at keeping the line going even when power fails. Last time, I got stuck 20 hours without power, the phone line worked the whole time. The cell towers did not.

If I lived in a non-urban area, I'd probably keep an Iridium handsets in my car again. $500 or so for a used one, and you can get cheap plans.

A CB will do just fine and be able to reach people who might be able to help you.

Have you considered carrying an EPIRB too?

This bit about how certain groups of people have somehow developed different responses to cold is fascinating:

Were you a Norwegian fisherman or Inuit hunter, both of whom frequently work gloveless in the cold, your chilled hands would open their surface capillaries periodically to allow surges of warm blood to pass into them and maintain their flexibility. This phenomenon, known as the hunter's response, can elevate a 35-degree skin temperature to 50 degrees within seven or eight minutes.

Other human adaptations to the cold are more mysterious. Tibetan Buddhist monks can raise the skin temperature of their hands and feet by 15 degrees through meditation. Australian aborigines, who once slept on the ground, unclothed, on near-freezing nights, would slip into a light hypothermic state, suppressing shivering until the rising sun rewarmed them.

You have no such defenses, having spent your days at a keyboard in a climate-controlled office. Only after about ten minutes of hard climbing, as your body temperature rises, does blood start seeping back into your fingers. Sweat trickles down your sternum and spine.

I saw a talk from a US Army-funded researchers on cold weather adaptation. He described how to reliably train oneself to induce the "hunter's response".

You just go sit outside in the cold for five or ten minutes at a time while keeping your hands and/or feet submerged in insulated warm water. The goal is to expose most of your body to the cold while keeping the capillaries open. After about fifty repetitions of this (at three to six repetitions per day), your body gets used to the idea of maintaining circulation despite an overall cold environment.

As someone who does a lot of mountaineering, I'd be inclined to use this technique for my hands. But I'm a bit scared about risking to become hypothermic earlier. And I guess I would prefer to loos my toes then becoming severely hypothermic.

Though, I have recommended this technique several times to some female with very severe "cold hand" problems.

Btw: I think I've seen the same talk at MITOC Winter School. I forgot the name of the speaker but he was a great guy. (Quote: "If you can't bend them - that's a bad sign.") I think he speaks at MITOC every year.

His name is Dr Murray Hamlet.

You can notice this effect in your life as well. I don't know where you live, but I know here in the north, 40F is "freezing" cold in November for many people. And when March rolls around, 40F is cause for breaking out the t-shirts. Your body will adapt to the cold to a certain degree. I think I saw it explained on a reddit "ask science" post some time ago, but I cannot remember the physiological details of these temporary adaptations to climate patterns.

I wonder if it's physical or at least partially psychological.

I live in Los Angeles and my brother lives in Flagstaff. Every year at the holidays, I go spend a week with him and his family. In Flagstaff there can be entire days below freezing and the nights can easily reach single digits F. When I'm there and it's 25 F, I'm fine. Toodle along like normal. Come back to LA and it's 50 and I shiver. Same outfits even. It's the strangest thing.

Maybe altitude? FLG is 7000 ft and LAX is more or less sea level. I dunno.

Could it be the humidity? Wet air usually feels colder.

True, but the humidity in November is usually lower than that of March... in the NE US anyway.

I had the same experience while in SF this fall. The temperature reading rarely dipped below 50, but the evenings felt brutally cold. When I returned to the east coast, temperatures 5-10 degrees below those in SF felt warm and cozy.

Extreme example: http://en.wikipedia.org/wiki/Wim_Hof (climbed Kilimanjaro, completed a marathon above the Polar circle, attempted to climb Everest, all dressed in nothing but shorts; claims that Tibetan meditation helps him)

Oh, wow - I had no idea! Thanks for pointing this out.

The scientific experiments with him are published now.

Kox et al, 2011 The Influence of Concentration/Meditation on Autonomic Nervous System Activity and the Innate Immune Response: A Case Study in Psychosomatic Medicine


Here is a trick I learned biking around in cold Las Vegas nights to warm your hands. Squeeze whatever you are holding hard, (or make a fist and squueze) in pulses about a second apart. It will force the blood through, like a miniature heart, and your hands won't feel cold at all.

Another trick that I learned from my ski team was to do arm circles. The centripetal force forces blood into your extremities.

Even better, keep your arms on the side of your trunk, your elbows straight and flex your hands at 90 deg so they point away sideways. Now, move your shoulders up and down. Don't use any other joints. Each down move of the shoulder will pump blood into your hands with high pressure.

We call it the penguin dance.

That is an old trick while donating blood. It is good to see that it has alternative uses. Never thought of it that way.

there's been some research into the Buddhist monk core/skin temperature regulation. apparently, you can train yourself to do this by using biofeedback, take a digital thermometer and a few hours a day and you can figure out how to raise your body temperature (I know people that have demonstrated this ability).

This is a somewhat common phenomenon in the martial arts that practice Tai Chi/qigong/reki

I used to teach a martial art that practiced this. In our meditation, you visualize glowing energy flowing through your body into your hands. After several months, it happens fairly naturally. Among more experienced practitioners, the skin temperature difference is very noticeable.

When we practiced this, we conflated it with hitting harder, which anecdotally seems to be true, but I'm not sure why.

My teacher claimed that doing the meditation and slowly working your way up to hitting harder materials would increase bone density in your hands, though I have no proof of this.

I'd love to see more western science studying these phenomenon.

This topic makes me think of the Jack London story "To Build a Fire", which is one of my favorites. http://www.jacklondons.net/buildafire.html

Also timely, one of our power users at Referly just made a preparedness kit list for winter driving. I probably should have had some of this when driving alone in the Sierra Nevadas last month. http://refer.ly/winter_driving_preparedness_kit/c/789d5ae050...

This topic makes me think of 2012 American adventure drama film co-written and directed by Joe Carnahan and starring Liam Neeson, Frank Grillo, and Dermot Mulroney "The Grey", which is based on the short story Ghost Walker by Ian MacKenzie Jeffers, who also co-wrote the screenplay with Carnahan.


My thoughts exactly

I carry a PLB at all times in my vehicle [1]. In the US this device will summon rescue via satellite. I recommend it for anyone who spends time in remote areas. If you value your life at $1MM and there's a 1 in 3500 chance [2] that summoning emergency services in a remote area will save your life then this is a helpful risk-mitigating tool [3].

1. http://www.amazon.com/ACR-Electronics-ResQLink-Personal-Loca...

2. $280 / $1MM ~ 1/3500.

3. A useful metric might be 911 calls, of which there are 240 million in 2008[4], for the US population of 305 million. If you assume 5% of the calls are life-or-death, that your daily odds of needing to call in remote areas are the same as the country mean, that you spend 5 days a year in remote areas, and a 5-year useful life for the device, then there is a 0.2% chance the device will save your life.

240/310 * .05 * 5/365 * 5 ~ 0.002

4. http://www.911dispatch.com/info/fact_figures.html

Your statistics are seriously flawed. For example, your math in point 2 assumes you will certainly find yourself in a life threatening situation while carrying the device. And your point 3 probably vastly overestimates the fraction of life-or-death calls.

Your statistics are seriously flawed.

Actually, I think you a) misunderstood the claim in point 2, and b) take issue with the assumptions - not the math/statistics - in point 3.

your math in point 2 assumes you will certainly find yourself in a life threatening situation while carrying the device.

In point 2 the likelihood of a life threatening situation was not assumed or calculated (that's point 3). The conclusion, restated: If there's a 1/3500 chance you'll be able to effectively use the device to save your life, you're breaking even while mitigating risk.

And your point 3 probably vastly overestimates the fraction of life-or-death calls.

You've stated that I've made assumptions and you're right - which is why they're labeled as such. Feel free to suggest yours.

I carry one of those when I go backpacking. The satellite transmission they send to summon rescue includes your GPS position, and they also serve as short-range beacons to help rescuers zero in on you when they get close. That can be crucial if the PLB can't get a GPS lock, because rescuers might only know that you're located somewhere along miles of road or trail. If you're unconscious and out of site a few yards from the trail, the beacon might be the only way for them to find you fast enough to help.

Found an update on the toddler who froze in 1994: http://www.cbc.ca/news/canada/saskatchewan/story/2009/02/20/...

I spent the whole article translating those temperatures into Centigrade. Kind of broke the flow.

Seriously, has anybody created a decent userscript or browser extension to fight this problem yet? I had no luck searching for one.

If you're quick at math here's a fairly accurate way:

F->C: Subtract 30, divide by 2.

C->F: Double it & Add 30.

Often known as the "Bob & Doug McKenzie method" from around here it makes for fast conversions since the actual conversion (°F - 32) * 5 / 9 = °C is close enough when dealing in the normal temperature range of weather.

That's really interesting and something I will have to remember. My friend is from the UK so when we talk about temps (they don't get the winter we get in my area of the US) I try to convert it.

I've been counting along increments of 1.5 in whichever direction from 0 C or 32 F.

I probably made it a .5 for mental calculating.

Just out of curiosity I tried yours and it even works with minus temperatures, although a bit confusing at first.

Yours are exactly the reason I read the comments on posts.

edit: to make it a bit clearer

Edit, ignore the following:

Worst was where they switched without even mentioning it. One paragraph they're still using F and said "The lowest recorded core temperature in a surviving adult is 60.8 degrees.", then the very next paragraph, with no talk of changing units, they talked about people dying "though temperatures never fell below freezing and ranged as high as 45". Just because the second story happened in England..?

That's still 45 degrees Fahrenheit. They were talking about outside temperature, not core temperature.

I'm also questioning if you have a sense of either temperature scale. It's quite funny to think that it could reach 45 C in England at all, much less that people would freeze to death in it.

My bad, of course you're right. And no, not a great sense of temperature scales - in the UK I pay attention when it's down around freezing (in Celsius) and in LA I pay attention when it's hot, 100+ in Fahrenheit. Other than those two occasions I guess I don't really notice or care.

Edit: funnily enough, 45C turns out to be the hottest temperature I've personally experienced, the day LA set it's record high in September 2010.

Easiest way to do off-the-cuff conversions:

- Celsius scale is based on water freezing at 0C and boiling at 100C. That's 32F and 212F, respectively.

- 45C is about halfway between 0C and 100C, so it's about halfway between 32F and 212F.

- Normal body temp 98.7F or 36C.

- Also -40C == -40F. I looked this up once because I was out on a day that where the wind chill was -40F. I thought that I did something wrong when the conversion came out exactly the same. ;-)

F = C * 2 + 30

Gets you to within a couple of degrees for commonly experienced temperatures, plenty close enough for most purposes. 45C ~= 120F. The true value is 113F.

They do use kilocalorie that is defined with degrees of celsius though. It isn't as bad here, but unit mixing is extremely annoying in aviation books in canada. In the same chapter of "From The Ground Up" you can see nautical miles, statutory miles, multiples of thousands of feet for height (took me a while to realize a mile is not a multiple of 1000 feet, wtf?), degrees of celsius, pounds, kilograms, kilopascals, millimeters of mercury and so on. At least I haven't seen degrees of fahrenheit anywhere...

I also find it completely strange that here in the US people tend to use feet as a sub-division of miles, but the mile/foot relation is not trivial: 1 mile == 5280 feet. And why would you need so many units for length? mile, yard, feet, inch... All (apparently) unrelated.

The metric system on the other hand, is so elegant and simple. Only one unit: meter.

Growing up in the US, we're exposed to these units our entire lives. End result? When my GPS tells me to turn right in a quarter mile, I can eyeball that distance. If it told me to turn in 400 meters, it'd make me pause a bit.

When I buy a gallon of gas, I know what I can expect to get from it. I know roughly how much a gallon is and how much a liter is, but I'd have to do math to tell you how far my car will go on a liter of gas. Don't even ask me me how many liters I need to travel 100 km…

It doesn't help that gasoline is sold only by the gallon, fuel efficiency is given in miles per gallon, speed limits are in miles per hour, and mile markers give our position on our highways and number our exits. Non-SI units are burned into our brains and our infrastructure all over the place. Grow up in that world, and the awkward math doesn't seem all that bad compared to having to get your bearings in a whole new system.

(That's not to say we shouldn't be switching to metric… but there are definite downsides for a population so used to our strange way of doing things.)

Besides, these length units do have integer relationships with each other: 12 inches to a foot, 3 feet to a yard, and 1760 yards to a mile. I find the first two easy to remember, and the third easy enough to calculate by remembering that one mile is 5280 feet.

But a yard is 0.9144 meters, making a foot 30.48 cm and a mile ~1609 m. Math within metric is easy. Math within our silly units is slightly more complicated, but we get used to it. Conversion between the systems is messy.

It's worth saying that lots and lots of countries have gone through this conversion process, sometimes multiple times -- think of all the countries colonized by the British (and thus converted from their existing systems to the British measures), who then sensibly converted to metric at some point after independence.

All of them were equally wedded to the pre-change system (fixed in mental habits, etc.), of course; there's nothing special about the American situation.

There's obviously a cost, but it's most severe for the older generation (whose mental habits are so ingrained they have real trouble adjusting) -- even for younger adults, your brain adapts to the new system after using it regularly for a while. AFAICT (I moved from the US to a metric-using country 7 years ago) it's never quite the same as the system you grew up with, but I'm pretty comfortable with it now.

It's something like learning bad words in another language -- they never gain the burned-in power of expletives in your native language, but your ears certainly learn to perk up when you hear them, and you can use them perfectly well.

Summing up -- quit whining, America, switch to better measurement systems, and the difficulties will smooth out more quickly than you think. :)

They are related, just in somewhat strange ways.

See: http://en.wikipedia.org/wiki/Mile#Roman_mile

No worst was mentioning absolute zero in Fahrenheit...

This was terrifying, I think because of its sheer realism. Nobody expects they're going to die when they decide to get out of their car and trek to the cabin in the dead of night. But it sneaks up on you through a series of small mis-steps and you could pay with your life for those little mistakes.

Should've stayed with the car. Should've called for help. Once he got out, he should've stayed on the road instead of cutting through the woods. Should've ditched the skis once they broke. Should've exerted himself less.

Lots of little should-haves like those are what can kill someone who's not prepared for and experienced with harsh conditions.

FYI this is from Jan. 1997. I remember reading it in one of those "Best Sports/Nature/Science Writing" anthologies back in school...a great piece, obviously if I still recall it 15 years later

Read this a while back but this passage:

"In 1980, 16 shipwrecked Danish fishermen were hauled to safety after an hour and a half in the frigid North Sea. They then walked across the deck of the rescue ship, stepped below for a hot drink, and dropped dead, all 16 of them."


As far as I can tell, this is an urban legend. That is, several people have looked for an account of this in the Danish papers, and found nothing. Here's one such person's report: http://www.reddit.com/r/todayilearned/comments/15jz7b/til_in...

The closest match was to "Other classic examples of post-immersion collapse include the survivors of the SS Empire Howard (Lee, 1971). The Captain of the ship, Capt Downey, reported: "everyone was conscious when taken out of the water but many lost consciousness when taken into the warmth of the trawler. Nine (out of 12) died shortly after being rescued", where "The SS Empire Howard was sunk by a U-boat on 16, April, 1942.

Great use of the first person - this made me physically uncomfortable. Much more so than third would have.

It's actually using the second person.

Haha doh. That would be what I meant.

No, that's what you meant.

I also found this to be one of the most intense things I've ever read.

Some time ago, during the winter we went to visit the Atacama Desert with my wife (she was born there). We rented a small car and my wife told me "are you sure this will work at 4,000 meters high? (13,100 feet)" - we were going to be travelling around some small towns and one of the roads reached that altitude. Stupidly enough, I replied to her "sure... these are modern cars, with fuel injection and smart oxygenation".

The roads were covered with snow, and suddenly we got stuck in a snow-covered road. Being a firefighter (trained in rescue) I had some idea of what I had to do... but of course, no shovel or any other tool to remove the snow. For 1 hour or so I tried to remove the snow with no luck. I got into the car, told my wife that the smartest thing would be to stay in the car. If necessary, the fuel in the car would keep us worm for days.

After some time, a car came down the road and helped us out... only to get stucked again, this time because the car actually got de-oxygenated at exactly 4,000 meters... Luckily this time the same car was behind us for a few minutes and we could push the car until the downhill.

Now we tell the story with friends and laugh about it. But if you ever go to some place that you have a slight chance of getting stuck in the snow: pack a shovel or at least make sure you have the fuel tank full. And never get out of the car wandering to find something.

A tip: http://lifehacker.com/5856986/use-your-floor-mats-for-tracti...

Always know your resources available!

Have somebody used it, ever? I did, once. Tyres just throws mats under the car, without much movement. If there's no friction between tyres and ice, there would be not friction between mats and ice, either. However, it could help on the snow or sand.

Although that is sound advice in the event you're caught in a small rift of snow, it will mean nothing when hitting a ditch that sinks your car to the frame in snow which is often the case in situations that the story illustrates.

I used to carry kitty litter in the trunk of my car when I lived in Vermont. Throwing a couple of handfuls under your tires would give enough traction to get going on ice.

That was a fantastic read. Incredible journey to hypothermia and back.

The description of the feeling of burning is unreal! What is even better is the incredible knowledge of how to revive a patient from this state.

I belief these techniques are used in heart bypass operations ?

Yes, they are indeed. As a medical student I had the privilege of seeing a heart valve being installed. They are a witness to how far medicine has progressed since the days of barber surgeons.

The blood is taken out of your body through the femoral vein (under the skin between your hip and your nether regions), taken through the perfusion machine and pumped back into the femoral artery. Because at this stage the heart will have been stopped, the high pressure in the femoral artery makes blood flow backwards up the aorta, where it supplies oxygenated blood from the machine to the whole body.

At one stage the flow has to be switched off in order to sew the metal valve onto the top of the aorta. In preparation for this, the blood leaving the perfusion machine is chilled (I'm not sure to what temperature). This slows the body's metabolism down and would cause hypothermic stupor if the patient had not already been under anaesthetic. I was told by the perfusionist that this gave the surgeons around an hour of extra operating time before the brain's oxygen content dropped to dangerous levels. All this is of course monitored by the anaesthetist and the perfusionist. The hypothermia will be reversed during the process of reviving the patient.

With the advent of endovascular procedures, this sort of surgery is becoming a rarity. It's much easier to pass a small tube up the aorta and inflate the narrowed artery from the inside than it is to open up the chest and sew a new blood vessel onto the heart. Of course, the medicine's more boring but it's all about getting a good outcome for the patient, isn't it?

As a medical student you'll appreciate that I have a 3-4" stint replacing a section of my aorta, starting about 1mm away from the aortic root.

This to repair an ascending aortic dissection that terminates in my left iliac.

I walked out of the hospital, but the recovery was a PITA.

My core temp got down to 18C (65-66F) for over an hour. (According to the surgical notes I was on the heart lung machine for over 4 hours, and without perfusion for 45 minutes.)

I think it's a testament to modern medicine that we can do these sorts of things. Glad to hear you got through the recovery alright. With the operation I saw, they packed the patient's head with ice bags as well as cooling the blood. I remember thinking to myself that I'd hate to be that guy waking up! Something like a large hangover ;)

Oh yeah, 20 years ago and I'd have never survived the night.

Whole thing is here, http://aorticdissection.com/2011/12/06/jim-thompson-47/ though I assumed that the termination was the right iliac until last Spring, when I had them run a CT on the lower extremities, and found that the termination was in my left leg (and that the false lumen had blocked the iliac in my right leg.)

Maybe when you're a doctor you'll remember, "When the symptoms don't make sense, think dissection" and save someone else.

Amazing, the knowledge acquired, distilled and shared to enable this is just wanted immense. My father had a major bypass op 6 years ago and I remember him saying how he felt when he first awoke after the surgery. He mentioned feeling cold!

I felt very cold waking up after surgery for lung collapse (as in, shivering uncontrollably, not really hypothermic I guess). I don't think they specifically lowered my temperature. Maybe that is a common effect of general anesthesia?

Those heated blankets they have in post-surgery rooms are very nice...

Shivering is a common side-effect of general anaesthetic. I've not seen enough post-op recovery to know exactly how common, but it's high on the list of side-effects we have to tell people.

WRT the hypothermia, you may have been slightly hypothermic as a result of having so much of your body surface exposed to the air. People don't realise that ambient temperature (18-22C) is actually quite cold in relation to body temperature (36.7C) - it's only the fact that we wear clothes that means we don't feel it.

Nowadays we have heated blankets in theatre too, to offset this heat loss.

Being cold and being deathly cold are two different things.

I've only gotten mild frostbite once, but I'd never want to have it again. The skin blackens and peels, and itches like nothing I've ever experienced before.

Frostbite and hypothermia are two different things and often happen under different conditions. As noted, you can get hypothermia in (relatively) mild temperatures if you're wet, tired, dehydrated, etc. Frostbite tends to be the result of colder temperatures often in conjunction with wind. But, yes, both are bad. I've also had fairly mild frostbite of the ear lobes (a pretty common place) and it's not fun. The thing to be aware of though is that it doesn't have to be especially cold to get hypothermic. In cold weather hiking, some of the conditions you need to be most careful in are 35 degree or so rain.

I've been lucky enough to never experience real hypothermia first hand.

Mild frostbite != blackened skin. I'm curious of what situation you got yourself into because that sounded fairly serious.

My pants got stolen while I was attending life guard classes. I had to walk home in ~30 degree weather in the snow in wet swim trunks.

I sometimes make bad decisions.

I read this years ago and it really stuck with me. Now when I venture out into inclement weather I always load up the car with blankets, water, food, ratchet straps, and other emergency supplies.

Somehow this reminded me of this excellent story: http://www.signandsight.com/features/852.html

I used to routinely go out in the bitter cold in Wyoming. Wearing lots of military-issue clothing. Dressed and behaving as the military recommended, I found -40 to be quite tolerable. Coming from Florida, without the military training, I'd have been dead.

What's amazing to me is Eskimos lived without fire.

Where did you get that information? The Inuit traditionally use a qulliq/kudlik (a lamp fueled by seal oil) for light, heat, etc. and everything I can find now says that it's not something introduced in the last couple of hundred years. For example,


says that Inuit were curious why people were hunting whales for oil for light, when they knew that seal oil was better for the qulliq.

Ahh, even better. The Dorset culture (http://en.wikipedia.org/wiki/Dorset_culture - 500 BCE–1500 CE) used soapstone lamps very much like the the qulliq for heat.

Can you find anything that says fire was a necessity for survival for paleo-eskimo cultures because I remember reading it wasn't, but I'm having trouble googling a source for or against it.

I don't know about "necessity". Only that it was part of the Dorset culture for 2,000 years, and used by even earlier Arctic cultures.

A search for "dorset soapstone lamps" finds plenty of examples that lamps were used, and even pictures of the archeological finds of such lamps.

http://books.google.se/books?id=kGWuMa6sRYsC&pg=PA372... says "Winter light and heat were supplied by soapstone lamps ... The previous Dorset inhabitants of Arctic Canada had used soapstone lamps for some 2,000 years. ... Soapstone cooking pots ... "

http://books.google.se/books?id=iBCc5bQlP1wC&pg=PA179... has "The most conspicuous difference between Saqqaq and Dorset sites lies in the occurrence of fire-cracked rocks. These are common in Saqqaq sites ... During the Dorset culture, the heating of winter dwellings relied on the use of soapstone lamps."

(Note that "Saqqaq culture existed from around 2500 BCE until about 800 BCE", so is before Dorset, pushing back the use of fire even further.)

Or for a regular HTML link, http://www.thecanadianencyclopedia.com/articles/dorset-cultu... says "Dorset culture, 500 BC-1500 AD, is known archaeologically from most coastal regions of arctic Canada. The Dorset people were descended from Palaeoeskimos of the PRE-DORSET CULTURE. Compared to their ancestors, the Dorset people had a more successful economy and lived in more permanent houses built of snow and turf and heated with soapstone oil lamps."

I don't know whether it's true (haven't googled it) but the natives of Tierra del Fuego were reported not to use fire much & to wander around nekkid. The natives didn't survive contact w/ Europeans very long, however.

They used fire to help keep warm, for light, and to cook. See, for example: http://www.britannica.com/EBchecked/topic/555978/South-Ameri... :

> Among the archipelagic tribes of southern Chile it was predominantly the women who gathered shellfish on the beaches at low tide and who, from bark canoes, dived with a shell blade and a basket held in their teeth. The shellfish gatherers were careful not to exhaust the supply in one area. These people also always carried a fire on a clay platform in their canoes, both for warmth and for roasting shellfish over the coals. The men hunted roosting cormorants, penguins, steamer ducks, petrels, and other marine birds at night with torches and killed them with clubs. Ducks and geese were lured by decoys, then captured with pole snares.

These people are really interesting. Going to read more about them, thanks!

It is actually quite amazing what it is possible to survive. The hypothermia "record", so to speak, was broken shortly after this article was written. See e.g. http://en.wikipedia.org/wiki/Anna_B%C3%A5genholm http://edition.cnn.com/2009/HEALTH/10/12/cheating.death.bage...

One thing I have started doing when I go on any outdoor treks, even just a day of snowboarding, is carrying a portable amateur radio. I program in the local repeaters if there are some (not always an option depending on area) which greatly extends range if necessary. Not as good as a PLB in some ways, but superior in others. For example, I can call for help without bringing in the whole cavalry.

I had a philosophy professor who taught Existentialism, and he told us the story of how he almost froze to death while hiking . How he started to hallucinate that death himself had come to take him away. Eventually, he said he became calm and accepted his fate, and that freezing to death wasn't a bad way to go. Too bad he retired that semester, what an interesting guy.

This older (not that the article we were reading wasn't from 2002) article is very similar: http://www.guardian.co.uk/lifeandstyle/2001/mar/01/healthand...

Just to tie this back to the tech industry and why relying on GPS only can be dangerous


Did you read what you linked?

"Because of Mr. Kim's background as a technology analyst, observers speculated that the family had used online mapping to find their route. However, Mrs. Kim told state police that they had used a paper road map, an account supported by the Oregon State Police, which reported that the Kims had used an official State of Oregon highway map."

It's still relevant to the posted article, though perhaps not exactly for the reasons stated.

No I didn't, I the original search for him and his family and the immediate aftermath that there was a great deal of discussion about them getting lost due to following a bad GPS route.

I don't think they used GPS though. But here is another story where the GPS was misleading (Disclaimer: It was pointed out to me by another hn reader, although I don't know exactly who): http://www.usaprepares.com/survival/husband-died-just-six-mi...

I might be mixed up on it. Gosh it's hard to imagine that was six years ago.

Handy tip, best "snow shovel" for digging yourself out is a grain shovel. Keep one in your car in winter.

"You sweat, you die". That's what I have learned watching those survival shows (Survivorman, etc)

This is an excellent read indeed.

Great writing, the story was somewhat interesting but the writing was great.

Anyone else find the second-person narrative distracting?

> by Peter Stark


I teach search and rescue people how to travel on skis or snowshoes and live in winter mountains. If you are prepared, you can stay out in sub-zero for days and days very comfortably.

A key skill is constant regulation of your body temperature. You never want to become too hot/sweaty or too cold. If too cold - get into shelter, drink something hot, eat carbs, add clothes, move faster. If too hot - remove clothes, or move slower. Fix temperature problems immediately - never tough it out.

Common mistakes: people get distracted by gadgets, or they get impatient and start to wander. Then they lose awareness of their body temperature, and become hypothermic. Once you get hypothermic, things fall apart fast.

If you do winter travel in remote areas, carry warm clothes, water and food. Then if you get stuck, be patient and steady. Follow this advice, and the odds of freezing to death go way down! :-)

I agree with all of this advice.

The article describes one type of winter danger (extreme cold), but there's another equally dangerous condition it doesn't deal with — temperatures right around freezing.

A friend and I ended a snowcamping trip a day early yesterday because temperatures were ±32º morning and night. The result of the temperature staying just below or at freezing is that you get very wet. You get very wet just doing mundane tasks like shoveling snow because your body heat needs to shift the temperature of snow on your clothing by just a few degrees to melt. Being slightly unprepared for a night in these conditions is just as dangerous as being in the arctic (where you may be cold, but you'll definitely be dry).

If you're out with others when it's cold, be aware of the "umbles":

Stumbles, fumbles, mumbles and grumbles.

These can be relatively early external signs of altered mentation and potentially of the on-set of hypothermia.

Hypothermia can occur even in fairly warm temperatures, too; you don't need freezing temperatures.

When carrying food, remember you're going to be eating a whole lot more when it's cold and you're exercising.

Avoid cotton clothing, as that gets and stays brutally cold when it gets wet. Wool or synthetics work much better.

Never go out with Flint Fireforge. Got it.


In general, if you're driving somewhere remote and something goes wrong, you're almost always better off staying with your vehicle vs. setting out on foot for help. There are obviously exceptions, but as a general thing, it's true.

That reminds me of the sad story of CNet editor James Kim. He got caught in a snow storm with his family. He left the car and died trying to get help. His family was rescued in good condition. Had he stayed with them, they all would have survived.


The "family gets lost, guy goes off to find help, gets even more lost and dies, and then the rest of the family is rescued" is a pretty standard story.

Today, in the age of gps enabled cell phones there is no reason to leave the car (unless there's a risk of explosion, car sliding off a cliff, etc, etc)

Get your position, call 911, wait.

If the signal is not good enough to make a call, send an SMS

What if the signal isn't good enough to send an SMS?

I'd tend to agree that staying with the car is sensible. Maybe with some bright orange tarpaulin / flag thing over the car (although that'd probably get buried in snow.)

At least if you're travelling in really bad weather you know you might get stuck and so you should prepare.

People in England were caught out when light snow was forecast; they left work early and joined the M25 at the same time as the road gritters, which caused a weird cascade effect and blocked a major motorway in the UK for 24 hours when there was only 1 or 2 cm of snow.

Then write your SMS, try sending it and try exploring different positions (maybe try exiting the car, or even climb it). Just don't wander away from it.

In my experience, the phone will retry sending the SMS a couple of times if the signal is low.

When I go riding around central Utah on my motorcycle (note: these are paved roads with a street motorcycle), I'm often out of cell coverage for hours at a time. The reality is that the high mountains and deep valleys for "real" mountains, combined with the lack of towns, provide for no coverage, either SMS or cell. If I got caught in those places in snow that is feet-deep, I wouldn't expect my electronics to free me.

Yes, there are huge areas without cell coverage

Still, having a gps is helpful (at least you know where you are and can wander but knows how to get back)

Having an automotive gps with maps is even more helpful

But yeah, it is a very bad situation nonetheless

If you have any cellular reception at all, you're generally not lost or stuck in the wilderness and at risk of freezing to death.

I don't think that's right. I've been places in Colorado miles from "help" and still had cell reception.

The metric "miles" isn't as useful as the time it takes for that help to actually arrive.

I would probably be more likely than most to leave my vehicle but I have training in mountaineering and I wouldn't do so without a good plan and sufficient equipment. My car always holds a basic level of backup supplies including: a first aid kit, a bottle of water (which can also serve as a water container), a head-lamp with extra batteries, a multi-tool, matches, a fleece blanket, rain gear (including rain pants), mylar thermal blankets, and a simple drawstring backpack (which holds the blanket and rain gear) in blaze orange.

Even in a worst case scenario where I happened to drive up into the mountains in just jeans and a t-shirt and get caught in a snow storm and nobody knew where I had gone I could easily travel for several days through the back country (let alone alone the roads) with just that equipment. And if I stayed with my car it would definitely extend the amount of time I could survive until rescue arrived. The total cost of all of this stuff is almost nothing, it's worth it to be prepared.

I don't really leave a 2hr radius of SF now (although I guess I drive to Front Sight and Vegas sometimes, but prepare separately for that), and have all that stuff and more. Case or two of water, some tools, often a range bag with items, etc. Mostly worried about responding to someone else's accident, but there's the lingering fear of an earthquake, big fire, or other event like that. This is one of many reasons I like having my own car vs. zipcar or public transit -- it's 100 pounds of things to deal with emergencies (including "server broke, need tools and some network cabling", which is a much more common emergency for me than gunshot wounds...)

I really want to get into bay area amateur radio and get on some repeaters and stuff. An HT in the car seems like it would be a good addition. Maybe 2013.

If you read the annual compilations of mountaineering accidents in North America you'll notice a few trends, generally people being under prepared and having insufficient basic equipment like lights, warm clothing, or rain gear. A common theme is people getting lost or poorly estimating time or getting caught by weather and then being forced to spend a night out on a mountain when they hadn't planned to. Generally, just being more knowledgeable and trained can help though also making sure you always bring those "ten essentials" also helps a great deal and they don't add much weight or hassle if you do it right.


I just saw a list of the "ten essentials" posted at the entrance to a wilderness area in New Hampshire's White Mountains. I'm somewhat embarrassed to admit that I was without many of them, though it was on a day hike with a partner on a very wide, flat, heavily-traveled trail. I remember a spring backpacking trip in the Smoky Mountains where one person in my group fell into a creek we were crossing near nightfall as it was beginning to snow. Fortunately we had extra dry clothes ready at hand to give that person to change into.

Lots of good points. Its also, perhaps counterintuitively, the case that wet and above freezing is almost more dangerous for hypothermia many times. Snow is a source of potential shelter and insulation, provided a minimum level of preparation. But, being un-prepared ans without shelter in cold rain is a very dangerous place to be. Your core only needs to get to 70 degrees to kill you, etc. So its all about the differential and exposure.

An emergency blanket or bivy is extremely useful too and weighs very little. I just came back from spending a night in the snow (http://i.imgur.com/yc0cc.jpg sunset, Sequoia National Park, ~8,000 feet). At night, temps went down to the 20s (fahrenheit) I believe and I was shivering pretty bad in my sleeping bag until I took out my emergency blanket. In the morning, I cut it up and wrapped the pieces around my feet before putting on my boots, since I was still using soaking wet socks from the previous day (lost my extra pair somewhere on the trail). The mylar isn't breathable though so one has to watch out for perspiration.

Thank you for specifying Fahrenheit. Given there are different temperature scales used throughout the world, I always appreciate people who take the effort to clarify. Thanks ... Oh, awesome pic!!

The one time I fount myself at risk of hypothermia was because I had overestimated the cold. I put on too many layers which kept me nice and warm. But exertion in that warmth caused me to break a sweat. By the time I got where I was going things were just bad enough to make me feel like I had learned a lesson.

I can't say that I've been in extreme cold or dressed with lots of clothes, but I always undress in order to prevent (too much) sweat. Then I dress back as soon as I'm getting cold.

The best defense against the cold I find, up until about 10F or lower, is several layers of long sleeve tshirts. You can add or remove layers rapidly with a rather good resolution (You can easily have 5 "settings") and if you get wet they are very quick to dry (separate them to dry them fast.) If you are out for several days, you can start to cycle which shirt is closest to your body, to delay discomfort caused by dirty clothing.

Canadian here, a lot of people don't realize how dry winter is the humidity can be very low on a cold day probably comparable to a desert environment.

I stopped reading once I saw "Fahrenheits". Fahrenheit and imperial system is what Microsoft is to software: non-compliance with internationally agreed standards.

Your loss.

good read, but more of a reddit material than a HN

How old is this article? It seems to use the old Fahrenheit temperature scale. I'm sure my grandfather would understand those temperatures but for myself I had to convert each one into modern units. Eventually I couldn't be bothered and stopped reading.

Frankly I'd rather use a system where 0 degrees is "fucking cold" and 100 degrees is "fucking hot", but neither fatally so, with 100 different steps in between.

Meh, I've stopped trying to ever argue stuff like this. There is simply a large class of people who will never believe in l10n if it involves en_US, only if it's any other country or region in the world.

You know Fahrenheit is used by the entire United States, right?

Switch to metric system USA!

tl;dr: the US has a long and tragic history of half-hearted attempts to switch to metric, beginning in the mid-1800s (when metric was made an international standard, with the active participation of the US... one of the original seventeen signatory nations to the Metre Convention), and continuing on through today, where the US is one of three remaining countries (with Myanmar and Liberia) that has not adopted the International System of Units (SI) metric system as their official system of weights and measures.

Along the way we get sad stories like the loss of the Mars Climate Orbiter in 1998, where everyone except Lockheed Martin was using metric units in the parts and software written for the orbiter.

So come on, USA! Keep trying!

New Fahrenheit is the same as old Fahrenheit. In other words, it never changed.

Unless you are joking, I think he was characterizing Fahrenheit itself as old, not saying there was a separate, "old Fahrenheit" scale.

Fahrenheit is old. Celsius is modern. The real avant-garde give all temperatures in kelvins...

Quit living in the past. We use Planck temperature now.

I didn't understand the temperatures either, and didn't even try to convert any.

The article is really well written and you'd be well-advised to read it despite your grievances with the units.

You could also mentally convert the temperatures, I can do it easily despite never having lived in a country where Fahrenheit is used.

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