Avalanche Forecast
Issued: Jan 27th, 2020 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs.
astclair,
Avalanche Canada
Ongoing flurries and wind maintain wind slabs as a concern on Tuesday. Seek out sheltered slopes and watch for reactive pockets around steep rolls and ridge features.
Summary
Confidence
High - Confidence is due to a stable weather pattern with little change expected.
Weather Forecast
Monday night: Cloudy, isolated flurries, light to moderate southwest winds, alpine temperature -5 C.
Tuesday: Mix of sun and cloud, a trace of new snow, light to moderate southwest winds, alpine high temperature -2 C, freezing level around 1300 m.
Wednesday: Mix of sun and cloud, moderate southwest winds, alpine high temperature -2 C, freezing level around 1300 m.
Thursday: Mostly clear, light southwest winds, alpine high temperature -1 C, freezing level around 1500 m.
Avalanche Summary
Over the past several days, there have been reports of natural, human-triggered, and explosive triggered avalanches up to size 2.5 breaking in the new storm snow, specifically where it has been drifted by wind into stiffer slabs on northwest through northeast aspects. A couple of these avalanches have been reportedly triggered by cornice fall.
Snowpack Summary
Southwest winds have drifted 20-30 cm of recent snow into slabs on lee and cross-loaded terrain features at upper elevations. This combination has also contributed to cornice growth, increasing the need for vigilance with overhead hazard. A temperature crust formed Friday at least as high as 1600 m.
The stout upper snowpack continues to settle in mild temperatures. Several crust layers exist in the mid-pack as a result of previous warming and rain events. These have not been identified as bed surfaces or failure planes in recent avalanche activity.
The bottom 10-20 cm of the snowpack consists of faceted snow and decomposing crusts. Although inherently weak, this basal layer has not been an active avalanche problem in the region since December.
Terrain and Travel
- Be alert to conditions that change with elevation, aspect and exposure to wind.
- Watch for wind-loaded pockets especially around ridgecrest and in extreme terrain.
- Pay attention to cornices and give them a wide berth when traveling on or below ridges.
Problems
Wind Slabs
Recent snow and southwest winds have formed slabs on lee features in the alpine and exposed ridges near treeline. While natural avalanche activity has tapered, human triggering may still be possible. The wind slab problem overlaps with areas where cornices are also a concern.
Aspects: North, North East, East, South East, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Jan 28th, 2020 5:00PM
