
In 1674, a mysterious storm damaged Utrecht - DarkContinent
http://www.bbc.com/earth/story/20170407-in-1674-a-mysterious-storm-devastated-a-dutch-city?ocid=fbatl
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Maultasche
I was in Utrecht last October when I was visiting the Netherlands. The
cathedral that was ruined by that storm had a tower separated by a square
separated by what I call a "rump church". It was like a cathedral that had
chopped in half and was walled off in middle. It looked pretty weird. I'm
curious why it was never rebuilt.

The garden in the monastery next door was pretty nice. I enjoyed my visit to
Utrecht. My kids absolutely loved the railroad museum there.

I recommend going to the Netherlands. The people were friendly and I got a
chance to practice my limited Dutch that I had been learning. It's pretty
densely-populated, but it's a place a I wouldn't mind living.

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Grangar
Hey, my city on HN!

To clarify, 'Utrechter' is not the slur for 'homosexual'. It's 'Utrechtenaar'.
When the word became commonplace Utrechters switched to another word.

If you're ever in Utrecht I can also recommend visiting 'Onder de Dom' (Under
the Dom). It's an archaeological site where you can see the remains of the
middle part of the church, and also the foundation of the Roman fort it was
built on.

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pasbesoin
Sigh. Interesting -- but they take until the middle of TFA to actually say
what it was:

 _The problem is that a tornado is too localised and too confined to account
for all of the damage seen in Utrecht. It might account for destruction in one
particular district of the city, but it cannot explain why there were several
hotspots of strong activity across a wide region of northwest Europe.

But a particular form of storm system called a "bow echo" can.

Bow echoes are relatively new to meteorologists. The term was first used about
40 years ago, and as weather radar has become more widely used, bow echoes
have become easier to identify and study.

    
    
        Small differences in wind strength can generate small whirlwinds 
    

Bow echoes are broad, arc-shaped weather fronts – bow-shaped, in fact – which
can be tens to hundreds of kilometres long.

They pass over an area in a matter of a few hours at most, and they are
associated with strong and localised gusts of wind, called straight-line
winds.

These winds are related to downdrafts – winds that move vertically towards
Earth's surface at great speed. In the context of a bow echo, the winds flow
parallel to Earth's surface in the direction of the frontal system once they
reach the ground.

"We have been able to reconstruct the shape of the front by using historical
observations," says van der Schrier._

\----

P.S. If you live in the U.S. Mid-West, you are all-too-familiar with what a
bow echo is. Descriptions of them as such started making the weather news a
couple of decades ago. And the "echo" part refers to the radar return: The
radar "echo" shows the bow formation.

Here's the deal: You might have a storm front traveling at circa 60 miles per
hour. The strong cells within it produce downdrafts that deflect and run
parallel to the ground, maybe at 30 mph with respect to the cell. 60 mph + 30
mph gives a combined 90 mph wind relative to the stationary ground.

The heart of the onrushing front "speeds ahead" on this momentum and bows
forward, producing the bow shape in that part of the front.

I've been through very significant instances of this, with damage of varying
intensity across multiple communities with stronger spots here and there --
probably where local downdraft instances were particularly strong.

My parents were out of power for the better part of 5 days. That's how much
damage was done to their community.

Another aspect of these events: The considerable momentum can keep them going
for hundreds of miles. Storms that rip through the Chicagoland area can still
be manifesting this bow shape and creating damage when they get to e.g.
Virginia.

