Avalanche Forecast
Issued: Mar 1st, 2023 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs and Persistent Slabs.
ahanna,
Avalanche Canada
6am update: The wind has arrived. And there is a ton of new snow for it to blow around. Deep, fresh wind slabs will be reactive today. The new load will stress deep instabilities that have potential to produce very large avalanches.
Summary
Confidence
Avalanche Summary
Wind slabs have been reactive lately and are expected to continue. Natural wind slab avalanches up to size 2 and wind-triggered loose dry up to size 1.5 were reported in the White Pass area on Tuesday. On Monday, a size 1.5 skier-triggered wind slab was reported in this MIN from Fraser. We really appreciate you for sharing!
Our field team recently observed a large natural wind slab avalanche that stepped down to a deeper weak layer in the Paddy Peak area, likely during the outflow winds on the weekend.
Snowpack Summary
30-40 cm of recent low density storm snow sits over firm, old, wind-hammered surfaces. If the wind picks up on Thursday, all this fresh snow is available to blow around and wind slabs are likely to form in lee terrain features.
In the mid snowpack, a couple of buried crusts have been associated with overlying surface hoar on north to east aspects as high as 1700 m, buried around 50 and 90 cm deep. Recent large avalanches are suspected to have run on the deeper of the two layers.
Weather Summary
Wednesday night
5-10 cm of new snow. Moderate southwest wind. Alpine low -12 ºC.
Thursday
Cloudy with isolated flurries. Moderate southwest wind. Alpine high -10 ºC.
Friday
A mix of sun and cloud with isolated flurries. Light variable wind. Alpine high -15 ºC.
Saturday
A mix of sun. Light to moderate easterly wind. Alpine high -18 ºC.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Avoid the alpine during periods of heavy loading from new snow wind and/or rain.
- Avoid freshly wind loaded terrain features.
- Wind slabs are most reactive during their formation.
- Seek out sheltered terrain where new snow hasn't been wind-affected.
- Be mindful that deep instabilities are still present and have produced recent large avalanches.
- If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.
Problems
Wind Slabs
Deep deposits of snow are being wind loaded into leeward terrain features. These wind slabs will be particularly touchy as they form.
Aspects: North, North East, East, South East, South, West, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Persistent Slabs
A weak layer of surface hoar and/or facets buried ~100 cm deep has produced occasional large, widely propagating avalanches on north to east aspects above 1500 m. Some have been remotely triggered from hundreds of meters away! A layer at this depth may not show obvious signs of instability. Best to avoid steep or unsupported high consequence alpine terrain.
Aspects: North, North East, East, North West.
Elevations: Alpine.
Likelihood
Expected Size
Valid until: Mar 2nd, 2023 4:00PM
