Naked Science Forum
Non Life Sciences => Geology, Palaeontology & Archaeology => Topic started by: thedoc on 07/06/2012 15:43:36
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We explore how sand can be used to predict the outcome of an avalanche...
Read a transcript of the interview by clicking here (http://www.thenakedscientists.com/HTML/content/interviews/interview/2106/)
or [chapter podcast=3995 track=12.05.20/Naked_Scientists_Show_12.05.20_10186.mp3](https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Fwww.thenakedscientists.com%2FHTML%2Ftypo3conf%2Fext%2Fnaksci_podcast%2Fgnome-settings-sound.gif&hash=f2b0d108dc173aeaa367f8db2e2171bd) Listen to it now[/chapter] or [download as MP3] (http://nakeddiscovery.com/downloads/split_individual/12.05.20/Naked_Scientists_Show_12.05.20_10186.mp3)
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Interesting.
But, I wonder if the characteristics of sand (wet or dry?) is the same as snow which can also be rather icy, or not. However, it is interesting that the rate of accumulation affects the scale of the avalanche. I would think one would also gain information by looking in the natural environment, such as the Alps where the avalanches must be common.
As far as new avalanche technology, one of the newest things on the market is the Avalanche Airbag (http://www.wildsnow.com/3736/airbag-overview/), which is supposed to significantly increase a person's chance of survival. With some skiers already surfing an avalanche down the mountain. Video in Action (http://www.youtube.com/watch?v=h7QFRXc0R8M)
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Being a backcountry skier, I listened to the avalanche story with interest. Though I only listened to the podcasted portion, I found it curious that the focus only seemed to be on the flow dynamics.
There is a whole lot more to snow avalanches than what I expect can be modeled with sand. There is the stratigraphy of the deposited layers, buried hoar, depth hoar, temperature faceting, windloading, slab formation, and weather (temperature/wind) changes. All these play a factor on whether an avalanche will initiate spontaneously, or with an external (human) trigger, or whether the slope will be inherently stable.
The type of avalanche, dependent on the above conditions, is also important to the flow characteristics. A slab avalanche, where a large mass of snow begins to move at once is much more inherently dangerous to a skier / climber / structures as it can entrain a massive amount of snow in an instant. Loose snow slides can be relatively benign, as the snow may never build up sufficient mass to propagate (though a skier could potentially still be buried in a terrain trap). A wet slide can be so slow as to allow people to clear out of the way, but the weight can be destructive, and can also carry unwary people over terrain hazards.
Obviously, sand as a model can only cover certain aspects of avalanche physics. It would be great to hear a more in-depth (no pun intended) discussion of avalanches, it is a fascinating subject.
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interesting indeed,
My initial reaction was similar to Jschuh - there are many factors in an avalanche that cannot be easily modeled with sand. Most of these have been studied (at least emprirically) in the field. However, as the purpose of the reserach appears to relate to macroscale hazards to infrastucture (rather than small scale hazards to individual skiers/ mountaineers) it clearly has a point.
That said, the aspiration to "...be able to model snow avalanches from a physical point of view to actually be able to apply it to every valley and every mountainside in the world." whilst noble would have to consider all of the other factors that sand cannot model - such as stratigraphy, initiation & substrate.
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I only see that the same way computer software for making models of crowd control in built up areas and results prediction of stampedes operates. With water or sand you could create some type of viscosity and stickiness model from the polar covalent attractions result but i don't think either will be truly successful at predicting the final result.