Pro Field Report

Observation Details

Signs of Unstable Snow

Seeing signs of unstable snow in isolated areas where the light snow has deposited on lee slopes and mountain valleys protected by high winds, specifically cross loaded slopes. On 5 Feb I noticed a collapse in the upper weak layers while i was cooling my sled by laying on its side and slowly grinding the track into the snowpack bringing snow through the tunnel and exiting past the track drivers. As the snow exited and lightly piled up on top of the untouched snow, I noticed a significant collapse in about a three-foot square area! I found this quite interesting and will take it as a warning of how the next storm cycle will add stress as it buries this weak layer found throughout the top foot or so of the snowpack. Today I watched as a sledder dropped a cornice causing the cornice to fall triggering an avalanche chasing him down the hill. The snowpack consisted of a wind slab on top of near surface facets and a couple buried layers of surface hoar.

Snow Stability

Bottom Line

Generally, the snowpack is very strong. I'm finding facetted layers near the ground in shallow snowpack areas and widespread near surface facets along with buried surface hoar layers in the top of 10 to 20 inches of the snowpack. Additionally, there are isolated wind loaded slopes causing wind slabs on top of this extremely weak and fragile layer. For now, we don't have widespread areas with heavy loading, so the hazard risk is relatively low. On longer slopes, perhaps with additional cross loading caused by changing wind directions in recent days, a thin layer of snow releasing from a large area can create a big enough pile of snow to bury a rider and could be deadly if this occurred in a terrain trap.