[OT]:: Snow Avalanche - NZ style

[RussellMc]

Even bigger than the ones in Texas :-)

_____________________________________

Awesome. Worth watching. BIG avalanche on Mt Ruapehu (2007). A bit tame to
start but from about 50 s on "you'll get the idea". Then it just goes and
goes. And goes. And goes & ...
This is a purposefully triggered "slab avalanche" similar to the type that
recently killed two very experienced climbers (& failed to kill their
climbing companion Mrs Jo Morgan), in Southland - but probably MUCH larger.

I've walked up there! (lonnnng ago)(although exactly where relative to that
avalanche I don't know).

[David Van Horn]

DHMO can be really beautiful when it's not trying to kill you.


-----Original Message-----
From: piclist-***@mit.edu <piclist-***@mit.edu> On Behalf Of RussellMc
Sent: Wednesday, November 7, 2018 5:29 AM
To: Microcontroller discussion list - Public. <***@mit.edu>
Subject: [OT]:: Snow Avalanche - NZ style

Even bigger than the ones in Texas :-)

http://youtu.be/JwtxNYt6r5U

_____________________________________

Awesome. Worth watching. BIG avalanche on Mt Ruapehu (2007). A bit tame to start but from about 50 s on "you'll get the idea". Then it just goes and goes. And goes. And goes & ...
This is a purposefully triggered "slab avalanche" similar to the type that recently killed two very experienced climbers (& failed to kill their climbing companion Mrs Jo Morgan), in Southland - but probably MUCH larger.

I've walked up there! (lonnnng ago)(although exactly where relative to that avalanche I don't know).
--
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[RussellMc]

On Thu, 8 Nov 2018 at 02:08, David Van Horn <

Post by David Van Horn
DHMO can be really beautiful when it's not trying to kill you.
It can. And even when it is lurking waiting to kill you if you put a

(almost literally) foot wrong.

As I noted, I walked up that mountain (Ruapehu) long ago and have skied
(for some values of ski) on the middle and upper slopes on a number of
occasions.
We were not unaware of avalanche risk, but it was never made clear that a
very significant part of one face of the mountain might ever decamp
spontaneously.
I've seen TV footage of events where tearooms and some chalets and lodges
have been demolished by combinations of avalanche and lahar from the
usually-stays-in-the-lake crater lake*.

But, again, the idea of an avalanche so vast that it was inescapable at
hundreds and hundreds and .... of metres away never really entered my
awareness.


Russell

________________________________________________________________

DHMO - same source - different state. Tragic outcome.

* In 1953 the then "almost new" Queen Elizabeth and her husband arrived in
NZ on December 23rd.
The next day on Christmas eve Mt Ruapehu was volcanically and seismically
active enough to dislodge the barrier which retained 2 million cubic
metres** of water in its crater lake.
At about 10 pm a 6 metre lahar swept down the Whangaehu river and at about
10:15pm it struck the Tangiwai rail bridge - weakening it but not fully
destroying it.
At 10:21pm a train with 9 carriages and 2 'vans' commenced to cross the
bridge. The bridge collapsed and the engine and 6 of the carriages
initially fell into the torrent - with 151 people ultimately dying.
The train driver, who died, had applied the brakes about 200 metres before
the bridge

** 0.002 cubic kilometres of water !

30+ years later I found that a friend of a year or so had been a trainee
guard in the van at the rear of the train!

https://www.sooty.nz/tangiwai.html
RANSFIELD Hemi Matiaha - Assistant Guard
He almost missed the train !!!:
https://www.facebook.com/214182435266363/posts/some-memories-of-the-tangiwai/713565045328097/


1 https://nzhistory.govt.nz/culture/the-tangiwai-railway-disaster
2 https://nzhistory.govt.nz/culture/tangiwai-railway-disaster/wrong-place
3
4
5
6 https://nzhistory.govt.nz/culture/tangiwai-disaster/further-information

Legion:
https://www.google.co.nz/search?q=tangiwai+disaster&oq=tangiwai+disaster&aqs=chrome..69i57j0l5.6174j0j7&sourceid=chrome&ie=UTF-8


Even bigger than the ones in Texas :-)

Post by David Van Horn
http://youtu.be/JwtxNYt6r5U

[David Van Horn]

30+ years later I found that a friend of a year or so had been a trainee
guard in the van at the rear of the train!


"So I hear your first day was a little rough..."

[RussellMc]

On Fri, 9 Nov 2018 at 02:47, David Van Horn <

Post by RussellMc
30+ years later I found that a friend of a year or so had been a trainee
guard in the van at the rear of the train!
"So I hear your first day was a little rough..."

Probably not his first, but could well have been his last had not both the
engine driver and engineer reacted as well as they did.
It sounds like the train commenced braking about 6 seconds before it
entered the bridge. Add a second or so of reaction time and another (at
least) to get it braking* and the sand release going.


Russell

* I don't know what the propagation time is of a vacuum braking event along
a train once activated. Not long, you'd hope.

[Martin McCormick]

Post by RussellMc
Probably not his first, but could well have been his last had not both the
engine driver and engineer reacted as well as they did.
It sounds like the train commenced braking about 6 seconds before it
entered the bridge. Add a second or so of reaction time and another (at
least) to get it braking* and the sand release going.
Russell
* I don't know what the propagation time is of a vacuum braking event
along
a train once activated. Not long, you'd hope.
--

I have been told that it is the speed of sound. That
makes sense since we're talking about air but I also read
somewhere that there is a solenoid-based breaking system being
developed which probably releases all the air breaks
simultaneously which would help stop a very long train.

Martin McCormick WB5AGZ