Avalanche Forecast

Archived

Mar 9th, 2021–Mar 10th, 2021

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely.

Below Treeline

Natural avalanches unlikely.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely.

Below Treeline

Natural avalanches unlikely.

Regions

South Coast Inland.

Recent storm snow has been redistributed into pockets of wind slab at tree line and in the alpine and may continue to be reactive, particularly in the north of the region. Watch for denser, deeper drifts near ridge-crests and rollovers.

Confidence

Moderate - Uncertainty is due to how quickly the snowpack will recover and gain strength. Uncertainty is due to extremely variable snowpack conditions reported through the region.

Weather Forecast

TUESDAY NIGHT - Mainly cloudy with isolated flurries, up to 10 cm possible in the far south of the region / light west wind / alpine low temperature near -6

WEDNESDAY - Mainly cloudy with sunny breaks and isolated flurries / light north wind / alpine high temperature near -4 / freezing level 1000 m

THURSDAY - Mainly sunny / light west wind / alpine high temperature near -5 / freezing level 1200 m

FRIDAY - A mix of sun and cloud / light to moderate southwest wind / alpine high temperature near -2/ freezing level 1500 m

Avalanche Summary

In the north of the region:

There were a few reports of small dry loose avalanches on Monday.

There were several reports of small to large (up to size 2.5) storm slab avalanches releasing naturally on a variety of aspects and elevations during the weekend storm. One of these was thought to have been triggered by a cornice fall. Check out these MIN reports (here and here) from slopes near Chief Pascall. Small loose dry sluffs were also observed in steep terrain.

In the south of the region:

There were numerous reports of large (size 2-3) natural glide slab avalanches over the past week, including a few more on Monday. Glide slabs are most likely in areas of smooth ground cover such as rock slabs and can be large, involving the full depth of the snowpack. Carefully consider your access/egress routes where they cross under large paths.

Snowpack Summary

In the north of the region, 30-50 cm of new snow over the weekend was redistributed by recent strong south winds into wind slabs on leeward slopes that may remain possible to trigger. Massive cornices exist on ridgelines, which can also act as triggers on slopes below. Deeper in the snowpack, a weak layer of facets buried in mid-February may still be found on north aspects near treeline but has been gaining strength. The lower snowpack is generally well settled and strong.

The south of the region received trace accumulations of snow over the weekend with moderate wind. The danger ratings are Moderate, Low, Low, with a concern for small wind slabs. The snowpack is generally well consolidated with no concerns of buried weak layers but recent notable glide avalanche activity.

Terrain and Travel

Avoid freshly wind loaded features, especially near ridge crests, roll-overs and in steep terrain.
Watch for signs of instability like whumpfing, hollow sounds, shooting cracks or recent avalanches.
Minimize your exposure time below cornices.

Problems

Wind Slabs

Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.