Avalanche Forecast

Issued: Mar 14th, 2021 4:00PM

The alpine rating is moderate, the treeline rating is low, and the below treeline rating is low. Known problems include Wind Slabs.

Avalanche Canada ldreier, Avalanche Canada

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Temperatures are cooling overnight. The remaining concern is isolated wind slabs in the alpine. Even small avalanches can have serious consequences in extreme terrain.

Summary

Confidence

High - We have a good understanding of the snowpack structure and confidence in the weather forecast

Weather Forecast

SUNDAY NIGHT: Cloudy, up to 5 cm new snow, 30 km/h southwest wind, alpine low -5 C, freezing level lowering to 1000 m. 

MONDAY: Mix of sun and cloud, trace of new snow, 10 km/h northwest wind, alpine high -1 C, freezing level 1600 m.

TUESDAY: Sunny, 20 km/h westerly wind, alpine high 4 C, freezing level 1900 m.

WEDNESDAY: Sunny, 20 km/h southeast wind, alpine high 5 C, freezing level 2000 m.

Avalanche Summary

Numerous natural and explosives triggered wet loose avalanches up to size 3 on steep solar aspects were reported on Sunday. A large cornice failure (size 2.5) was observed and did not trigger a slab on the slope below. 

Numerous natural wet loose avalanches up to size 2.5 were observed on solar aspects as well as on polar aspects up to 2100 m on Saturday. Several cornice failures up to size 2.5 during the heat of the day were reported. The cornices did not trigger slabs on the slopes below. A large glide snow avalanche (size 2.5) released naturally. Explosives triggered a persistent slab avalanche of size 3 in the southeast of the region. 

Small size 1 naturally triggered wind slabs on north aspects and size 1 wet loose avalanches on solar aspects in the alpine were reported on Friday.

On Thursday, a skier triggered a size 2 storm slab avalanche on a southeast aspect in the alpine. The sun had warmed around 20 cm of convective new snow just enough to react as a soft slab on a steep, convex feature.

Snowpack Summary

10-20 cm of recent convective snow and moderate westerly winds have formed fresh wind slabs below alpine ridgetops. Sunny skies and warm temperatures formed sun crusts on solar aspects at all elevations and up to 2000 m on polar aspects. Dry snow still exists on north aspects at upper elevations. Large cornices loom over alpine ridgetops.

Persistent weak layers of surface hoar, crusts, and/or facets 80-120 cm down have recently been unreactive except for an explosives triggered avalanche in the southeast of the region on Saturday. 

Terrain and Travel

  • Watch for wind-loaded pockets especially around ridgecrest and in extreme terrain.
  • Small avalanches can have serious consequences in extreme terrain. Carefully evaluate your line for wind slab hazard before you commit to it.

Problems

Wind Slabs

An icon showing Wind Slabs

Recent convective flurries in parts of the region and light to moderate winds may have formed reactive slabs in isolated alpine locations. Steep, convex slopes below alpine ridgetops are the most likely places to trigger these slabs.

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Unlikely - Possible

Expected Size

1 - 2

Valid until: Mar 15th, 2021 4:00PM