Avalanche Forecast

Archived

Dec 4th, 2019–Dec 5th, 2019

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.

Treeline

Natural avalanches unlikely.

Below Treeline

Natural avalanches unlikely.

Regions

Northwest Inland.

Snow accumulation has varied across the region following the recent storm. In areas with higher snow totals, avalanches are possible where winds have transported the recent snow into slabs on lee terrain features.

Confidence

Low - Uncertainty is due to the limited number of field observations.

Weather Forecast

Wednesday night: Partly cloudy, isolated flurries with 1-3 cm of snow possible, moderate west winds, alpine temperature -10 C

Thursday: Cloudy with periods of sun, isolated flurries with a trace of precipitation, light variable winds, alpine high temperature -8 C

Friday: Mix of sun and cloud, no precipitation, light variable winds, alpine high temperature -10 C

Saturday: Mix of sun and cloud, no precipitation, light variable winds, alpine high temperature -11 C

Avalanche Summary

There have been no recent reports of avalanches in the region; however, there is very little information available at this time. If you get out into the mountains, let us know what you see by submitting to the Mountain Information Network!

Snowpack Summary

Snowfall has been sporadic and failed to materialize with the last storm system. Since the weekend, areas further north in the region have accumulated 5-10 cm. In these areas, southwesterly winds have been transporting the snow into wind slabs on lee features at upper elevations. Depending on location, these slabs are likely sitting on a mix of sugary faceted snow, and feathery surface hoar crystals, and hard wind-affected snow that may be reactive to human triggering.

Total snowpack amounts are likely in the 60-120 cm range, tapering quickly at lower elevations.

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.