Avalanche Forecast

Archived

Mar 25th, 2022–Mar 26th, 2022

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely.

Below Treeline

Below Threshold.

Alpine

Natural avalanches unlikely.

Treeline

Natural avalanches unlikely.

Below Treeline

Below Threshold.

Alpine

Natural avalanches unlikely.

Treeline

Natural avalanches unlikely.

Below Treeline

Below Threshold.

Regions

Yukon.

Carefully assess steep lines for wind slabs and limit exposure to cornices.

Confidence

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

Weather Forecast

Friday night: Low of -12 at 1100 m. Light flurries bringing trace amounts of new snow with light to moderate southerly winds.

Saturday: Mostly sunny. Light southwest wind. High of -3 at 1100 m.

Sunday: Mostly sunny with light southwest wind. High of -5 at 1500 m.

Monday: A mix of sun and cloud with the possibility of light flurries bringing trace amounts of new snow. Light to moderate southwest winds. High of -5 at 1500m.

Avalanche Summary

Avalanche activity has been minimal. A size 1.5 wind slab out of a steep couloir feature was the only report in the White Pass area on Thursday.

We suspect small wet loose avalanches could be observed on solar aspects if the sun comes out.

Snowpack Summary

Around 50 cm of recent snow is settling and bonding well. Wind slabs can be found near ridge tops, below convexities and in steep or extreme terrain in the alpine. Moist snow could be observed on solar aspects if the sun comes out.

A couple of sun crusts exist in the upper snowpack but none have been identified as layers of particular concern. The lower snowpack is thought to be well protected by the dense, wind-pressed layers above, and it is unlikely that avalanches will be triggered on weak, sugary crystals near the ground at this time.

Terrain and Travel

Be careful with wind slabs, especially in steep, unsupported and/or convex terrain features.
Avoid exposure to slopes that have cornices overhead.
Even small cornices may have enough mass to be destructive and deadly.

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.

Cornices

Cornice Fall is the release of an overhanging mass of snow that forms as the wind moves snow over a sharp terrain feature, such as a ridge, and deposits snow on the downwind (leeward) side. Cornices range in size from small wind drifts of soft snow to large overhangs of hard snow that are 30 feet (10 meters) or taller. They can break off the terrain suddenly and pull back onto the ridge top and catch people by surprise even on the flat ground above the slope. Even small cornices can have enough mass to be destructive and deadly. Cornice Fall can entrain loose surface snow or trigger slab avalanches.