Avalanche Forecast
Issued: Apr 27th, 2023 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Deep Persistent Slabs, Cornices and Loose Wet.
GS,
Avalanche Canada
A major avalanche cycle will begin on Friday and last through the weekend. Avoid all avalanche terrain and pass this message along to your friends who go hiking. Avalanches will run to the valley bottom. Mt. Stephen, Mt. Field, Mt. Cathedral and Mt. Hector avalanche zones are closed on Friday for avalanche control.
Summary
Confidence
Avalanche Summary
No significant avalanches were reported on Thursday as of 3:00 pm. The snow surface was frozen on Thursday morning and was isothermal by 1:00 pm. Some small wet loose sluffs were observed, but the heat of the day is upon us now until later this evening.
Snowpack Summary
The weak snowpack we've been warning about all winter is about to get a major test, as sky-high freezing levels will destabilize the snowpack during the day, with no refreezing expected overnight for Saturday and Sunday. Expect wet, sloppy snow on all aspects and elevations and isothermal snow (slush) at the treeline and below. We expect many large avalanches to fail on the ground.
Weather Summary
A ridge of high pressure establishes itself over the region today, bringing the first hot period of spring. Freezing levels on Saturday could reach up to 3500 m with sunny skies. Valley bottom high temperatures will reach 17 degrees on Friday and 20 degrees on Saturday. Major change underway.
Terrain and Travel Advice
- Avoid all avalanche terrain during periods of intense solar radiation.
- Avoid exposure to overhead avalanche terrain as temperatures increase.
Problems
Deep Persistent Slabs
This dangerous problem results from a weak snowpack base formed in early winter, now with the entire winter's snowpack above it. This problem has been difficult to predict, except this weekend when we're almost certain to see many large avalanches.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Cornices
Cornices will fall off this weekend for sure. With the high freezing levels and direct sun exposure, the mountains will begin to shed. Do not exposure yourself below or close to any corniced features.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Loose Wet
We expect wet snow avalanches on all aspects and elevations, especially when the sun cooks the slopes. Slush and wet snow will run like water down gullies and through rock bands: the spring melt is on.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Apr 28th, 2023 4:00PM
