The avalanche hazard remains heightened at upper elevations due to new snow, wind loading, and ongoing concerns about the deep persistent weak layers. Cool temperatures are also a concern. Be prepared to deal with the cold if anything unexpected occurs.
A combination of new snow and moderate to strong W-N winds have formed new wind slabs in lees areas of the alpine and treeline. In the past couple days these wind slabs have been reactive to skier traffic, and have failed naturally with ongoing wind loading.
The lower snowpack is comprised of weak facets and depth hoar with the upper snowpack forming a 40 to 90cm thick slab above the weakness. Not much has changed with this layer and human triggering remains a concern anywhere this weak layer is present.
Forecasters observed quite a few size 1-1.5 natural wind slab avalanches in the alpine over the past two days. Ski hills have also been triggering these wind slabs with explosives and ski cutting. A couple recent natural deep persistent avalanches up to size 2 in the alpine have also been observed over the past several days.
5-10 cm of new snow over the past few days with moderate to strong W-N winds are forming wind slabs at treeline and in the alpine. Below this, the upper snowpack contains weak layers 20-40 cm deep (Jan. 4th) and 30-60 cm deep (Dec. 17th) that are generally unreactive. The Nov 16 deep persistent layer is down 40-90 cm and continues to produce variable sudden test results. In areas west of the divide, the snowpack is more supportive than in eastern areas.
On Monday, expect moderate NW winds in the alpine with high temperatures between -15 to -20°C. Clouds will roll in with flurries beginning later in the day. Up to 5 cm is expected in areas near the divide. Continued cool temperatures on Tuesday before things slowly start warming through the week.
