Avalanche Forecast
Issued: Mar 7th, 2023 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs and Deep Persistent Slabs.
JA,
Avalanche Canada
Although natural avalanche activity has slowed down, human triggering of variable wind slab and of our deep persistent problem remains possible.Thin to thick areas are the most likely trigger points.
Solar radiation should also be considered this week - especially mid day through mid afternoon on steep southerly aspects, and in terrain exposed to cornices.
Summary
Confidence
Moderate
Avalanche Summary
No significant avalanches observed on a patrol of Hwy 93 Monday.
A number of large avalanches up to size 3 were observed last week. Natural activity has tapered off but the snowpack has proven sensitive to small inputs of new snow, loading, temperature change, and potentially solar effect. The majority of last week's large avalanches initiated in the alpine but have the potential to run through all elevation bands.
Don't forget to post avalanche observations to the MIN.
Snowpack Summary
In sheltered areas the top 20 to 40cm is comprised of low density facetted crystals. There is extensive wind effect at tree line and above from previous SW winds.
This is sitting on top of a generally weak mid and lower snowpack. Facets and depth hoar linger at the base of the snowpack with the height of snow varying from 60 to 160cm.
Weather Summary
The surface ridge of high pressure will remain in place until Friday. Clear skies, variable light wind, and temperatures slightly below seasonal are expected. Freezing level forecast to remain at or near valley bottom. An upper low may bring some flurries Friday and Saturday.
Detailed weather forecasts from Avalanche Canada: https://www.avalanche.ca/weather/forecast
Terrain and Travel Advice
- If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.
- Avoid shallow, rocky areas where the snowpack transitions from thick to thin.
Problems
Wind Slabs
Previous moderate to strong winds from the SW have formed wind slabs in open tree line and in the alpine.While assessing recent wind affect, keep in mind the potential of triggering either older wind slabs below or deep instabilities at the bottom of the snowpack, especially in thin to thick zones.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Deep Persistent Slabs
The bottom of the snow pack is inherently weak with well developed Facets and Depth Hoar. Although natural avalanche activity has slowed down and snowpack test results are less conclusive on this layer; skier triggering is still possible.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Mar 8th, 2023 4:00PM
