Avalanche Forecast
Issued: Mar 1st, 2021 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Storm Slabs and Persistent Slabs.
swerner,
Avalanche Canada
Snowfall amounts vary across the region. If you see more than 25 cm in your local area bump the danger to HIGH. Natural avalanche activity may taper off but skier and rider triggering is likely. Its a good time to have a conservative mindset and stick to simple terrain.
Summary
Confidence
Weather Forecast
Monday Night: Snow 5-10 cm. Ridgetop wind strong from the southwest and alpine temperatures near -5. Freezing levels 300 m.
Tuesday: Snow 10-15 cm Ridgetop wind strong from the South and alpine temperatures near -3. Freezing levels 700 m.
Wednesday: Snow 20-30 cm. Ridgetop wind mostly light but gusty from the southwest. Alpine temperatures near -4 and freezing levels 700 m.
Thursday: Snow 15-20 cm. Ridgetop wind strong from the southwest. Alpine temperatures near -1 and freezing levels 900 m.
Avalanche Summary
Over the weekend a widespread natural avalanche cycle occurred up to size 3 and explosive control initiated numerous size 2-3 storm slabs and persistent slabs.
The storm continues and natural avalanche activity will likely occur through the forecast period.
It's a good time to stay very conservative, stick to simple terrain, and be aware of overhead hazards like large avalanche paths and cornices.
Snowpack Summary
40-60 cm of recent storm snow blanketed the region. This was accompanied by strong ton extreme southwest winds building deeper wind slabs on leeward slopes. Below 1000 m mixed precipitation of snow and rain likely fell leaving moist snow surfaces that are now refrozen.
This brings 90-250 cm over the plethora of old snow surfaces buried mid-February and deeper down buried late January. These lold layers comprise of hard wind-packed snow, feathery surface hoar crystals especially in areas sheltered from the wind, sugary faceted snow that developed during the cold snap, and a hard melt-freeze crust below treeline. These weak layers have been the result of several larger avalanches in the past week.
The mid-pack has been reported as being well-settled. There are presently no deeper concerns.
Terrain and Travel
- Potential for wide propagation exists, fresh slabs may rest on surface hoar, facets and/or crust.
- Use conservative route selection. Choose simple, low-angle, well-supported terrain with no overhead hazard.
- Shooting cracks, whumphs and recent avalanches are strong indicators of an unstable snowpack.
- Storm slabs in motion may step down to deeper layers resulting in large avalanches.
Problems
Storm Slabs
Up to 60 cm of new storm snow fell by Monday building touchy storm slabs. Natural avalanche activity may taper on Tuesday, however; conditions may be primed for skier and rider triggering. The wind is forecast to howl from the southwest, so wind slabs will rapidly build at upper elevations.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Persistent Slabs
The persistent slab has been reactive to rider and explosive triggering over the past few days. There is anywhere from 90 to 250 cm of snow above a mixed bag of old snow surfaces buried in mid-February. The concern now is for storm slab avalanches stepping down to this deep layer and skier or rider triggering which would result in a very-large, consequential avalanche.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Mar 2nd, 2021 4:00PM
