Wet loose avalanche release is driven by which condition?

• A. Release of dry, unconsolidated snow
• B. Release of meltwater between layers
• C. Release of wet/unconsolidated snow warmed by sun, rain, etc
• D. Release of wind slab

Answer: (C)

Wet loose avalanches happen when the surface snow becomes wet and loses strength because of liquid water in the snowpack. Solar warming, rain, or a thaw saturates the top layer, turning the upper few inches into a slushy, low‑friction mass. This makes the snow highly mobile: a small disturbance can start a flow that begins at a single point and then fans out downslope as it travels, carrying wetter, unconsolidated snow with it. The key idea is that the driving factor is surface wetting from sun and precipitation, which creates a loose, exposed layer that can flow freely.

By contrast, dry loose avalanches are triggered in dry, unconsolidated snow, and wind slabs form from wind‑deposited, cohesive layers rather than wet surface saturation. Meltwater between layers can promote other types of instability, but the characteristic wet loose release is specifically driven by surface snow that has been warmed and wetted.