Avalanche Forecast
Regions: Banff, Banff Yoho Kootenay, East Side 93N, Field, Kootenay, LLSA, Lake Louise, Sunshine, West Side 93N.
Human triggering of avalanches remain very likely.
We are in a dangerous time for decision-making: the danger is less obvious, people want to ski, and the weather is nice. Manage your desires carefully.
Confidence
Moderate
Avalanche Summary
LL ski hill observed a natural size 2.5 slab avalanche out of S aspect and rocky start zone, on Wednesday. Avalanche control in the Field area produced avalanches up to size 3 on Mt Cathedral.
A group digging a snowpit in low angle terrain with no overhead exposure on Observation Peak on March 18th felt a whumph that remote triggered 5-6 avalanches up to size 2.5.
Evidence of a widespread natural cycle in the last 96 hours was observed throughout the region today during a flight.
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. This condition will be slow to stabilize.
Expect a surface crust on solar aspects treeline and below.
Weather Summary
Wednesday night: Cloudy with clear periods and isolated flurries. Alpine temperature: Low -9 °C. Ridge wind southwest: 15-35 km/h
Thursday: A mix of sun and cloud with isolated flurries. Alpine temperature: High -5 °C. Ridge wind west: 20 km/h gusting to 45 km/h
Friday: Mainly cloudy with scattered flurries. Accumulation: 5 cm. Alpine temps: Low -10 °C, High -5 °C. Ridge wind southwest: 15 km/h gusting to 50 km/h
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 overlies mid-pack facets and depth hoar at the ground. Numerous avalanches have been failing on both these layers (persistent AND deep persistent slabs) and this will not change anytime soon as these problems are slow to heal. Avoid starting zones and be very wary of overhead hazard.
Aspects: All aspects.
Elevations: All elevations.
Likelihood: Possible - Likely
Expected Size: 2 - 3.5
Loose Wet
If the sun is out, the snow will warm quickly and loose wet avalanches will start to run. These could be a trigger for the deeper layers resulting in much larger avalanches.
Aspects: South, South West, West.
Elevations: All elevations.
Likelihood: Unlikely - Possible
Expected Size: 1 - 2