Avalanche Forecast

Archived

Feb 10th, 2022–Feb 11th, 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, 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

South Rockies.

Avoid overhead hazard. Solar input could increase the chances of cornice falls and wet loose avalanches on sun exposed slopes.

Confidence

High -

Weather Forecast

Thursday night: no new snow expected. Freezing levels falling to 1200m. Moderate norhtwest winds.

Friday: Sunny with freezing levels around 1700m. Light to moderate northwest winds.

Saturday: sunny with light to moderate northwest winds. Freezing level rising to 2200m.

Sunday: sunny with light west winds. Freezing level rising to 2000m.

Avalanche Summary

No new avalanches were reported over the past few days.

Snowpack Summary

A new melt-freeze crust is expected on solar aspects into the alpine and all aspects at lower elevations. This crust will likely break down and become moist as the sun comes out. Ongoing periods of strong westerly winds have formed wind slabs and large cornices in exposed terrain at higher elevations.

The January 30 interface is now typically down around 20cm and consists of a variety of forms including surface hoar, facets and a crust. It is generally only concerning in the north part of the region. The mid January crust is down 20 to 70 cm deep. In most of the region this crust may only be found on solar aspects. In heavily wind effected areas it may be found on the surface.

The early December crust/facet persistent weak layer is now 100-200 cm deep. This layer produced numerous very large avalanches in January but is now considered dormant. See this forecaster blog on how to manage this layer as it may come into play again later this season.

Terrain and Travel

Be careful as you transition into wind affected terrain.
Cornices become weak with daytime heating or solar exposure.
Avoid steep slopes when air temperatures are warm, or solar radiation is strong.

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.