Avalanche Forecast

Archived

Feb 5th, 2021–Feb 6th, 2021

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

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, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Regions

Little Yoho.

Carefully assess the wind slab problem before committing to big terrain. Though natural avalanche activity has decreased, skier triggering of this problem remains a concern.

Weather Forecast

Overcast skies and light snow is expected over the weekend. An arctic ridge will move into the forecast region by Sunday resulting in cold temperatures and decreased wind values. The arctic air will remain in place until Friday next week.

Snowpack Summary

Moderate to strong Westerly winds have redistributed the recent 30-60cm of low density storm snow into wind slab in the alpine and exposed areas at tree line. In sheltered areas the recent storm snow remains loose powder. The mid snowpack has a series of persistent weak layers that remain dormant. Height of snow at tree line is 150-220 cm.

Avalanche Summary

Natural avalanche activity has tapered since the peak of the storm on Tuesday. Explosive control work has continued to produce avalanches to size 2.5 in areas where newly formed wind slabs exist.

Confidence

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.

Loose Dry

Loose Dry avalanches are the release of dry unconsolidated snow and typically occur within layers of soft snow near the surface of the snowpack. These avalanches start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-dry avalanches include point-release avalanches or sluffs.