Avalanche Forecast
Issued: Feb 20th, 2022 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Storm Slabs and Cornices.
zryan,
Avalanche Canada
The north of the region was a hot spot for Saturday's storm. Continue to be conservative with terrain choices as storm slabs may still be reactive to human-triggering.
In the south of the region, the problem is likely more confined to a wind slab problem in lee areas.
Summary
Confidence
Weather Forecast
Bundle up in your warmest gear, arctic air is here!
Sunday Overnight: Cloudy with light flurries, clearing into the morning. Light to moderate northerly winds. Alpine temperatures plummet to around -20 C.
Monday: Partially cloudy and cold. Light northerly winds. Alpine temperatures around -20 C.
Tuesday: Cold and clear. Light northerly winds. Alpine temperatures around -20 C.
Wednesday: Cloudy with light flurries. Light to moderate northwesterly winds. Alpine temperatures around -16 C.
Avalanche Summary
In the north of the region, a natural cycle likely occurred during the peak of the storm on Saturday afternoon. Numerous human-triggered storm and wind slabs were reported throughout the day. In the south of the region, wind slabs were reactive to human triggering, with natural loose dry avalanches observed out of steep terrain in the alpine.
Explosive control last week initiated some larger persistent slabs up to size 3 on north-facing aspects at treeline.
Snowpack Summary
This weekend's storm brought 20-70 cm of new snow, with up to 100 cm now overlying the old, hard surface. This surface is a result of a period of high pressure in mid-February. The layer is comprised of facetted snow, a melt-freeze crust at lower elevations, a sun-crust on steep solar aspects, and hard wind-affected snow in the alpine and exposed treeline.
The mid-January surface hoar/crust layer is now down 50-150 cm in the snowpack. This layer has not been reactive to skier traffic in the past week and is showing limited reactivity in snowpack tests. Although unlikely, the layer could be triggered from a large load like a cornice fall or a shallower slab avalanche stepping down to this layer.
The facet/crust layer that formed in early December is now buried around 150 to 250 cm. Human triggering of this layer is unlikely, except perhaps on a re-loaded bed surface or in a shallow snowpack area. This layer may become a concern during periods of warming or heavy loading.
Terrain and Travel
- Be especially cautious as you transition into wind affected terrain.
- Use small low consequence slopes to test the bond of the new snow.
- Shooting cracks, whumphs and recent avalanches are strong indicators of an unstable snowpack.
- Minimize exposure to sun-exposed slopes when the solar radiation is strong.
- Avoid exposure to overhead hazards when solar radiation is strong.
Problems
Storm Slabs
This weekend's storm brought 15-100 cm of storm snow which overlies the February 15th drought layer.
The south of the region received less snowfall and the problem is likely more confined to a wind slab problem. 15-30 cm of recent storm snow has been redistributed by southwest winds into wind slabs in lee areas.
In the north of the region, cold temperatures may help to decrease the reactivity of the more widespread storm slab problem, but deeper, and stiffer slabs will exist in wind-loaded terrain, which probably remain reactive to human-triggering.
Do not underestimate the influence of solar radiation on these cold days! Reactivity could increase rapidly on sun-exposed slopes when solar radiation is strong.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Cornices
Cornices may have grown significantly with wind and snowfall over the past 3 days. Be especially mindful of overhead cornice hazard if the sun comes out and the storm snow is experiencing strong solar radiation for the first time.
Aspects: North, North East, East, South East, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Feb 21st, 2022 4:00PM
