Avalanche Forecast
Issued: Mar 15th, 2022 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Storm Slabs and Persistent Slabs.
ahanna,
Avalanche Canada
Storm slabs likely remain triggerable by riders at upper elevations on Wednesday. Tune into any signs of instability like cracking or recent avalanches as indicators to back off into lower angle or less wind-loaded terrain.
Summary
Confidence
Moderate - Forecast snowfall amounts are uncertain.
Weather Forecast
Convective squalls may produce localized heavy snowfall overnight. Exact amounts and locations are difficult to predict in this kind of pattern. The Coquihalla is a likely candidate.
Tuesday night: Snowfall 5-10 cm, 30-40 km/h southwest wind, alpine temperature -5 C. Freezing level 700m.
Wednesday: Flurries 1-3 cm, 20-30 km/h southwest wind, treeline temperature -5 C. Freezing level 1400 m.
Thursday: Flurries up to 5 cm, 30-40 km/h southwest wind, treeline temperature -4 C. Freezing level 1400 m.
Friday: Flurries bringing a trace, 20-30 km/h southwest wind, treeline temperature -5 C. Freezing level 1400 m.
Avalanche Summary
On Tuesday, debris from a natural size 2 storm slab was observed in a low elevation runout zone in the Coquihalla.
On Monday, natural and skier controlled size 1 storm slabs were observed in wind loaded convexities around treeline.
The last reported persistent slab activity was on Wednesday when a rider triggered a persistent slab avalanche along the Duffey at 2000 m on a northeast aspect. Another suspected persistent slab avalanche was triggered by a rider on Tuesday in the north of the region. Both slabs were around 30 to 40 cm thick, resulting in small avalanches (size 1 to 1.5). This problem appears to be spotty and isolated but remains possible for humans to trigger, where it exists.
Snowpack Summary
10-20 cm of recent snow has been redistributed into wind slabs at upper elevations. The recent snow sits over variable surfaces including a hard melt-freeze crust on solar aspects and low elevations and perhaps a thin layer of surface hoar or faceted snow in sheltered areas.
Around 30 to 60 cm deep, sugary faceted grains may be found around a melt-freeze crust that formed February in the north of the region (e.g., Duffey, Hurley). The layer has been most problematic on isolated north to northeast aspects around 1900 to 2100 m. Check out this forecaster blog for more info.
Various crusts may be found in the south of the region (e.g., Coquihalla, Manning) but reports suggest they are bonding to the snowpack and are not an avalanche concern.
There are no deeper concerns at this time.
Terrain and Travel
- Continue to make conservative terrain choices while the storm snow settles and stabilizes.
- Avoid freshly wind loaded features, especially near ridge crests, roll-overs and in steep terrain.
- Be aware of the potential for large avalanches due to the presence of buried persistent weak layers.
Problems
Storm Slabs
Fresh storm slabs may be touchy and propagate widely. The most likely place to trigger an avalanche is in wind-loaded terrain features.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Persistent Slabs
A buried crust surrounded by faceted grains produced avalanches in the north of the region last week. This layer is buried 30-60 cm deep in this area and was most problematic on north to northeast aspects around 1900 m to 2100 m.
Aspects: North, North East, East, West, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Mar 16th, 2022 4:00PM
