Avalanche Forecast
Issued: Dec 1st, 2021 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Storm Slabs.
wlewis,
Avalanche Canada
Storm slabs remain reactive with the greatest hazard in wind loaded terrain. Human triggered avalanches are still likely. Stick to simple terrain while the snowpack gains strength.
Summary
Confidence
Weather Forecast
After a final wave of moisture Wednesday night, freezing levels drop and cloudy skies return. The next round of precipitation arrives Saturday morning.
WEDNESDAY NIGHT: Another 5-10mm can be expected late afternoon and overnight, with winds still strong out of the southwest.
THURSDAY: Snowfall tapers off with up to 5cm expected over the day. Freezing levels lower to 1500m. Moderate westerly winds.
FRIDAY: Cloudy skies with no precipitation. Freezing levels at valley bottom and alpine highs of -10. Light winds from the northwest.
SATURDAY: Snow begins early Saturday morning bringing light to moderate accumulations over the day. Freezing levels remain below 1000m with moderate southwest winds.
Avalanche Summary
Observations over the last week show consistent direct-action avalanche cycles, where new snow and winds produce large natural avalanches at all elevations.
Tuesday November 30th saw numerous results from explosive work near Revelstoke. Skiers triggered avalanches to size 1.5 and explosives produced storm slab avalanches to size 2.5 above 1800m. A size 2.5 natural avalanche was observed in the Galena area in a southeast facing below treeline feature, producing wet debris.
On Monday, widespread natural cycles were observed to size 3 on steep terrain in the alpine and treeline.
On Sunday a widespread natural storm slab avalanche cycle was observed up to size 3 running to valley bottom along the Highway 1 corridor near Revelstoke. Explosive control work at alpine and treeline elevations produced storm slabs up to size 2.5, accumulating loose wet in the track and running full path.
Snowpack Summary
100mm of heavy snowfall and mixed precipitation over the last week have added a significant new load to the snowpack. Strong southwesterly winds have redistributed this load to create deeper deposits in lee features at treeline and above.
The mid-November crust is up to 5cm thick and found down 70-150cm with faceting below the crust. The lower snowpack contains several early season crusts which appear well bonded.
Snowpack depths exceed 300cm at treeline and alpine elevations, while below 1600m the snowpack decreases rapidly with elevation. At lower elevations, a mix of rain and snow has created a saturated upper snowpack.
Terrain and Travel
- Don't be too cavalier with decision making, storm slabs may remain sensitive to human triggering.
- Be especially cautious as you transition into wind affected terrain.
- Carefully monitor the bond between the new snow and old surface.
Problems
Storm Slabs
Storm slabs remain reactive to human triggers, the snowpack will take time to gain strength from a significant new load of snow, rain and wind. Use caution around wind effected terrain features and lee (wind loaded) slopes where triggering is more likely. Be wary of large slopes that have not avalanched.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Dec 2nd, 2021 4:00PM
