Avalanche Forecast
Issued: Dec 14th, 2020 4:22PM
The alpine rating is Wind Slabs, Loose Dry and Deep Persistent Slabs.
, the treeline rating is , and the below treeline rating is Known problems includeAaron Beardmore,
Wind and new snow are approaching the forecast region. Expect to see wind slab development in the alpine. Continue to watch for sluffing of surface snow in steep terrain, especially steep gullies.
Summary
Weather Forecast
The wind is supposed to pick up to the strong range on Tuesday, from the SW. Temperatures will remain steady at -15 at the ridge and about -10 in the valley. Snow is expected to start midday Tuesday and continue through until Thursday, the amount totaling about 20cm over the 3 days.
Snowpack Summary
Up to 20cm of new snow and light wind effect in the alpine. 20-40 cm of snow sits on the Dec 7th layer of sun crust, facets or surface hoar depending on your location. The Nov. 5th crust / facet layer persists at the bottom of the snowpack and continues to weaken over time. Snowpack depths are 90-160cm at tree line.
Avalanche Summary
A dry loose avalanche left a deposit 2.5m deep on Super Bok today. The avalanche was likely a size 1 or 1.5 but the deep deposit was due to a substantial terrain trap. Cool spring also had a deposit resulting from a size 1.5 avalanche, again, into a terrain trap. ACMG guides reported a very small surface slab 5cm deep and 5m wide on Mt. Field.
Confidence
Problems
Wind Slabs
With forecasted strong wind from the SW on Tuesday there is a high likelihood that new wind slabs will start forming. Up to 20cm of low density snow is currently available for redistribution in Little Yoho, with more on the way.
- Be careful with wind loaded pockets, especially near ridge crests and roll-overs.
Aspects: North, North East, East, South East, South, North West.
Elevations: Alpine.
Likelihood
Expected Size
Loose Dry
20-40 cm of recent snow is now faceted. In steep terrain, wind or people can start a small avalanche in the surface snow that will run far on the layer of facets, sun crust or surface hoar underneath it. New snow on Tues will add to this problem.
- Be careful of loose dry power sluffing in steep terrain.
- Be cautious with gully features.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Deep Persistent Slabs
The Nov 5 crust has facets above and below it, and exists up to 2500m on shady aspects and higher on solar aspects. We have only had isolated observations of a deep slab avalanches since the storm, but it is still on our minds in shallow areas.
- Be aware of thin areas that may propogate to deeper instabilites.
- Pay attention to overhead hazards like cornices which could trigger the deep persistent slab.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Dec 15th, 2020 4:00PM