Avalanche Forecast
Issued: Apr 15th, 2021 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Cornices, Loose Wet and Deep Persistent Slabs.
JSmith,
Avalanche Canada
Sustained warming continues to increase the likelihood for large cornice failures and wet loose avalanches. Start early and plan to be off large slopes before the heat of the day.
Check out the latest Forecaster's Blog for more information on managing current conditions.
Summary
Confidence
Moderate - Uncertainty is due to how the snowpack will react to the forecast weather.
Weather Forecast
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THURSDAY NIGHT: Clear / Light, south ridgetop wind / alpine low temperature 2 / Freezing level 3000 m.
FRIDAY: Sunny / Light, southwest ridgetop wind / alpine high temperature 9 / Freezing level 3000 m.
SATURDAY: Sunny / Light, northwest ridgetop wind / alpine high temperature 8 / Freezing level 3000 m.
SUNDAY: Sunny / Moderate, east ridgetop wind / alpine high temperature 0 / Freezing level dropping to 1700 m.
Avalanche Summary
Over the last few days there were many small (size 1) wet loose avalanches on south-facing slopes at all elevations and a few size 2-2.5 cornice failures on north and east facing slopes.Â
The lower snowpack has been strong and settled over the past month, however, the dramatic warming this week could potentially wake up weak facets at the bottom of the snowpack. This is particularly a concern on steep, rocky slopes with a shallow or thin to thick snowpack. Cornice failures or a rider hitting a thin spot in the snowpack are the most likely ways to trigger these weak layers at the bottom of the snowpack.
Snowpack Summary
Lingering wind slabs may still be reactive in isolated locations on steep northerly aspects in the alpine. All other terrain is undergoing a melt-freeze cycle with successive days of warm sunny weather.Â
Strong solar radiation and warming will likely trigger the large cornices that hang over ridgelines. Cornice falls could trigger large avalanches on the slopes below.
The snowpack is overall strong and settled in most areas, however, sustained warming can increase the likelihood of large avalanches failing on deeply buried weak layers.This is most likely to occur on steep, rocky alpine slopes with a shallow or thin to thick snowpack.
Terrain and Travel
- Extra caution is needed around cornices under the current conditions.
- Avoid exposure to slopes that have cornices overhead.
- As surface loses cohesion due to melting, loose wet avalanches become common in steeper terrain.
- Back off slopes as the surface becomes moist or wet with rising temperatures.
- The likelihood of deep persistent slab avalanches will increase with each day of warm weather.
Problems
Cornices
Strong solar radiation and warming will likely trigger the large cornices that hang over ridgelines. Cornice falls could trigger large avalanches on the slopes below.
Aspects: North, North East, East, South East, North West.
Elevations: Alpine.
Likelihood
Expected Size
Loose Wet
Expect natural wet loose avalanches to occur on solar aspects when the sun comes out.
Aspects: East, South East, South, South West, West.
Elevations: All elevations.
Likelihood
Expected Size
Deep Persistent Slabs
Prolonged warming could increase the sensitivity of deeply buried layers in the snowpack. While these layers have not been reactive lately, you should practice increasing caution during this period of warm weather. Steep rocky terrain with a shallow or thin to thick snowpack are most suspect.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Apr 16th, 2021 4:00PM
