Avalanche Forecast
Regions: Banff, Banff Yoho Kootenay, East Side 93N, Field, Kootenay, LLSA, Lake Louise, Sunshine, West Side 93N.
Time to refresh on the Spring Conditions hazard rating. For Wed - Thurs, expect a daily melt-freeze cycle. Hazard ratings reflect the highest danger for the day.
Powder exists on high north aspects. The persistent problem is a concern for terrain selection on north aspects & south aspects when crusts melt.
Start & finish early!
Confidence
Moderate
Avalanche Summary
On Monday, a skier crossing the slope triggered a size 1 slab that failed on the persistent basal facets just below Peyto Lake viewpoint. Sunshine patrol also a slab avalanche, likely triggered by a loose wet avalanche, that scrubbed to ground resulting in a size 2.5 avalanche on an alpine SSE aspect.
Tuesday, HWY 93 road patrol, one size 2 recent cornice failure on Crowfoot mountain scrubbing to ground in extreme terrain.
Snowpack Summary
Light wind effect in the alpine. On alpine north aspects, 15-30 cm of dry settled snow sits over the Mar 27 crust that exists to ~2500 m. On solar aspects sun crusts are present to ridgetop with moist snow later in the day. A supportive surface crust exists in most places below treeline.
A 30-70 cm firm midpack overlies the weak January facets and basal depth hoar which remain a concern.
Treeline snowpack depths range from 100 to 150 cm.
Weather Summary
Wednesday - A mix of sun and cloud with scattered flurries and moderate SW wind. There is some variation in the predicted cloud cover and temperatures between the weather models and across the region. Wednesday night, we may see a reasonable freeze with clearing skies and treeline temperatures dipping below -10°C
Thursday - mostly sunny
See the weather table for more details
Terrain and Travel Advice
- Avoid steep, sun-exposed slopes when the air temperature is warm or when solar radiation is strong.
- Start your day early and be out of avalanche terrain during the heat of the day.
Avalanche Problems
Persistent Slabs
Below the recent snow a 30-80 cm slab sits on the weak facetted lower snowpack. On all but high north aspects, recent sun crusts and the March 27 rain crust cap this slab providing some security. Use caution in higher, thin snowpack areas or where these crusts are weak or breaking down with heating.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood: Possible
Expected Size: 2 - 3
Wind Slabs
5-10 cm from Tuesday night with WSW wind has formed thin windslabs on alpine lee features reactive to ski cuts by ski hill snow safety teams.
Aspects: North, North East, East, South East, North West.
Elevations: Alpine.
Likelihood: Possible
Expected Size: 1 - 2
Loose Wet
The degree of cloud cover varies between weather models for Wednesday. This problem will emerge IF surface crusts break down with prolonged solar radiation.
Aspects: South East, South, South West, West.
Elevations: All elevations.
Likelihood: Possible
Expected Size: 1 - 2