Quick report
- Red Flags
- Recent Avalanches, Wind Loading, Poor Snowpack Structure
The graupel that fell overnight and today is loose and sitting on top of denser snow, and I think it may be a weak layer with this incoming storm. But there are other weak layers throughout our snowpack, and if this storm delivers over another inch of water, it is possible avalanches may fail more deeply. In the video below, I describe some of these possible weaknesses.
Snowpack
- Instability Comment
- <p>Although most wind drifts were unreactive to quick stability tests, I did get an ECTV (fracture and propagation on isolation) on a recently wind-loaded slope facing west that was cross-loaded. Widespread wind drifts along northerly-facing aspects with some small cornice development. There is plenty of snow available for transport, and with increasing winds overnight and into Monday, I expect more fresh wind drifts. </p> <p>The three avalanches in Hidden Canyon in the Brighton backcountry are a reminder that - on the right slope - it is possible to trigger an avalanche failing 60-90 cms (2-3+ feet) deep. What is the right slope? With such spatial variability of the thickness of the Christmas Rain Crust (CERC) and no clear patterns, this is hard to tell. With more snow/water and wind on the way, some slopes that haven't yet avalanched on the PWL may be more susceptible.</p>
Roughly 10 cms (3-4 inches) of graupel which made for excellent travel and riding conditions. Rain/Snow line was 7,500 feet in the morning, though lowered to about 7,000 feet late afternoon.
Photo of graupel and rimed crystals.