Avalanche Forecast
Regions: Banff, Banff Yoho Kootenay, East Side 93N, Field, Kootenay, LLSA, Lake Louise, Little Yoho, Sunshine, West Side 93N.
Although we haven't seen the wind increase yet, they are still forecasted to increase to strong Friday night. This may create new windslabs and cause some loose dry avalanches.
The deep persistent problem remains the layer of greatest concern on large alpine slopes.
Confidence
Moderate
Avalanche Summary
Today, sunshine found thin windslabs in steep Northerly terrain that were reactive to explosives. Around Lake Louise, some loose dry avalanches were triggered by explosives in unworked terrain.
In the past week, we have seen several avalanches both natural and explosive triggered up to size 2 on the deep persistent layer. The common theme for these avalanches were North aspects in the alpine in steep or extreme terrain.
Snowpack Summary
10-20 cm of snow from last week lies on an early-season snowpack measuring 50-90 cm at treeline. The main layer of concern continues to be the October crust near the ground, where facets and depth hoar are developing. Overall the snowpack is losing its support/cohesion with facet development.
Weather Summary
Slightly warmer on Saturday with alpine temperatures around-10C. Westerly winds are forecast to increase to strong overnight Friday and into Saturday. Flurries are expected with the greatest amounts in the Northern part of the region (5-10 cm). See the image below for tables.
Terrain and Travel Advice
- Be aware of the possibility for full depth avalanches due to deeply buried weak layers.
- 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
No significant wind occured on Friday, but it is still forecast to increase to strong Friday night through Saturday. If this occurs, we expect some windslab development in the lees of features.
Aspects: North, North East, East, South East, North West.
Elevations: Alpine.
Likelihood: Possible
Expected Size: 1 - 1.5