Avalanche Forecast
Issued: Dec 26th, 2020 8:00AM
The alpine rating is Wind Slabs and Persistent Slabs.
, the treeline rating is , and the below treeline rating is Known problems includeKate Ryan,
Although decreasing in likelihood, triggered persistent weak layers could result in avalanches running to valley bottom.
There is a Special Avalanche Warning in effect. Click Here to access.
Summary
Weather Forecast
A pacific frontal system will cross the BC interior today, gradually dissipating Sunday morning
Today: Mainly cloudy with isolated flurries (5cm). Alpine high -7 C. Wind SW 20-30 km/h
Tonight: Mainly cloudy with isolated flurries (5cm). Alpine low -9 C. Wind SW 30 km/h
Tomorrow: Cloudy with sunny periods, no precip. Alpine high -8 C. Wind W 10 km/h
Snowpack Summary
The recent storm dropped 120cm snow and was accompanied by warm temps and strong S-SW winds, followed by strong N winds. Weak layers: Dec 13 surface hoar/facets are down 70-110cm, Dec 7 crust/surface hoar layer is down 110-130cm+. The Nov 5 crust lingers near the base of the snowpack.
Avalanche Summary
Thursday, a skier accidental size 2 slab avalanche occurred in a SE Couloir on Mt Afton.
Wednesday, avalanche control by MOT produced two size 4 avalanches just west of the Glacier Park boundary. Bagheera SE face went size 3.5 overnight Wednesday. The suspected failure plane for these avalanches is the December 7th crust/ facet interface.
Confidence
Problems
Wind Slabs
120cm of storm snow in the past week with mild temperatures and strong S/SW winds. Post storm strong N'ly winds reverse loaded S'ly aspects too, expect slab formation on all aspects in the alpine and exposed areas of TL.
- If triggered the wind slabs may step down to deeper layers resulting in large avalanches.
- Keep an eye out for reverse loading created by N-NE winds earlier in the week.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Persistent Slabs
The Dec 7th surface hoar/crust and Dec 13th surface hoar layers have produced very large avalanches this past week, up to size 4! Wind slabs have the potential to step down to this layer.
- Be aware of the potential for wide propagations.
- Be wary of large alpine slopes that did not previously avalanche.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Dec 27th, 2020 8:00AM