Avalanche Forecast
Issued: Feb 19th, 2020 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.
Stephen Holeczi,
Parks Canada
Watch for local wind loading Thursday especially in gully features and near ridge crests. Shallow (under 150cm) snowpack areas have very prominent basal facets and depth hoar. Terrain choice is the best defense against this problem.
Summary
Weather Forecast
A temperature inversion (warmer in the alpine, colder in the valley) will start to break down Thursday bringing with it increased winds which will be in the strong range (up to 80kmh) in the alpine. Temperatures will be in the -10C range but likely colder in the Louise region in the AM. No snow is forecast in the next 24 hours.
Snowpack Summary
Continued settlement and cool temperatures are slowly stabilizing the recently formed windslabs, which could still be triggered in steep, loaded areas in the alpine. Some sun crust formation on steep S and SW facing terrain. Weak, facetted snow near the base of the snowpack persists in much of the range, producing isolated but large avalanches.
Avalanche Summary
No new avalanches today. There was a report yesterday of a size 2.5 wind slab that was triggered by ski tourers on the scramblers route of Cascade Mountain. It was on a steep SW slope in the alpine with no involvement.
Confidence
Problems
Wind Slabs
Increased winds Thursday may add to recently formed wind slabs that can still be triggered by people in steep leeward areas in the alpine. Cornices have grown very large in recent weeks, so watch your exposure to them carefully.
- If triggered the wind slabs may step down to deeper layers resulting in large avalanches.
Aspects: All aspects.
Elevations: Alpine.
Likelihood
Expected Size
Deep Persistent Slabs
Several large avalanches failing naturally on the basal facet/depth hoar have been observed in the past week. These are hard to predict, but are most likely in areas with a thin snowpack (~150cm) where the basal facets and depth hoar are prominent.
- Pay attention to overhead hazards like cornices which could easily trigger the deep persistent slab.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Feb 20th, 2020 4:00PM
