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 Wind Slabs.
cgarritty,
Avalanche Canada
Unprecedented early season storms demand an extra conservative approach to mountain travel. This is a time to measure your exposure to avalanche terrain extremely carefully. Soon it will be time to avoid it entirely.
Summary
Confidence
Weather Forecast
Sunday night: Cloudy with lingering flurries bringing about 5 cm of new snow. Potential for localized enhanced accumulations. Moderate to strong west winds.
Monday: Mainly cloudy with isolated flurries. Moderate west wind shifting southwest and increasing in the afternoon. Treeline high temperatures around +4.
Tuesday: Cloudy with flurries increasing from the overnight period and bringing 10-15 cm of new snow, increasing again overnight. Strong southwest winds. Treeline high temperatiures around 0 as freezing levels rise from 1400 to 1900 metres over the day.
Wednesday: Cloudy with continuing snowfall bringing 20-40 cm of new snow and storm totals to 30-55cm. Moderate southwest winds. Treeline high temperatures around -1 with freezing levels around 1700-1800 metres.
Avalanche Summary
Just east of the forecast region on Wednesday, a size 2 slab avalanche in a wind-loaded alpine feature was reported on the Mountain Information Network. See here for more information.
The North Rockies field team was riding west of McBride on Wednesday as well. They found isolated wind slabs 15-25 cm deep in lee slopes with the potential to produce small avalanches (see MIN post here).
The consistent storm pattern has given the snowpack little time to stabilize between snowfalls, which means similar conditions will likely prevail on Monday.
If you are getting out in the mountains, please share your observations on the Mountain Information Network!
Snowpack Summary
Light snowfall and elevated winds through Sunday night will continue to form slabs, especially in wind exposed terrain. After a steady period of elevated winds you'll now likely find large, hard wind slabs in many alpine areas. Below treeline, the interface below our latest storm snow likely presents as a crust.
The mid and lower snowpack contains multiple crusts that seem to be holding strong.
Snowpack depths are around 100 cm below treeline, but shrink rapidly below 1600 m. Alpine snowpacks are expected to be around 140 cm deep, but could be 200 cm or more in areas with more snowfall or wind-transported snow. The deepest snowpacks this season have been reported near Blue River and Valemount.
Terrain and Travel
- Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
- Avoid freshly wind loaded features, especially near ridge crests, roll-overs and in steep terrain.
- Back off if you encounter whumpfing, hollow sounds, or shooting cracks.
Problems
Wind Slabs
Steady snowfall and wind have been forming wind slabs at higher elevations for the past week. This means you'll find an increasing mix of large hard wind slabs and smaller but more reactive new slabs as you gain elevation.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Nov 29th, 2021 4:00PM
