Avalanche Forecast
Regions: Banff, Banff Yoho Kootenay, East Side 93N, Field, Kootenay, LLSA, Lake Louise, Little Yoho, Sunshine, West Side 93N.
Mt. Hector, Noseeum, Silverhorn/Observation, and Bison avalanche closure zones on Highway 93N are CLOSED on Wednesday, February 15th for avalanche control.
Confidence
Moderate
Avalanche Summary
No new reports of natural or skier triggered avalanches on Tuesday. Lake Louise snow safety triggered a few thin windslabs to size 1.5 with explosives.
Over the past week there have been numerous natural, skier and explosive triggered avalanches to size 3, some with wide propagations an many stepping to ground.
On Monday, skiers triggered a size 2 windslab on the convex roll in Wawa bowl near Sunshine Ski area. Near Lake Louise ski area, in out of bounds bowl skiers triggered a size 2 windslab on a reload of a bed surface of basal facets from large avalanche on Dec 30. Avalanche control on Mt. Dennis and Mt. Field on Monday produced results up to size 3.
Over last weekend there were several notable avalanches. On Saturday, there was a MIN report of a remote-triggered slide with wide propagation in the Sunshine backcountry. On Sunday, a visitor safety team also triggered a healthy size 2.5 (80 wide) at 2400m on observation glades and another party on Helen Shoulder triggered a size 2.
Snowpack Summary
A mix of hard and soft slabs up to 50 cm deep lie on the surface due to last week's storm snow and extreme westerly wind. Non-wind affected areas have approximately 20 cm of soft snow on the surface.
The surface slabs sit on top of 30-60 cm over top of the January crust/facet interfaces and or firmer midpack layer from previous wind effect. The lower snowpack remains very weak and faceted.
Weather Summary
A ridge builds in the region, bringing clearer skies for Wednesday and Thursday. Light to moderate NW winds on Wednesday shift Thursday to moderate to strong Westerly winds as the ridge breaks down. Friday, expect light flurries (2-5 cm) with moderate to strong westerly wind. Alpine temperatures will range from -5 to -12C.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Make conservative terrain choices and avoid overhead hazard.
- Be careful with wind slabs, especially in steep, unsupported and/or convex terrain features.
- If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.
Avalanche Problems
Wind Slabs
Soft and hard slabs up to 50 cm thick exist throughout the region. Humans can trigger these. In many areas, the older wind slabs remain reactive as they overlay various surfaces like crusts or a layer of facets on a firmer mid-pack from the previous wind effect. There have been many reports over the past few days of windslab avalanches.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood: Likely
Expected Size: 1 - 2.5
Deep Persistent Slabs
There have been numerous natural and human-triggered avalanches on the basal facets and depth hoar recently. They are either initiating on this layer or more frequently initiating as a wind slab which steps down.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood: Possible - Likely
Expected Size: 1.5 - 3.5