Avalanche Forecast
Issued: Mar 27th, 2020 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs and Deep Persistent Slabs.
JSmith,
Avalanche Canada
Small wind slabs below ridgetops are currently the primary concern.
Summary
Confidence
Low - Uncertainty is due to the limited number of field observations.
Weather Forecast
FRIDAY NIGHT: Cloudy, moderate west winds, alpine low -5 C, freezing level 1000 m.
SATURDAY: Cloudy with isolated flurries; 0-3 cm, strong southwest winds, alpine high 1 C, freezing level 1800 m.
SUNDAY: Snow; 5-10 cm, strong southwest winds, alpine high 1 C, freezing level 1800 m.
MONDAY: Snow; 5-10 cm, moderate southwest winds, alpine high -1 C, freezing level 1500 m.
Avalanche Summary
There are currently very few professional operations reporting in this region and the data stream is very limited.
Over a week ago, there was a report of a skier remotely triggering (from a distance) a large (size 2) deep persistent slab avalanche at 2600 m on a northwest aspect. The avalanche was triggered from a thin spot, released 40-80 cm deep, and ran on depth hoar near the base of the snowpack.
Snowpack Summary
NOTE:We are receiving very limited professional snowpack observations in this region. The snowpack summary below is based on our most recent observations and weather data.
The recent snow sits on a variety of snow surfaces, consisting of sun crusts, hard wind-affected snow, and soft faceted snow. There have also been reports of surface hoar forming on sheltered, shady slopes. See this MIN for a helpful illustration from nearby Glacier National Park. It will be important to track the depth, cohesiveness, and bond of the new snow to these various old snow surfaces across aspects and elevations where you are travelling.
Cornices are large and looming. Surface hoar buried February 22 may be found 50-100 cm deep. Avalanche activity on this layer was last reported March 11th.Â
Deeply buried facets lurk near the bottom of the snowpack. This layer has been responsible for sporadic deep persistent slab avalanches, usually triggered from shallow, rocky start zones.
Terrain and Travel
- Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
- Avoid shallow, rocky areas where the snowpack transitions from thick to thin.
- Make observations and assess conditions continually as you travel.
- Be alert to conditions that change with aspect and elevation.
- Cornice failure may trigger large avalanches.
Problems
Wind Slabs
Strong winds may form small wind slabs on lee features below ridgetops.
Aspects: North, North East, East, South East.
Elevations: Alpine.
Likelihood
Expected Size
Deep Persistent Slabs
Weak faceted snow near the base of the snowpack continues to be a concern. Treat wind-scoured, rocky, shallow terrain as suspect and avoid big alpine slopes that are threatened by cornices overhead.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Mar 28th, 2020 5:00PM
