Technical information, news, research, and opinion on avalanches, snow safety, and winter backcountry travel.

Sunday, November 15, 2009

Elements Of Instability

There's gun in your hand and it's pointing at your head—Pet Shop Boys

NOTE: Backcountry avalanche forecasting is composed of four interconnected elements: goal, people, awareness, and uncertainty. The elements of instability are linked to awareness and uncertainty—maintaining awareness and managing uncertainty are central tools for helping people successfully accomplish the goal of backcountry avalanche forecasting.


Forming an accurate perception of instability is the goal of backcountry avalanche forecasting. In simple terms, your perception of instability should match reality as closely as possible.

What exactly does instability mean? Let's answer this question with a question: what do you believe about weaknesses in the snowpack and the energy required to trigger avalanches?

Weaknesses & Triggers

From the perspective of backcountry avalanche forecasting, instability revolves around weaknesses and triggers. It is helpful to think about both of these elements on a scale because weaknesses may range from very rare to very frequent, and the triggering energy required to release avalanches may range from very low to very high.

Figure 1.1. Distribution of weaknesses could range from very rare to very frequent.

Figure 1.2. Triggering energy required to release avalanches could range from high triggering energy to low triggering energy.

Do you believe weaknesses are widespread and avalanches easily triggered? Or do you believe weaknesses are located near certain terrain features and difficult to trigger? Your beliefs about instability can refer to an entire season, a whole day, a specific hour, or a span of just a few minutes. Therefore, your beliefs about instability are not constant, and in fact, it is best practise to regularly update your beliefs about instability.

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