Avalanche Forecast
Regions: Banff, Banff Yoho Kootenay, East Side 93N, Field, Kootenay, LLSA, Lake Louise, Sunshine, West Side 93N.
Human-triggered avalanches remain likely.
Decision-making can become more challenging as the signs of danger become less obvious. Manage your desires carefully.
Confidence
High
Avalanche Summary
Over the past two weeks, many avalanches up to size 3.5 have occurred, including human-triggered, remote-triggered, and natural slides, mostly on persistent layers, often reaching the ground.
On March 18th, a group digging a snowpit in low-angle terrain on Observation Peak felt a whump, triggering 5-6 remote avalanches up to size 2.5.
The photos below show the Observation avalanche and a Bow Summit slide, highlighting deep slab potential below treeline.
Snowpack Summary
Over the past 10 days, 40-90 cm of snow has accumulated and settled into a slab, with the deepest amounts found in the Bow Summit area and along the Wapta. This sits on a very weak, faceted mid and lower snowpack and fails easily in snowpack tests also see Friday's Bow Summit fracture line profile attached below. This condition will be slow to stabilize.
Expect a surface crust on solar aspects treeline and below.
Weather Summary
Saturday - Trace amounts of snow, light to moderate winds.
Sunday - mainly cloudy, moderate West wind
see the table below
Terrain and Travel Advice
- Make conservative terrain choices and avoid overhead hazard.
- Remote triggering is a big concern, be aware of the potential for wide propagations and large, destructive avalanches at all elevations.
- Wind slabs are isolated, but may remain reactive.
Avalanche Problems
Persistent Slabs
A 40–90 cm slab sits atop mid-pack facets and depth hoar at the ground. Many avalanches have failed on both layers with wide propagations (persistent and deep persistent slabs). These problems will persist as they are slow to heal.
Aspects: All aspects.
Elevations: All elevations.
Likelihood: Likely
Expected Size: 2 - 3.5
Wind Slabs
Smaller slabs in the alpine have formed, especially near ridge top. If initiated, these may be enough to activate deeper layers. Light snow and increased winds on Friday will add to this.
Aspects: North, North East, East, South East, North West.
Elevations: Alpine.
Likelihood: Possible
Expected Size: 1 - 1.5