Avalanche Forecast
Issued: Feb 15th, 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.
Tim Haggarty,
Parks Canada
Continued inputs of snow and wind over the last few days have built wind slabs and further developed cornices. With these elements around the potential for avalanches on the deep persistent layer is elevated.
Summary
Weather Forecast
The west winds will diminish Sunday to moderate values in the alpine and should stay in that range over the next few days. Light flurries will also continue with alpine temps trending a bit down to -20 values until some expected warming and clearing on Tuesday.
Snowpack Summary
Up to 35cm over the last few days sits over top of a well settled upper and mid-pack. The lower snowpack (bottom 50cm) consists of weaker facets and depth hoar which are well preserved in areas under 150cm HS. These are still producing moderate shears with snowpack tests. Isolated wind slabs exist near ridge tops and lee terrain in the alpine.
Avalanche Summary
The ski-hills worked with a fresh round of wind slabs again today (the same for almost a week straight): small soft slabs up to 40 deep with a few natural cornice falls triggering small slabs. Sunshine Village staff triggered a sz 3, to ground, on the south side of Lookout Mountain: "The Megaldon", with explosives.
Confidence
Problems
Wind Slabs
Wind effect and slab development should be anticipated as you leave the trees. Wind effect is extensive in the alpine and hard slabs should be expected.
- Caution on open steep slopes at treeline and above that have been exposed to wind loading.
- If triggered the wind slabs may step down to deeper layers resulting in large avalanches.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Deep Persistent Slabs
Several larger avalanches failing on the basal facet/depth hoar have been observed in the past week. This problem is more susceptible to triggering in areas with a thin snowpack (~150cm) where they are well preserved and are hard to predict.
- 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 16th, 2020 4:00PM
