Avalanche Forecast
Issued: Apr 12th, 2021 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Loose Wet, Cornices and Wind Slabs.
kdevine,
Avalanche Canada
Sunny weather and warm temperatures will increase the likelihood of wet loose avalanches on sun-exposed slopes, and cornice failure. Expect to find pockets of wind slab at upper elevations, which may be reactive to human triggers.
Summary
Confidence
Moderate - Uncertainty is due to how the snowpack will react to the forecast weather.
Weather Forecast
A ridge of high pressure, with sunny skies and high freezing levels will dominate the weather pattern this week.
Monday night - Mainly clear / moderate northeast wind / alpine low temperature near -7 / freezing level 800 mÂ
Tuesday - Sunny / light to moderate northeast wind / alpine high temperature near -1 / freezing level 2200 mÂ
Wednesday - Sunny / moderate northeast wind / alpine high temperature near 2 / freezing level 2600 mÂ
Thursday - Sunny / light northeast wind / alpine high temperature near 3 / freezing level 2600 m
Avalanche Summary
There have been several size 1-2.5 natural and human triggered storm and wind slab avalanches reported over the past few days. These were mainly on northerly aspects in the alpine and at treeline. There have also been several cornice failures, and small wet loose avalanches reported.
Looking forward, wind slabs are still possible to trigger at upper elevations, and wet loose avalanches are expected with sun and warm temperatures. The likelihood of cornice failure also increases with warming.
Snowpack Summary
A storm late last week brought between 10-20 cm of new snow in the north, and 20-30 cm near the Coquihalla. The new snow fell on a crust in many areas, and was very reactive.
The snow surface is now likely a crust in most areas, except on north aspects above about 1400 m where both soft snow and wind slabs may exist. In areas where the surface is a crust, sunshine and rising freezing levels are expected to soften the crust during the day.
Cornices are large and looming along ridgelines. Their release is unpredictable but increases in likelihood with daytime warming, requiring a large berth if you're travelling above or below them.
Terrain and Travel
- Avoid sun exposed slopes, especially if snow surface is moist or wet.
- Loose avalanches may start small but they can grow and push you into dangerous terrain.
- Pay attention to cornices and give them a wide berth when traveling on or below ridges.
- Watch for wind-loaded pockets especially around ridgecrest and in extreme terrain.
Problems
Loose Wet
Surface snow will lose cohesion and become unstable with sun and rising temperatures during the day. Avoid exposing yourself to terrain where a small wet loose avalanche could have big consequences.
Aspects: South East, South, South West, West.
Elevations: All elevations.
Likelihood
Expected Size
Cornices
Cornices are large and looming along many ridgelines. They grow increasingly unstable during periods of warming.
Aspects: North, North East, East, West, North West.
Elevations: Alpine.
Likelihood
Expected Size
Wind Slabs
Isolated wind slabs may still react to human triggering in steep features at ridgecrest.
Aspects: All aspects.
Elevations: Alpine.
Likelihood
Expected Size
Valid until: Apr 13th, 2021 4:00PM
