Avalanche Forecast
Issued: Nov 30th, 2020 5:06PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs and Deep Persistent Slabs.
Conrad Janzen,
As we enter a week of high pressure and good travel, use caution in steep larger terrain features. Things are pretty good overall but a few recent large avalanches show the potential for failures on wind slabs or the basal weakness in some locations.
Summary
Weather Forecast
Tuesday the clouds clear out as a high pressure system moves into the Rockies with decreasing winds shifting from the W to the NW. On Wednesday an inversion is forecast with very warm alpine temperatures in the middle of the day. The rest of the week also looks calm, clear and mild.
Snowpack Summary
Variable surface conditions exist with hard wind slabs in exposed locations and softer snow in more sheltered areas. The Nov 5 facet/crust combo is down 50-80 cm and producing variable test results, but often 'sudden' in character. This crust extends up to 2500 m on N aspects and higher on solar aspects. Snow depths at treeline are 70-130 cm.
Avalanche Summary
Minimal avalanche activity observed Monday at local ski hills and on a ski tour in the Sunshine area. There have been a few isolated larger avalanches in the last week on deeper layers including a size 2.5 avalanche on the W aspect of Dolomite Peak on Sunday in a cross loaded gully feature and a couple deep avalanches on steep glacier features.
Confidence
Due to the number and quality of field observations
Problems
Wind Slabs
Wind slabs exist in exposed alpine areas from strong winds over the past week. Give these time to bond and be cautious if you are in steep lee loaded or cross loaded terrain.
- Be careful with wind loaded pockets, especially near ridge crests and roll-overs.
- If triggered the wind slabs may step down to deeper layers resulting in large avalanches.
Aspects: North, North East, East, South East, South, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Deep Persistent Slabs
The Nov 5 crust has facets growing above and below it, and exists up to 2500m on shady aspects and higher on solar aspects. We have seen a few isolated avalanches on this layer so use caution in large steep terrain features.
- Pay attention to overhead hazards like cornices which could trigger the deep persistent slab.
- Be aware of thin areas that may propogate to deeper instabilites.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Dec 1st, 2020 4:00PM
