Avalanche Forecast
Regions: Brazeau, Churchill, Cirrus-Wilson, Fryatt, Icefields, Jasper, Maligne, Marmot, Miette Lake, Pyramid.
10-20mm of precipitation with strong SW wind and warm temperatures will rapidly increase the avalanche hazard overnight on Sunday.
The Icefields Parkway will be closed from 15:00-20:00h for avalanche control on Sunday. Check AB 511 for road status updates and be sure to confirm the Icefields Parkways is open before planning any travel Sunday PM- Monday.
Maligne Lake Rd will remain closed Sunday night. Check AB511 for an update Monday AM.
Confidence
Moderate
Avalanche Summary
A natural avalanche cycle is expected overnight on Sunday. This bulletin was written at 1300h to allow for avalanche control operations Sunday afternoon. No road patrol yet today.
Don't forget to post avalanche observations to the MIN.
Snowpack Summary
Rapid loading on Sunday night will create a 15-30cm thick storm slab at higher elevations which will sit over old windslab. Below tree line, incoming precipitation will fall as rain which will saturate the snowpack and make wet loose avalanches very likely in areas still holding snow. The mid-pack consists of multiple layers of dense wind effected snow, sun crusts, and facets. Depth hoar and basal facets make up the base of the snowpack.
Weather Summary
Sunday night
Periods of snow/rain.
Accumulation: 17 cm.
Alpine temperature: Low -7 °C.
Ridge wind southwest: 25 km/h gusting to 70 km/h.
Freezing 1900m.
Monday
Flurries.
Accumulation: 6 cm.
Alpine temperature: High -3 °C.
Mostly light ridge wind occasionally gusting to 45 km/h.
Freezing level: 1700 m
Tuesday
Flurries.
Accumulation: 6 cm.
Alpine temperature: Low -8 °C, High -3 °C.
Mostly light ridge wind occasionally gusting to 35 km/h.
Freezing level: 1700 m
Wednesday
Periods of snow.
5 to 10 cm.
Terrain and Travel Advice
- Minimize exposure during periods of heavy loading from new snow, wind or rain.
- If triggered loose wet avalanches may step down to deeper layers resulting in larger avalanches.
Avalanche Problems
Storm Slabs
Additional precipitation with strong SW winds will rapidly build storm slabs while adding to our wind slab problem on lee and cross-loaded features. This problem may extend into tree line if freezing levels are lower then current weather forecast predicts.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood: Likely - Very Likely
Expected Size: 1 - 2
Loose Wet
Weak overnight freezes, warm temperatures, and some rain / wet snow will keep this problem at the top of our list at tree line and below. Wet loose avalanches will likely step-down to our basal facets in steep terrain resulting in large avalanches
Aspects: All aspects.
Elevations: Treeline, Below Treeline.
Likelihood: Very Likely
Expected Size: 1.5 - 2.5
Deep Persistent Slabs
The bottom of the snowpack is inherently weak with well-developed Facets and Depth Hoar. Storm /Wind slabs or wet loose avalanches could trigger the deep persistent slab resulting in large avalanches.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood: Possible
Expected Size: 2 - 3.5