Avalanche Forecast
Issued: Apr 21st, 2022 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs and Cornices.
TRettie,
Avalanche Canada
Carefully assess new snow amounts. The size and likelihood of wind slab avalanches will be greatest in localized areas that receive more than 15 cm of new snow.
Summary
Confidence
Moderate - Uncertainty is due to the timing, track, & intensity of the incoming weather system.
Weather Forecast
Thursday night: Up to 20 cm of new snow possible for the southern part of the region, trace amounts expected for the north. Light westerly winds and a low of -4 at 2000 m.
Friday: A mix of sun and cloud with flurries bringing up to 5 cm of new snow with light northwest winds. Freezing level around 2000 m.
Saturday: A mix of sun and cloud with no new snow expected. Light variable winds and freezing levels rising to 2200 m.
Sunday: Sunny with no new snow expected. Light to moderate south winds and freezing levels rising to 2300 m.
Avalanche Summary
On Wednesday several skier triggered storm slab avalanches to size two were observed in the region. These avalanches were generally at upper treeline or alpine. Small wet loose avalanches were also observed on solar aspects.
We suspect that wind slab will remain reactive to rider traffic at treeline and above.
Snowpack Summary
On northerly aspects above 2000 m, 15 to 30 cm of new snow overlies a variety of surfaces including old wind effect and facets. The upper snowpack contains several crusts that extend to mountain tops on solar aspects.
Cornices are very large and exposure to slopes beneath them should be minimized, especially if the weather is sunny, warm, or windy. The snowpack deteriorates rapidly at lower elevations.
Terrain and Travel
- Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
- Closely monitor how the new snow is bonding to the crust.
- Pay attention to cornices and give them a wide berth when traveling on or below ridges.
Problems
Wind Slabs
New wind slabs will likely be found in exposed treeline and alpine terrain. These new slabs likely won't bond well to the underlying surfaces.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Cornices
Cornices may be weak and reactive to human triggers. Give them a wide berth when travelling on ridges. They are a significant hazard alone and may produce large slab avalanches as they fall onto the slope below. Cornice falls are more likely when the weather is sunny, warm, or windy.
Aspects: North, North East, East, South East, North West.
Elevations: Alpine.
Likelihood
Expected Size
Valid until: Apr 22nd, 2022 4:00PM
