Avalanche Forecast
Regions: Brazeau, Churchill, Cirrus-Wilson, Fryatt, Icefields, Jasper, Maligne, Marmot, Miette Lake, Pyramid.
A long run of strong to extreme southwesterly wind continues into Monday, but change is under way. Wind slab and deep persistent slab natural activity is still possible. When assessing your ski objectives, look for overhead hazards such as large alpine bowls, cornices, or cross loaded slopes. Choose terrain conservatively and bear in mind the potential for a low probability high consequence avalanche occurrence.
Confidence
Moderate
Avalanche Summary
Parkway patrol noticed few large natural deep persistent slab avalanches in the alpine, we suspect these avalanches happened in the last 24- 48 hours and ran on basal facets. Intense wind transport in the alpine and tree line observed around the Icefields area.
Don't forget to post avalanche observations to the MIN.
Snowpack Summary
Recent strong to extreme southwesterly winds stripping exposed features and building wind slabs in the alpine and at tree line. In sheltered locations 30cm of low density snow lies over a generally weak mid and bottom snowpack with facets and depth hoar at the base. The height of snow is variable from 50 to 150cm.
Weather Summary
On Monday, winds will subside and precipitation will start in the afternoon. Up to 15 cm of snow forecast by Tuesday morning.On Tuesday, winds switch to light to moderate out of northeast, precipitation peters off by the morning and alpine temperatures will plummet to -25 C.
Detailed weather forecasts from Avalanche Canada: https://avalanche.ca/weather/forecast
Terrain and Travel Advice
- Expect slab conditions to change drastically as you move into wind exposed terrain.
- Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
Avalanche Problems
Wind Slabs
With the new snow and persistent moderate to strong southwesterly winds in the forecast, new wind slabs will be forming in the lee slopes. These wind slabs will have a potential to overload the deep persistent layer below and result in larger than expected avalanches.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood: Likely
Expected Size: 1 - 2.5
Deep Persistent Slabs
The bottom of the snow pack is inherently weak with well developed Facets and Depth Hoar. Large natural and explosive triggered avalanches in the last week have run on this layer.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood: Possible
Expected Size: 1.5 - 3