Avalanche Forecast
Issued: Feb 11th, 2020 5:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs and Deep Persistent Slabs.
MBender,
Avalanche Canada
Little precipitation along with recent winds blowing from a variety of directions will keep wind slabs at upper elevations the main concern.
Summary
Confidence
Weather Forecast
Tuesday Night: Cloudy with isolated flurries. Moderate northwest wind. Alpine high temperatures around -8.
Wednesday: Cloudy with sunny breaks. Light west wind. Alpine high temperatures around -5. Freezing level 1000 m
Thursday: Scattered flurries, accumulation 5 cm. Light to moderate southwest wind. Alpine high temperatures around -7. Freezing level 900 m
Friday: Mainly cloudy with isolated flurries. Moderate west wind. Alpine high temperatures around -6. Freezing level 1000 m
Avalanche Summary
On Monday there were reports from the central part of the region of two explosives triggered deep persistent avalanches size 2.5 and 3 running on north aspects in the alpine. One of these ran on facets sitting glacial ice.
Sunday and Monday's reports also showed a few windslab avalanches running to size 1.5 in alpine terrain from a variety of aspects.
On Saturday there was a report of remotely triggered (from a distance) wind slab avalanche size 2.5 avalanche at 2350 m on a southeast aspect in the north of the region. The details can be seen in this MIN post. There were also reports of numerous loose dry avalanches running in steep terrain size 1-1.5.
Snowpack Summary
20-40 cm of snow accumulating through the last week sits over older wind-affected snow at high elevations, or over a widespread melt-freeze or rain crust with a variable upper extent of 1800-2000 metres in elevation. The recent snow has mainly shown reactivity where winds have had a chance to redistribute it into new slabs.
A weak layer of surface hoar may still be found about 90 cm deep around Golden and Kimberley, 50 cm deep around Invermere, and 130 cm deep along Kootenay Lake. Recent reports from the Golden area suggest a positive stabilizing trend. At lower elevations this layer has likely been bridged over by the above-mentioned crust.
The base of the snowpack contains basal facets. It remains possible to trigger these deep weak layers in shallow rocky start zones or from a heavy trigger such as a cornice fall.
Terrain and Travel
- Be careful as you transition into wind affected terrain.
- Use extra caution around cornices: they are large, fragile, and can trigger slabs on slopes below.
- Avoid shallow, rocky areas where the snowpack transitions from thick to thin.
Problems
Wind Slabs
Recent light snowfall combined with elevated and shifting winds have built wind slabs on a variety of aspects.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Deep Persistent Slabs
A layer of weak, sugary facets persists at the bottom of the snowpack at higher elevations. Steep, rocky alpine features where the snowpack transitions from thick to thin are the likely trigger points for this deep persistent slab problem. Easier-to-trigger wind slab avalanches or cornice falls could step down to this layer, resulting in very large and destructive avalanches.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Feb 12th, 2020 5:00PM
