Avalanche Forecast
Issued: Dec 27th, 2013 7:53AM
The alpine rating is Storm Slabs, Persistent Slabs and Deep Persistent Slabs.
, the treeline rating is , and the below treeline rating is Known problems includeSummary
Confidence
Fair - Due to the number of field observations
Weather Forecast
Saturday: Mainly cloudy with a chance of flurries and possible sunny breaks. The freezing level drops to valley bottom and winds are light to moderate from the northwest. Sunday: Mainly cloudy with a chance of flurries or light snow â around 5 cm. The freezing level is near valley bottom and winds are moderate gusting strong from the W-NW. Monday: Flurries or periods of snow. The freezing level should remain at valley bottom.
Avalanche Summary
Reports from the past couple days are very limited. It's likely that the combination of new snow, wind, and mild temperatures kicked off a natural avalanche cycle in some areas over the past couple days. The additional load may have also been enough to trigger deep persistent weaknesses in isolated areas. Cooler temperatures and drier conditions on the weekend should help to stabilize the snowpack, but rider triggering will certainly remain a concern. Watch for steep slopes that did not previously avalanche, wind loaded areas, and high north-facing terrain with variable snow cover.
Snowpack Summary
An additional 20-30 cm of snow has fallen accompanied by moderate to strong W-SW winds and mild temperatures. New dense wind slabs are likely in exposed lee terrain at and above treeline. Up to 80cm of snow now sits on a variety of weaknesses from early December (surface hoar, faceted snow, and/or a crust). An older layer of surface hoar or facets from late November can be found deeper in the snowpack. Recent snowpack tests results vary but some are showing this layer "pop" with medium loads, indicating a potential for human triggering.Snowpack depths vary, but in general up to 150 cm of snow can be found at treeline, with 100-200 cm in the alpine. In many places we're still dealing with a relatively thin snowpack (thanks to a windy early season) so there's not a whole lot of snow between riders and the sugary snow (facets) near the ground. The basal facet/crust combo has been recently active in parts of the region.
Problems
Storm Slabs
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Persistent Slabs
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Deep Persistent Slabs
Aspects: North, North East, East, South East, South.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Dec 28th, 2013 2:00PM