Avalanche Forecast
Issued: Mar 12th, 2021 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Cornices, Loose Wet and Wind Slabs.
JSmith,
Avalanche Canada
Things are looking HOT up high for the next couple days. Overhead hazards such as cornice failures and wet loose avalanches on large alpine slopes will be the primary concern. Pay attention to what's above your head and back off of slopes if the snow surface becomes moist.
Summary
Confidence
Moderate - Uncertainty is due to how the snowpack will react to the forecast weather.
Weather Forecast
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FRIDAY NIGHT: Partly cloudy / Moderate, southwest ridgetop wind / alpine low temperature -11 / Freezing level 1000 m.
SATURDAY: Sunny / Moderate, southwest ridgetop wind / alpine high temperature 2 / Freezing level rapidly rising to 2200 m. and remaining elevated overnight.
SUNDAY: Sunny / Strong, south ridgetop wind / alpine high temperature 2 / Freezing level 2100 m.
MONDAY: Mix of sun and cloud / Light, northwest ridgetop wind / alpine high temperature 0 / Freezing level 1700 m.
Avalanche Summary
No avalanches were reported in this region on Thursday. However, the rapidly rising freezing level and sunny skies on Saturday are expected to elevate the avalanche hazard through the weekend.
Snowpack Summary
5-10 cm. of dry snow overlies a crust on shady aspects, except in the northwest of the region where convective squalls have deposited up to 20 cm. of recent snow. The convective nature of spring storms results in widely varying snowfall amounts. Crusty snow surfaces exist on solar aspects. Pockets of old wind slabs may exist in isolated locations below alpine ridgelines. Large cornices are present along ridgelines.
A persistent weak layer made up of surface hoar at treeline elevations and a crust with facets in the alpine on solar aspects can be found down 50-150 cm. in some parts of the region. No recent avalanches have been reported on these layers. However, big warm ups, like the one headed our way this weekend can awaken dormant weak layers resulting in large avalanches. Steep, rocky, convex terrain with a shallow or thin to thick snowpack are examples of places where triggering these layers are more likely.
Sunshine and warm temperatures often cause large cornice failures which are hazardous on their own and can also trigger large avalanches on deeper weak layers that the weight of a single rider would not trigger.
Terrain and Travel
- Avoid exposure to slopes that have cornices overhead.
- Cornice failure may trigger large avalanches.
- Back off slopes as the surface becomes moist or wet with rising temperatures.
- Avoid steep, rocky, and wind effected areas where triggering slabs is more likely.
Problems
Cornices
Rapidly rising freezing levels and sunny skies significantly increase the likelihood of cornice failures which are hazardous on their own and can also trigger large avalanches on deeper weak layers that the weight of a single rider would not trigger. Avoid exposure to slopes that have cornices overhead.
Aspects: North, North East, East, South East, North West.
Elevations: Alpine.
Likelihood
Expected Size
Loose Wet
Naturally triggered wet loose avalanches are likely, especially on steep solar aspects in the alpine.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Wind Slabs
Recent convective flurries in parts of the region, solar radiation, and light to moderate winds may have formed reactive slabs in isolated alpine locations. Steep, convex slopes below alpine ridgetops are the most likely places to trigger these slabs.
Aspects: All aspects.
Elevations: Alpine.
Likelihood
Expected Size
Valid until: Mar 13th, 2021 4:00PM
