Avalanche Forecast
Issued: Mar 16th, 2021 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs.
JSmith,
Avalanche Canada
Southwesterly winds continue to form wind slabs on lee and cross-loaded terrain features in the alpine. Use caution when transitioning into wind affected terrain and avoid wind loaded slopes below ridgetops.
Summary
Confidence
Moderate - Uncertainty is due to the limited number of field observations.
Weather Forecast
 Â
TUESDAY NIGHT: Partly cloudy with isolated flurries; 0-5 cm. / Moderate, southwest ridgetop wind / alpine low temperature -8 / Freezing level 800 m.
WEDNESDAY: Mostly cloudy with isolated flurries; 0-5 cm. / Strong, southwest ridgetop wind / alpine high temperature -2 / Freezing level 1000 m.
THURSDAY: Mix of sun and cloud / Moderate, southwest ridgetop wind / alpine high temperature -1 / Freezing level 1200 m.
FRIDAY: Mostly cloudy with isolate flurries; 0-3 cm. / Strong, southwest ridgetop wind / alpine high temperature -3 / Freezing level 1000 m.
Avalanche Summary
No new natural avalanches and a few size 1 skier triggered wind slab avalanches in the alpine were reported on Monday.
A natural avalanche cycle with storm slab avalanches up to size 2.5 were reported in the southwest of the region throughout the weekend.Â
Snowpack Summary
5-10 cm of new snow adds to the 15-20 cm of storm snow over the weekend, except for the southwest of the region where weekend storm totals range between 50 and 100 cm. Recent southerly winds are forming fresh wind slabs on lee features below alpine ridgetops. At lower elevations the precipitation fell as rain.Â
The new snow overlies a variety of surfaces including hard wind affected snow at alpine elevations, weak, surface hoar crystals on northerly aspects and in sheltered terrain features around treeline, or a melt-freeze crust on southerly aspects and below treeline.
The mid and lower snowpack is reported as well settled and strong in most areas. However, weak facets exist at the base of the snowpack in the more shallow snowpack zones within much of the region and always have the potential of being triggered on steep, rocky slopes with a shallow or thin to thick snowpack; especially with large loads such as a cornice fall.
Terrain and Travel
- Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
- Watch for signs of instability like whumpfing, hollow sounds, shooting cracks or recent avalanches.
- Potential for wide propagation exists, fresh slabs may rest on surface hoar, facets and/or crust.
- Avoid exposure to slopes that have cornices overhead.
Problems
Wind Slabs
Southwesterly winds continue to form wind slabs that may be reactive to human triggers on lee and cross-loaded terrain in the alpine.
Recently formed slabs may be sitting on a weak layer of surface hoar on northerly aspects and in sheltered terrain or a crust on solar aspects and lower elevations.
Aspects: North, North East, East, North West.
Elevations: Alpine.
Likelihood
Expected Size
Valid until: Mar 17th, 2021 4:00PM
