Avalanche Forecast
Issued: Mar 13th, 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
Watch for fresh storm slabs building throughout the day. Be aware of the potential for large avalanches due to the presence of a buried weak layer.
Summary
Confidence
Moderate - We are confident the likelihood of avalanche will increase with the arrival of the forecast weather.
Weather Forecast
Sunday night: Snowfall 5-15 cm, 40-60 km/h southwest wind, alpine temperature -5 C. Freezing level 1200 m.
Monday: Snowfall, accumulation 10-20 cm, 40-60 km/h southwest wind, alpine temperature -4 C. Freezing level 1400 m.
Tuesday: Snowfall 15-25 cm, 30-50 km/h southwest wind, alpine temperature -5 C. Freezing level 1300 m.
Wednesday: Overnight snowfall 5-15 cm then cloudy, 10-20 km/h southwest wind, treeline temperature -7 C. Freezing level 1300 m.
Avalanche Summary
On Saturday, a few skier controlled size 1 loose dry and soft wind slab avalanches were reported.
Persistent slab activity has dwindled since last week. The most recent activity was on Tuesday when two avalanches were triggered by riders on northeast aspects at treeline and alpine elevations, similar to the trend of previous avalanches. It remains possible that humans could trigger this layer, where it exists.
Snowpack Summary
New snow and southwest wind have likely formed wind slabs in lee terrain features. The snow accumulates over a thin layer of variably wind affected, faceted snow or surface hoar that overlies a hard melt-freeze crust found on all aspects below around 1500 m and on sun-exposed slopes into the alpine.
Around 40 to 80 cm deep, a weak layer of sugary faceted grains may be found above a melt-freeze crust that formed in February. This layer has been most prevalent on north to northeast aspects between 1600 m and 2100 m. Check out this forecaster blog for more info. The current storm will provide us with feedback on the reactivity of this layer.
There are no deeper concerns at this time.
Terrain and Travel
- Storm snow and wind is forming touchy slabs. Use caution in lee areas in the alpine and treeline.
- Storm slab size and sensitivity to triggering will likely increase through the day.
- Avoid areas with overhead hazard.
- Storm slabs in motion may step down to deeper layers resulting in large avalanches.
Problems
Storm Slabs
Fresh storm slabs will likely be reactive as the new snow is not expected to bond well to the old surface. They are most likely to be triggered in deeper deposits of freshly wind loaded snow.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Persistent Slabs
A weak layer of faceted grains above a hard melt-freeze crust may be found around 40 to 80 cm deep. Last week this layer produced large avalanches. The problem is most prevalent on north to northeast aspects between 1600 m and 2100 m.
Aspects: North, North East, East, West, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Mar 14th, 2022 4:00PM
