Avalanche Forecast
Issued: Nov 27th, 2020 4:38PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs and Deep Persistent Slabs.
Lisa Paulson,
Summary
Weather Forecast
Up to 10-15 cm expected along the Divide, with the highest amounts expected on the West side in higher terrain. Strong winds should ease early Saturday and through the day. Temperatures will also fall slightly on Saturday. Sunday looks cooler, mix of sun and clouds with winds picking up through the day.
Snowpack Summary
Alpine terrain scrubbed by recent strong W-SW wind created windslabs at treeline and above. The Nov 5 facet/crust combo is down 50-80 cm and producing variable test results from easy to hard, but 'sudden' in fracture character. The Nov crust extends up to 2500 m on N aspects and higher on solar aspects. Snow depths at treeline are 70-130 cm.
Avalanche Summary
New touchy cornice growth in the last 24 hrs. Sunshine forecasters report stubborn windslabs at treeline 10-15 cm think. Lake Louise area saw less reactivity. One recent size 2.5 avalanche observed on a steep moraine lee feature at 2100 m, in the path next to the Takakkaw Falls hostel. The crown was 60-70 cm deep and propageted about 80 m.
Confidence
Due to the number of field observations
Problems
Wind Slabs
Continued strong Westerly winds have created windslabs in the alpine and at treeline. Less reactive today at treeline in some locations.
- If triggered the wind slabs may step down to deeper layers resulting in large avalanches.
- Be careful with wind loaded pockets, especially near ridge crests and roll-overs.
Aspects: North, North East, East, South East, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Deep Persistent Slabs
The deeper Nov.5 crust has facets growing above and below it, and exists up to 2500m on shady aspects and higher on solar aspects. New load from recent winds may make this layer more sensitive
- Be aware of thin areas that may propogate to deeper instabilites.
- Pay attention to overhead hazards like cornices which could trigger the deep persistent slab.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Nov 28th, 2020 4:00PM
