Wikipedia:Reference desk/Archives/Science/2020 August 10

= August 10 =

Avalanche
I have seen multiple “near death captured on Go-pro” videos where a person is skiing and starts an avalanche. They then either try to outrun the avalanche or go with it but stay on top. My question is why don’t they just stop at the top of the avalanche and let the snow fall further down the mountain and then ski after the snow has settled? I have never skied and so have no concept of this and may be asking a stupid question but as Mark Twin said: “He who asks a question is a fool for a moment, he who does not ask is a fool for a lifetime.” Thanks — Preceding unsigned comment added by 31.53.187.190 (talk) 11:36, 10 August 2020 (UTC)
 * Actually it is not so easy to stop when skiing. Secondly if the snow is moving under your feet, it will not be possible to stop, and thirdly at the very start of the snow slide, it won't look like much and the skiier may keep on going, not knowing something big is about to go down, or hoping that it will settle down. Graeme Bartlett (talk) 12:36, 10 August 2020 (UTC)
 * Avalanches are often precipitated by the skis breaking the surface of the snow - described to me on a mountaineering course years ago as "a tear-here line". So as you go along across the slope, the snow falls away from under your skis. This article recommends that you find out whether the slope is avalanche-prone by making some trial ski cuts in a safe area before starting across. This article from the same site describes the more thorough process of digging a test pit to discover the adhesion (or otherwise) of the various snow layers; a thick layer of soft powder snow settling on a hard frozen crust is a recipe for an avalanche. Even worse is an underlying layer of graupel (frozen snow pellets) which act like ball bearings. But avoiding avalanches is an arcane art; see Avalanche expert killed in avalanche. Alansplodge (talk) 13:47, 10 August 2020 (UTC)
 * In this YouTube video the skier (as you suggest he ought) is just able to stay above the falling snow; however, one doesn't need to be Einstein to see that that particular slope was an avalanche waiting to happen and that it was a bit reckless to attempt a traverse. Alansplodge (talk) 13:55, 10 August 2020 (UTC)
 * I'm always amazed by the lack of perception of some skiers. Like the skier is already chancing it on that slope and then they traverse straight above a cornice. My recent favourite is this where the guy doesn't notice the massive cliff that spans the head of the valley. Zindor (talk) 21:56, 10 August 2020 (UTC)
 * Indeed. He was a lucky boy. Alansplodge (talk) 13:08, 11 August 2020 (UTC)