Avalanche Forecast
Regions: Banff, Banff Yoho Kootenay, East Side 93N, Field, Kootenay, LLSA, Lake Louise, Little Yoho, Sunshine, West Side 93N.
Some new snow and incoming wind will build fresh wind slabs on Tuesday. Following this, clear weather on Wednesday will activate said storm snow due to solar radiation and daytime warming.
Confidence
High
Avalanche Summary
Sunshine patrol reported ski cutting some small size 1 wind slabs in immediate alpine lee areas. Otherwise, no new avalanches were observed or reported on Monday.
It has been a week since the last skier triggered avalanches on the Feb 3rd persistent weak layer occured. These involved a skier remote in Purple Bowl and a skier accidental at the Cathedral Glades.
Snowpack Summary
New surface crusts on all solar aspects and up to 2500 m on north aspects are buried by a skiff of snow. On high north aspects 15-20 cm of recent storm snow remains dry with some wind effect near ridgecrests.
The February 3 persistent weak layer remains a concern for human triggering in shallow snowpack areas on northerly alpine aspects where no crusts are found in the upper snowpack and the midpack remains thin and weak.
Weather Summary
5-10cm of snow is expected on Tuesday. It will be accompanied by cool-ish temperatures of close to 0 in the valley and -10 at the ridge level. There is a good chance the wind will blow strong from the West, but at minimum, it will be moderate.
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Terrain and Travel Advice
- Remember that in the spring strong solar radiation and warm temperatures can weaken the snow in a matter of minutes.
- Watch for wind-loaded pockets especially around ridgecrest and in extreme terrain.
- Avoid thin areas like rock outcroppings where you're most likely to trigger avalanches failing on deep weak layers.
Avalanche Problems
Wind Slabs
Up to10cm of new snow with moderate to strong West wind by Tuesday end of day, will likely build new wind slabs in alpine lee areas. Track this at the local level as snow fall amounts and wind velocity can be variable.
Aspects: North, North East, East, North West.
Elevations: Alpine.
Likelihood: Possible
Expected Size: 1 - 2
Persistent Slabs
The Feb 3 layer is down 60-120 cm. In shallow snowpack areas on northerly alpine aspects, this layer may still be sensitive to skiers, with remote triggering observed in a couple of instances last week. All recent avalanches that initiated on this Feb 3 layer stepped down to the basal facets/ground.
Aspects: North, North East, North West.
Elevations: Alpine.
Likelihood: Unlikely - Possible
Expected Size: 2 - 3