Avalanche Forecast
Issued: Dec 27th, 2020 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs, Persistent Slabs and Deep Persistent Slabs.
mark herbison,
The snowpack is complex and has a great deal of variability throughout the region. Assess the snowpack locally before committing to your line and consider what looms overhead if climbing in exposed terrain.
Happy Holidays!
Summary
Weather Forecast
Monday will see a mix of sun and cloud with isolated flurries accumulating 1-2 cm of snow. Temps will range from -6 to -13 as the winds will remain light,10-25 km/hr from the West. Sunny with light winds for Tuesday.
Snowpack Summary
Small amounts of new snow now bury wind slabs created by recent 25-45km/hr SW-W winds redistributing the 30-60cm of snow from the past week. The Dec 13 and Dec 7 sun crust/surface hoar/facet layers are down ~ 50cm and ~80 cm respectively. The decomposing Nov crust/facets sits at the bottom of the snowpack. Height of snow at tree line is 120-170cm.
Avalanche Summary
No new avalanche observations or reports on Friday.
Local ski areas reporting small, thin wind slabs on NE aspects, triggered by explosives.
Confidence
Problems
Wind Slabs
Wind slabs were formed by strong SW-W winds Wednesday through Friday. While these have become buried with new snow, expect to find small, spotty slabs as you enter open areas at Tree Line and to encounter more developed slabs in the Alpine.
- If triggered the wind slabs may step down to deeper layers resulting in large avalanches.
- Watch for shooting cracks or stiffer feeling snow. Avoid areas that appear wind loaded.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Persistent Slabs
There are a variety of weaker layers down 50-80cm at tree line, the Dec 7 and 13th layers of facets, suncrust, and isolated surface hoar. These layers deserve constant suspicion as they can change quickly from one aspect to another.
- Dig down to find and test weak layers before committing to a line.
Aspects: All aspects.
Elevations: Treeline.
Likelihood
Expected Size
Deep Persistent Slabs
We have had a few observations of avalanches stepping down to the Nov. 5 crust and facets. This is a problem with higher uncertainty, and is most prevalent in shallow snowpack areas where the layer has weakened over time.
- Be cautious in shallow snowpack areas where triggering is more likely.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Dec 28th, 2020 4:00PM
