Avalanche Forecast
Issued: Dec 24th, 2020 3:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs, Deep Persistent Slabs and Cornices.
Mikey,
Avalanche Canada
Merry Christmas! Winds were strong on Thursday and we saw widespread new windslabs develop and in some places fail, triggering the deeper basal layers. These upper snowpack instabilities are definitely skier triggerable. Be conservative in your choices!
Summary
Confidence
High -
Weather Forecast
Well the winds were howling on Thursday but they are forecast to begin to back off a bit on Friday. Winds on Friday will be more moderate out of the SW with day time highs in the -6C range. No new precipitation is expected as we will be under the influence of a high pressure ridge until the 26th when we are expecting to get some new snow.Â
Avalanche Summary
A few large avalanches were observed over the past 24hrs failing down up to as much as 2m on the November crust. One of these large slides was likely triggered by a cornice collapse. In addition to these large events, there were numerous windslabs up to sz 2 failing in steeper alpine features mainly on N and E aspects.
Snowpack Summary
Strong winds is the main thing to talk about with regards to the snowpack. Winds over the past 24hrs have been strong out of the SW and most alpine areas have been highly affected. In some areas we are seeing windslabs overloading the basal November crust triggering large avalanches that are running to the valley floor. Expect to encounter windslabs at open areas at treeline and expect the windslabs to fail in steep or crossloaded areas down 40-60cm at the Dec 8th interface. Â
Terrain and Travel
- Avoid steep convex slopes.
- Back off steep and aggressive lines, stick to simple terrain.
- Continue to make conservative terrain choices while the storm snow settles and stabilizes.
Problems
Wind Slabs
Windslabs are widespread in alpine areas and in open areas down into treeline. Be aware of the potential for a upper snowpack instability to step down to the basal crusts.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Deep Persistent Slabs
We did see this as a failure recently, both natural and with explosives. This suggests we are in the hard, but not impossible to trigger phase.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Cornices
Cornices have been growing of late and failing triggerring avalanches on the underlying slopes
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Dec 25th, 2020 3:00PM
