Avalanche Forecast
Issued: Mar 27th, 2023 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Persistent Slabs, Deep Persistent Slabs and Loose Wet.
JA,
Avalanche Canada
Large triggers such as cornice falls continue to trigger persistent slabs. Human triggering of the persistent and deep persistent slab remains possible especially in terrain with thin to thick snowpack depths.
Solar warming should once again factor into your trip planning - avoid exposure to southerly slopes and exposure to cornices during peak warming.
Elevated hazard rating below tree line reflects increasing freezing level and solar warming - take advantage of good overnight freezing by starting and finishing early.
Summary
Confidence
Moderate
Avalanche Summary
Limited new activity noted on the Icefields Parkway on Sunday - a couple of dry loose size 1.5 in the alpine Mount Cirus; serac activity estimated size 2 off of Stutfield.
Maligne patrol noted a cornice triggered persistent slab size 2.5 east aspect and a size 2 persistent slab west aspect both visible just south of Medicine lake.
Cornice failures and loose wet avalanches may increase late afternoons with forecasted clear skies and rising daytime freezing level.
Don't forget to post avalanche observations to the MIN.
Snowpack Summary
2-10cm of new snow from early Sunday sits over a breakable sun crust at all elevations on solar aspects. Approximately 20-50cm down is a persistent slab sitting over a facet layer in sheltered terrain or a weak crust at low elevations / southerly slopes. The lower snowpack is generally weak with large facets and depth hoar at the base.Snow depth varies from 60-170cm.
Weather Summary
Surface ridge of high pressure will provide for clear skies on Tuesday. Freezing level will rise to 1600m with light northerly winds. Mostly clear conditions will continue on Wednesday. An approaching low from the north will bring increasing cloud late Wednesday with the potential for isolated flurries. Freezing level will reach 2100m. Mix of sun and cloud on Thursday with continued diurnal temperature pattern.
Terrain and Travel Advice
- Avoid shallow, rocky areas where the snowpack transitions from thick to thin.
- Cornices become weak with daytime heating or solar exposure.
Problems
Persistent Slabs
There is a cornucopia of weak interfaces throughout the snowpack depending on aspect, elevation, and local terrain influences. There have been a few avalanches last week which appeared to have stepped down to multiple layers.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Deep Persistent Slabs
The bottom of the snow pack is inherently weak with well developed Facets and Depth Hoar. Persistent slab avalanches can step down to the deep persistent slab meaning large triggers can influence this basal weakness.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Loose Wet
Strong solar warming and rising freezing level will likely break down a weak solar crust mid to late afternoon. Wet loose avalanches will likely initiate from steep rocky terrain on southerly aspects.
Aspects: South East, South, South West, West.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Mar 28th, 2023 4:00PM
