Avalanche Forecast
Issued: Nov 28th, 2021 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Storm Slabs.
ahanna,
Avalanche Canada
Storm slabs are likely to remain reactive Monday due to an upside-down configuration in the upper snowpack and sustained warm temperatures. Continue to make conservative terrain choices at this time.
Summary
Confidence
Low - Uncertainties in both the snowpack structure and the weather forecast limit our confidence.
Weather Forecast
Sunday night: Flurries, 5-10 cm. Moderate southwest wind. Freezing level 2000 m.Â
Monday: Flurries, up to 5 cm. Moderate southwest wind. Alpine temperature around 0 C. Freezing level 2000 m.
Tuesday: Flurries, up to 5 cm. Moderate to strong southwest wind. Alpine temperature around -2 C. Freezing level 1800 m.
Wednesday: Wet snow and rain, 10-25 mm. Moderate southwest wind. Alpine temperature high +2 C. Freezing level 2400 m.
Avalanche Summary
Several natural storm slab avalanches were observed in the alpine on Sunday, a few notably stepping down to deeper layers (suspect the mid November crust).
A natural avalanche cycle occurred overnight Thursday-Friday, large storm slab avalanches (size 2-2.5) in alpine and upper treeline features were reported Friday morning. Through the day, explosives triggered large (size 2) storm slab avalanches.
Snowpack Summary
The upside-down upper snowpack consists of a 10-15 cm heavy, wet cap sitting over about 40 cm of lower density snow. Below lies a thick mid-November rain crust which has been the suspected bed surface of a few recent step-down avalanches. Moist snow is still found below the crust and to the ground.
Snowpack depths range from 40-70 cm at treeline elevations. Expect to find a deeper snowpack at higher elevations and in wind-loaded areas. Snowpack depths decrease rapidly below 1500 m.
Terrain and Travel
- Good day to make conservative terrain choices.
- Be aware of the potential for large avalanches due to the presence of a buried crust.
- Avoid lingering or regrouping in runout zones.
Problems
Storm Slabs
Storm slabs are likely to remain reactive Monday amidst sustained warm temperatures. Heavy, wet storm slabs sitting on top of lower density snow may also result in step-downs to the mid November crust.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Nov 29th, 2021 4:00PM
