By: Marlene Affeld
Have you ever witnessed an avalanche? They are awesome, terrifying and among the greatest dangers to human life that one may encounter in the back country. In the United States, over the past ten years there has been an average of 25 avalanche fatalities per year. The majority of avalanches affecting people are triggered by people. Skiers, snowmobilers and everyone that travels in avalanche-prone areas should remain vigilant and aware.
An avalanche is a rapid and abrupt mass flow of snow, generally mixed with water and air that thunders down the mountainside, burying anything in its pathway. Typically avalanches are caused by an over-burden of snowpack that is too massive and unstable for the slope that supports it. As an avalanche crashes down the mountain it will also tear loose trees, rocks and boulders that become part of the devastating barrage.
It is extremely dangerous in the mountains when a period of very cold weather is followed by a chinook or sudden warming trend or when rain is falling on snow pack. Free flowing water in the snow pack lubricates weak or fragile layers of the snow and often massive avalanches result. Like intense snowstorms, this is a very dangerous time to be traveling in the mountains.