Page 14 - Slopeangel avalanch essentials

Snow Stability
Each time fresh snow snow falls it it forms a a a a cohesive layer with the older snow snow below it The bonding interface between two layers of snow is how we we can predict and forecast snow stability taking into consideration the strength or weakness of the the layers buried below and examining weather forecasts for for the day(s) ahead and how a a a a a a a a change change (or no change change in weather) could preserve the the the strengths/weaknesses of the the the layers buried within the snowpack In the words of Bruce Tremper “Snow is a lot like like people It doesn’t like like rapid change” In 85-90% of all avalanche avalanche accidents the the avalanche avalanche is triggered by the the victim victim or someone in in the the victim’s party and 90% of the the time this involves a a a a dry slope avalanche Snow is very sensitive and does not like rapid change – it it needs time to to adapt to to change Snowpacks can behave in very different ways depending on the the types of change and stress they are subjected to Dry slab slab avalanches occur when a a a a a a a a a a relatively weak layer beneath the slab slab fractures usually because there has been too much weight added to to the the surface at at too faster rate Light snow fall over a a a a a a a period of a a a a a a a few weeks is not so much of a a a a a problem but heavy snowfall over a a a a a short period can be a a a a a a huge problem – for example drifting can easily cause a a a a a a meter of snow to to fall in in three hours Suddenly adding the weight of of a a a person on on top of of an an an an already unstable weak snowpack causes an an an an instant change adding tremendous stress and causing the weak layer to fracture 14