
Bombing forest fires sounds ridiculous, but is grounded in physics - raleighm
https://www.popularmechanics.com/military/weapons/a22674251/air-force-bomb-forest-fires/
======
mindcrime
Using explosions to put out fires isn't an entirely novel idea: it's actually
used in oil-well firefighting[1]. That said, I have some serious concerns
about the applicability of this technique to wildland firefighting.

In the interest of full-disclosure, I am a former firefighter, but I was
mainly focused on structural firefighting. We did respond to wildland / brush
fires, but only got involved in direct suppression activities on the smaller
fires. Larger wildfires we just provided protection for exposed structures and
let the Forestry Service handle the primary suppression efforts. Anyway...

One of the main dangers of wildland fires involves something called the
"wildland / urban interface"[2]. This is where homes and urban construction
border on and/or intermingle with wildland areas. When you hear about
"Wildfire X destroyed N homes" this is usually referring to events that happen
in the WUI. I don't think it's hard to see how dropping bombs in this area
could be problematic - even using the specially tuned bombs referred to in the
article.

Also, a wildland fire isn't like an oil-well fire in that you don't have all
the fire concentrated in one small, well-defined area, where you can quickly
"snuff" it out. In a wildland fire - especially in the driest, most dangerous
conditions - it seems likely to me that the same shockwave that snuffs out
flames in a certain area, might well spread embers that actually spread the
fire to an even larger area.

Maybe there's something to this, but overall I'm somewhat skeptical.

[1]:
[https://en.wikipedia.org/wiki/Oil_well_fire](https://en.wikipedia.org/wiki/Oil_well_fire)

[2]:
[https://en.wikipedia.org/wiki/Wildland%E2%80%93urban_interfa...](https://en.wikipedia.org/wiki/Wildland%E2%80%93urban_interface)

~~~
bcaa7f3a8bbc
_> Using explosions to put out fires isn't an entirely novel idea: it's
actually used in oil-well firefighting_

Probably the most powerful explosive used in such firefighting was an atomic
bomb, which was used by the Soviet Union in 1966 to put out a large oilwell
fire in Uzbekistan.

photos and the video...

[https://www.mirror.co.uk/news/world-news/soviet-union-
detona...](https://www.mirror.co.uk/news/world-news/soviet-union-detonates-
nuke-underground-11169169)

~~~
mikeash
The word “probably” seems highly unnecessary.

------
dev_dull
> _severe droughts, meaning more dry fuel, as well as more intense heat
> waves”. The conditions set the stage for more, larger fires throughout the
> year. The trend will threaten people, property, and natural spaces_

It’s funny that we often phrase forest fires as some ecological disaster, when
in reality they are a normal and healthy part of a forest. I fact, some seeds
won’t even germinate until they’ve been roasted by a forest fire [1].

It’s only now that we live all around and inside them that it’s become _our_
problem.

1\. [https://www.britannica.com/list/5-amazing-adaptations-of-
pyr...](https://www.britannica.com/list/5-amazing-adaptations-of-pyrophytic-
plants)

~~~
Tempest1981
But are the severe droughts "normal and healthy"? California has over 100
million newly-dead trees in the last few years, which is unprecedented.

[https://www.livescience.com/57124-california-drought-
killed-...](https://www.livescience.com/57124-california-drought-
killed-100-million-trees.html)

~~~
ummonk
Severe droughts are historic to California (and therefore "normal", though
perhaps not "healthy").
[https://www.nytimes.com/2015/04/14/science/californias-
histo...](https://www.nytimes.com/2015/04/14/science/californias-history-of-
drought-repeats.html)

------
anonymous5133
I think it is a realistic firefighting tool but overall I think we just need
to get more realistic about how we live with wildfires, especially in
ecosystems that are specifically adapted to have wildfires. For all homes
built next to a fire line/brush area make sure they have systems implemented
to prevent them from burning. For urban areas you can just have exterior
sprinklers. If the area is a subdivision then have a good margin of brush-free
clearing. Have a water suppression system built in place to pump water
directly on the burning zones. Then you simply let the fire burn itself out
until it reaches the fire suppression system knowing that system will stop the
fire from destroying homes.

For homes that are directly in the forest areas (rural) then we just need to
build those homes with fireproof materials and have some sort of basic fire
suppression system. Maybe a fire-proof/heat resistant tarp over the structure?
Perhaps a novel solution would be to simply build UNDERGROUND homes in these
areas instead. No need to worry about fire at that point. I am watching the
news and see a lot of these structures and just wonder what the people were
thinking when they built it. Really...a log cabin in a forest that is known to
have forest fires somewhat regularly?

~~~
vinceguidry
Building homes underground is an order of magnitude more costly. And people
like windows. And you'd have to build them pretty deep and have some really
good entryway insulation before you can stop caring about a wildfire raging
overhead. Those things get _hot_.

------
jpollock
The problem with bombing a forest fire is that not all bombs that are dropped
explode. So, instead of a fire that will eventually stop being a fire, you've
got a fire and an unexploded bomb.

~~~
jessriedel
What is the failure rate of modern ordinance?

~~~
ethbro
_" The quality required of fuze designs is usually specified by two values:
functional re-liability, which ranges typically from 0.95 to 0.99 for complex
missile fuzes, and to 0.999 for projectile and bomb contact fuzes; and safety
reliability, for which a failure rate not greater than 1 in 106 must be proved
prior to release of items for service usage."_

[https://fas.org/man/dod-101/navy/docs/fun/part14.htm](https://fas.org/man/dod-101/navy/docs/fun/part14.htm)

The reason cluster munitions were banned is that the form factor and econonics
lead to less reliable detonation, not because we can't build a reliable fuze,
given a larger space and weight budget.

~~~
perl4ever
1 in 106 is a strange ratio. It seems that this article was reformatted,
particularly because of all the random hyphens. Is it possible that the
original said "1 in 10⁶"? I would be a little concerned if I was in the
military dealing with bombs that had around a 1 in 100 chance of exploding (or
even arming) unexpectedly.

~~~
maym86
Yeah 1 in 106 seems like an unbelievably high allowable failure rate.

~~~
perl4ever
I think " _functional_ reliability" of > 0.95 means that a failure of 1 in 20
to detonate could be acceptable, whereas " _safety_ reliability" of > whatever
refers to the chance of improper arming of a weapon. False negative vs. false
positive, if you will.

While both could be catastrophic under some circumstances, it seems reasonable
that you would expect "safety reliability" to be much higher because it's
tested more often. Near the end of the document it talks about how safety
reliability should be very high.

~~~
ethbro
I'd strongly suspect it was OCR'd 10^6 into 106.

Specifically as they talk about using multiple systems _in series_ to increase
safety reliability, where every system must function correctly in order for
the weapon to be armed.

------
wck0
"...an aircraft will generate a sonic boom along the length of its flight path
at a rate of one mile per thousand feet."

Can someone explain what is being measured as one mile per thousand feet?

~~~
sandworm101
Doesnt matter. Sonic booms have virtually no real power. All the tales of them
breaking windows and starting avalanches are pure myth. (See the anti-concorde
media campaign.) Forest fires release atomic bomb-levers of energy. A slight
puff from a tiny f-15 is a butterfly compared to the winds generated by the
fire itself.

~~~
danielvf
Here’s the Brazilian Supreme Court windows breaking from a sonic boom.

[https://youtu.be/43Kl7c2yU3g](https://youtu.be/43Kl7c2yU3g)

~~~
sandworm101
Yes. One or two breakings here and there when all the conditions are perfect.
Look at the mythbusters tests with the usaf. They came to nothing. Ive sat
under many an f18 doing a mach1+ flyby (rcaf). Car stereos create more power,
and worldwide probably break more glass.

------
AndrewKemendo
This is what Boots and Coots did so well during the Kuwaiti Fires that were
started during Desert Storm.

A great documentary on the Kuwaiti fires shows this technique, along with
others, being used. [1]

[1]
[https://www.youtube.com/watch?v=L77BSBKvMJk](https://www.youtube.com/watch?v=L77BSBKvMJk)

------
zavi
We should at least try this while the fires are going even though it's
expensive. There's no wildlife in the middle of a fire other than rodents
under ground. Just bomb the area that's burning wider than the blast radius.

~~~
waterphone
As I replied to another comment, there's a lot more to object to than just
wildlife. Natural and cultural/archaeological resources can be destroyed by
explosions while fire may not destroy or damage them. (Think rock formations,
rock shelters/caves, rock art sites, and the like.)

~~~
zavi
How did they justify it in Sweden then?

~~~
waterphone
Just because another country does something stupid doesn't make it a good
idea. Also, as noted in another comment, the one time this was done in Sweden,
it was a fire _on a military base_.

In the U.S., cultural resource protection is one of the considerations in
wildlands firefighting, and a significant number of wildfires in the U.S. west
occur within designated Wilderness areas where minimum impact suppression
efforts are required by law. This means, e.g., you can't run a bulldozer
through to cut a fireline in Wilderness, and in some cases can't even drop
slurry because it might cause permanent staining on rock outcrops, damaging a
natural resource. Dropping weapons-grade bombs is going to be a non-starter,
as it should be.

~~~
briandear
Weird. Because there are all sorts of bulldozing at work right now in the
California wildfires: [https://www.ocregister.com/2016/07/13/these-bulldozers-
are-f...](https://www.ocregister.com/2016/07/13/these-bulldozers-are-
firefighters-too-plowing-through-dirt-and-danger/)

~~~
waterphone
Bulldozers are used in fireline construction, but not in designated Wilderness
areas. Wilderness restrictions were one example of why this is a bad idea, but
they are not the only reason.

------
yantrams
This reminded me of the technique of combating a forest fire with another from
the opposite direction. Read about it as a kid in Physics for Entertainment by
Yakov Perlelman.

~~~
robinwassen
We did it a few weeks ago in Sweden, burned 800 hectare (2000 acres) to slow
down the progress of the largest wildfire this year.

Source in Swedish: [https://www.svt.se/nyheter/lokalt/dalarna/800-hektar-skog-
sk...](https://www.svt.se/nyheter/lokalt/dalarna/800-hektar-skog-ska-brannas-
for-att-stoppa-skogsbranden-i-trangslet)

------
hotcrossbunny
To add unbounded credence to this idea, it's basically what Macgyver did using
nitroglycerin to put out a wellhead fire in the 1985 episode "Hellfire"

------
21
I feel a lot of people will object this because of wildlife. But even
excluding that, how can you be sure there are no persons there?

~~~
waterphone
There's a lot more to object to than just wildlife. Natural and
cultural/archaeological resources can be destroyed by explosions while fire
may not destroy or damage them. (Think rock formations, rock shelters/caves,
rock art sites, and the like.)

------
girzel
It's grounded in MacGyver!

------
big_paps
its seems totaly legit to use hydrogen bombs for fighting against wildfires.

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mindcrime
This came up a couple of days ago. I'll just leave this link to what I had to
say then.

[https://news.ycombinator.com/item?id=17726721](https://news.ycombinator.com/item?id=17726721)

~~~
dang
We've merged that thread into this one and rolled back the clock on your
comment. Thanks for pointing it out.

------
mistrial9
.. except that "fire-dependent forests" are undergrad level knowledge in
Forestry Science.. e.g.

United States Department of Agriculture Forest Service Pacific Northwest
Research Station General Technical Report PNW-GTR-727 July 2007

~~~
fladrif
So are there plans in place to use fire proactively to do controlled burns on
overgrown / older forests?

~~~
alkonaut
Planned forest fires are pretty common

