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Avalanche Forecast

Archived

Feb 7th, 2014–Feb 8th, 2014

Alpine
Natural avalanches unlikely.
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.
Treeline
Natural avalanches unlikely.
Below Treeline
Natural avalanches unlikely.

Regions

Northwest Coastal.

Confidence

Fair - Timing, track, or intensity of incoming weather system is uncertain on Monday

Weather Forecast

Saturday: Mainly sunny. Light alpine wind with strong outflow wind likely valleys. Freezing level at valley bottom with alpine temperature reaching -15 C. Sunday: Sunny with cloudy periods. Light alpine wind. Freezing level at valley bottom with alpine temperature reaching -13 C. Monday: Increasing cloud with light snow possible in the afternoon.

Avalanche Summary

Reports from Thursday include natural and artificially triggered cornice falls to Size 2.5 with only 1 Size 1 wind slab triggered on the slope below. The faceted surface snow is also sluffing readily in steep terrain with skier traffic.

Snowpack Summary

A highly variable snow surface includes surface facets, surface hoar, thin wind slabs, and scoured crust, or any combination thereof. Remember to take stock of current surface conditions if you're out in the mountains. Once buried by a cohesive slab, surface hoar or a thin layer of facets sitting on a crust almost always becomes a weak layer, and will often persist.In sheltered areas, large surface hoar is growing on approximately 10cm of faceted old storm snow sitting on the late January crust, which is likely faceted and laminated and could have surface hoar on top. The entire snowpack is likely faceting to some degree, especially where it is shallow. Basal facets and depth hoar are likely, but triggering is only a concern in thin and variable snowpack areas with large triggers.

Problems

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.

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.