Which of the following is a predictor?

• A. Rapid and recent snowfall
• B. Dry spell with no thaw
• C. Surface crust formation
• D. Stable soil moisture

Answer: (A)

Rapid and recent snowfall is a predictor because avalanches occur when the snowpack becomes unstable under added weight. When a lot of snow falls quickly, it loads the layers beneath faster than they can bonding and restructure, creating fresh slabs over weaker, older layers. This combination makes the snowpack much more prone to failure when tapped by a trigger, so the danger level rises soon after a heavy snowfall event.

A dry spell with no thaw reduces new loading, so it doesn’t signal an immediate increase in avalanche risk. Surface crust formation can influence stability by creating weak interfaces, but on its own it’s not as direct an predictor of an imminent avalanche as fresh snowfall. Stable soil moisture isn’t related to snowpack stability and doesn’t indicate avalanche threat.