Avalanche Forecast
Regions: Banff, Banff Yoho Kootenay, East Side 93N, Field, Kootenay, LLSA, Lake Louise, Little Yoho, Sunshine, West Side 93N.
The winds have increased and are forecasted to get stronger, we are a little uncertain as to the extent and reactivity of the fresh windslabs. We also may see some loose dry activity with the increased wind in extreme terrain.
The Oct crust deep persistent problem remains the layer of greatest concern on large alpine slopes.
Confidence
Moderate
Avalanche Summary
No new avalanches were observed or reported today. In the Sunshine region, a natural size 2 avalanche on the deep persistent layer was observed on Thursday on an alpine North aspect in extreme terrain and two days prior on Scarab Peak. Over the past few days, there have been reports of deep slab avalanches with explosives at both Sunshine and Lake Louise ski hills.
Snowpack Summary
10-20 cm of snow from last week lies on an early-season snowpack measuring 50-90 cm at treeline. Two weak layers are present: the November 9 crust, found 25-40 cm above the ground, and an October crust near the ground, where facets and depth hoar are developing. Observations of the October layer are limited, but it appears most prominent on northerly aspects at treeline and above.
Weather Summary
Low of -13C and highs of -7C Friday. Westerly winds increase to strong by mid-day Friday and continue into Saturday with very light flurries. See image below for tables.
Terrain and Travel Advice
- Be aware of the possibility for full depth avalanches due to deeply buried weak layers.
- Wind slabs are most reactive during their formation.
- Avoid freshly wind-loaded terrain features.
Avalanche Problems
Deep Persistent Slabs
The crust/facet layer from October 23, located just above the ground, is capped by a 50-80 cm slab. This layer has caused avalanches over the past week. The extent of the problem remains uncertain, but we advise exercising extra caution on steep, open alpine features.
Aspects: North, North East, East, West, North West.
Elevations: Alpine, Treeline.
Likelihood: Possible
Expected Size: 1.5 - 2.5
Wind Slabs
We expect new windslab development in the lees of terrain features. Since the snowfall last week, the winds have been light. Tuesday night the westerly winds increased to moderate and are forecasted to increase to strong Friday through Saturday.
Aspects: North, North East, East, South East, South, North West.
Elevations: Alpine.
Likelihood: Likely
Expected Size: 1 - 2