Avalanche Forecast

Archived

Mar 21st, 2023–Mar 22nd, 2023

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely.

Below Treeline

Natural avalanches unlikely.

Alpine

Natural avalanches unlikely.

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

Lizard-Flathead, Akamina, Flathead, Lizard.

Watch for isolated pockets of wind slab at upper elevation. Avoid overhead exposure to cornices, especially during the heat of the afternoon.

Confidence

Moderate

Avalanche Summary

On Sunday, several natural size 1 loose wet avalanches were observed from steep terrain on solar aspects. A skier-triggered size 1.5 loose wet was reported in the late afternoon on a southeast aspect. A solar-triggered size 1.5 slab avalanche was also reported from a steep treeline feature.

On Saturday, a few natural size 1 wet loose avalanches were observed on alpine features that received direct sun in the afternoon.

If you head out in the backcountry, let us know what you are seeing by submitting a report to the Mountain Information Network.

Snowpack Summary

The snow surface includes a daily melt-freeze cycle on solar aspects, surface hoar up or facets in shady and wind-sheltered areas, and wind-affected surfaces in exposed terrain.

The top layer of the snowpack at higher elevations is made up of 20 to 40 cm of dense, wind-affected snow. It tapers to a rain crust below 1400 m. This Top layer of snow may sit on a sun crust on solar slopes and small surface hoar in sheltered, shaded areas.

The mid-snowpack is generally well-settled. The lower snowpack includes a layer of weak sugary crystals near the ground. This layer has not produced recent avalanche activity.

Weather Summary

Tuesday night

Clear. Alpine temperatures drop to a low of -5 °C. Light variable ridge wind. Freezing level at valley bottom.

Wednesday

Sunny. Alpine temperatures reach a high of 3 °C. Light variable ridge wind. Freezing level rises to 2000 metres.

Thursday

A mix of sun and cloud with isolated flurries. Alpine temperatures reach a high of 2 °C. Ridge wind 10 to 40 km/h from the southwest. Freezing level rises to 1800 metres.

Friday

Cloudy with sunny periods and isolated flurries. Alpine temperatures reach a high of -3 °C. Ridge wind light from the southwest. Freezing level rises to 1200 metres.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

Be careful with wind slabs, especially in steep, unsupported and/or convex terrain features.
Recent wind has varied in direction so watch for wind slabs on all aspects.
Avoid slopes when the solar radiation is strong, especially if they have large cornices overhead.

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.