Avalanche Forecast

Archived

Mar 5th, 2022–Mar 6th, 2022

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.

Treeline

Natural avalanches unlikely.

Below Treeline

Natural avalanches unlikely.

Regions

Northwest Inland.

Warm temperatures and strong to extreme west wind are forecast. This will increase the likelihood of cornice failures and build fresh wind slabs. It is uncertain whether the buried persistent weak layers will wake up with the forecast weather.

Confidence

Moderate - Uncertainty is due to how buried persistent weak layers will react with the forecast incoming weather.

Weather Forecast

Saturday night: Cloudy with some clear periods, trace of new snow, moderate northwest wind, alpine temperature 0 °C, above freezing layer between 1300 m and 2000 m in the south of the region.

Sunday: A mix of sun and clouds, up to 2 cm snow, strong to extreme west wind, alpine high 0 °C, freezing level dropping to 1500 m in the south of the region, and at around 1000 m in the north of the region.

Monday: Mainly sunny, up to 3 cm snow, moderate northwest wind, alpine high -8 °C, freezing level around 700 m.

Tuesday: Mix of sun and clouds, trace of new snow, light to moderate northeast wind, alpine high -12 °C, freezing level at valley bottom.

Avalanche Summary

Small loose wet avalanche were reported on Friday.

The field team reported 2 slab avalanches that had been triggered by cornices earlier in the week. Check out the MIN here.

Snowpack Summary

40-60 cm of well settled and bonded snow sits on top of the mid-February crust. Though this layer has not produced avalanche activity, professionals in the area are still treating it with suspicion. The upper snowpack is moist below 1500 m due to warm temperatures. Cornices are looming in alpine areas.

The lower snowpack is well bridged by the mid-February crust and triggering avalanches below this layer is unlikely at this time.

Terrain and Travel

Fresh wind slabs will likely form throughout the day, diligently watch for changing conditions.
Avoid exposure to slopes that have cornices overhead.
Cornice failure may trigger large avalanches.
As surface loses cohesion due to melting, loose wet avalanches become common in steeper terrain.

Problems

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.

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 Wet

Loose Wet avalanches are the release of wet unconsolidated snow or slush. These avalanches typically occur within layers of wet snow near the surface of the snowpack, but they may quickly gouge into lower snowpack layers. Like Loose Dry Avalanches, they start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-wet avalanches include point-release avalanches or sluffs. Loose Wet avalanches can trigger slab avalanches that break into deeper snow layers.