Avalanche Forecast
Issued: Apr 23rd, 2023 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Storm Slabs, Deep Persistent Slabs and Cornices.
jsmith,
Avalanche Canada
Forecast snow and strong southerly wind are expected to form fresh storm slabs reactive to human triggers.
Numerous very large deep persistent slab avalanches have been reported on a variety of aspects in the alpine.
Summary
Confidence
Avalanche Summary
No avalanches were reported on Saturday. However, observations in this region are currently very limited.
Numerous naturally triggered very large (up to size 3.5) deep persistent slab avalanches were reported on a variety of aspects in the alpine on Friday. They failed on either a crust/facet layer 100+cm deep or weak facets at the bottom of the snowpack. Follow the link on this MIN for the photos of these notable avalanches.
Observations are limited at this time of year, please consider sharing any information or photos you have on the Mountain Information Network to help guide our forecasts.
Snowpack Summary
Forecast snow and strong southerly wind are expected to form fresh storm slabs reactive to human triggers.
A weak layer of crust/facets down 100+ cm and/or weak facets at the bottom of the snowpack have recently become reactive.
Cornices are large and loom over slopes below like gargoyles.
Weather Summary
Sunday Night
Snow; 10-20 cm / 40 km/h southeast ridgetop wind / Temperature at treeline around -4 C / Freezing level 500 m
Monday
Mostly cloudy with flurries; 5-10 cm / 30 km/h south ridgetop wind / Temperature at treeline around -2 C / Freezing level 700 m
Tuesday
Mix of sun and cloud / 25 km/h south ridgetop wind / Temperature at treeline around -2 C / Freezing level 700 m
Wednesday
Mostly cloudy with flurries; 5-10 cm / 30 km/h southeast ridgetop wind / Temperature at treeline around 0 C / Freezing level 1000 m
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Storm snow and wind is forming touchy slabs. Use caution in lee areas in the alpine and treeline.
- Watch for signs of instability like whumpfing, hollow sounds, shooting cracks or recent avalanches.
- If triggered, storm slabs in-motion may step down to deeper layers and result in very large avalanches.
- In areas where deep persistent slabs may exist, avoid shallow or variable depth snowpacks and unsupported terrain features.
- Cornice failure may trigger large avalanches.
Problems
Storm Slabs
Forecast snow and strong southerly wind are expected to form fresh storm slabs reactive to human triggers.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Deep Persistent Slabs
A weak layer of crust/facets down 100+ cm and/or weak facets at the bottom of the snowpack have recently become reactive.
Snowpack and avalanche observation data are currently very limited in this region which makes this kind of avalanche problem very difficult to forecast.
Aspects: All aspects.
Elevations: Alpine.
Likelihood
Expected Size
Cornices
Cornices are very large and loom over slopes below like gargoyles. Cornice falls may trigger large avalanches on the slopes below.
Aspects: North, North East, East, North West.
Elevations: Alpine.
Likelihood
Expected Size
Valid until: Apr 24th, 2023 4:00PM
