Avalanche Forecast
Issued: Mar 7th, 2021 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs, Cornices and Loose Wet.
astclair,
Avalanche Canada
Sunny skies and rising temperatures may initiate wet loose activity on lower elevation and/or sun-exposed slopes. Steer clear of cornices and wind-drifted areas as they have the potential to produce large avalanches.
Summary
Confidence
Weather Forecast
Dry conditions for the next few days
Sunday night: Mostly cloudy, scattered flurries with up to 5 cm of snow, light southeast wind, freezing level dropping to valley bottom.
Monday: Mainly sunny, light east wind, freezing level rising to 1400 m and dropping to valley bottom overnight.
Tuesday: Mix of sun and cloud, light variable wind, freezing level rising to 1400 m and dropping to valley bottom overnight.
Wednesday: Sunny, light north wind, freezing level rising to 1400 m and dropping to valley bottom overnight.
Avalanche Summary
Explosive mitigation on Saturday produced numerous large cornice and storm slab avalanches, with 50-100 cm crown depths. Explosives also released a very large (size 3) wind slab avalanche on a northeast aspect above 2000 m.
Reports indicate that a natural avalanche cycle occurred during the storm on Friday, with small to large (size 1-2.5) avalanches releasing in the storm snow across aspects and elevations. See this MIN report for an example from Hanging Lake.
Snowpack Summary
50-100 cm of snow accumulated over the weekend, and it is settling rapidly. The recent snowfall was accompanied by strong south winds, forming wind slabs on leeward slopes that may be likely to trigger. Massive cornices exist on ridgelines, which can act as triggers on slopes below. Rising temperatures and strong sun on Monday is expected to destabilize cornices and recent snow. Watch for signs that the snow is rapidly warming, such as pinwheels, rollerballs, and point releases.
In isolated areas with a shallower snowpack in the region, a layer of facets, spotty surface hoar, and/or crusts buried in mid-February may still be preserved. There have been no avalanches reported on this layer; however, large triggers, such as an avalanche in motion, cornice fall have the potential to trigger this deeper layer in areas where it may still exist.
The mid and lower snowpack is well settled and strong in most areas.
Terrain and Travel
- Stay off recently wind loaded slopes until they have had a chance to stabilize.
- Avoid freshly wind loaded features, especially near ridge crests, roll-overs and in steep terrain.
- Cornice failure may trigger large avalanches.
- As surface loses cohesion due to melting, loose wet avalanches become common in steeper terrain.
Problems
Wind Slabs
Strong south winds have had ample snow to drift into reactive wind slabs on lee features at upper elevations. Watch for cracking, changes in snow stiffness, and the pattern of wind-drifting in the terrain where you are traveling. Triggering large wind slabs on specific features remains likely on Monday.
Aspects: North, North East, East, South East, West, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Cornices
Cornices have seen substantial growth since the last storm, and they may release naturally with the impact of solar radiation. Cornice falls can act as triggers on slopes below.
Aspects: All aspects.
Elevations: Alpine.
Likelihood
Expected Size
Loose Wet
Wet loose avalanches may release naturally on low elevation or steep sun-exposed slopes. A wet snow surface, pinwheeling or loose wet point releases out of the rocks are good indicators that it is time to back off.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Mar 8th, 2021 4:00PM
