Avalanche Forecast
Issued: Jan 12th, 2021 4:06PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Storm Slabs, Persistent Slabs and Loose Dry.
Lisa Paulson,
An intense storm tonight and into Wednesday morning will cause an increase in avalanche hazard. Avoid avalanche terrain Wednesday.
Summary
Weather Forecast
20-40 cm forecasted overnight and Wednesday morning with strong S-SW wind. Temperatures will remain warm for much of the storm which will promote rapid slab formation and cornice growth. The cold front moves through the region Wednesday morning with temperatures dropping, winds easing and precipitation stopping by noon on Wednesday.
Snowpack Summary
The recent storm snow coupled with strong S-SW winds may not bond well to underlying surfaces. Below this, there are three persistent weak layers from Dec are down 30-100 cm that may become touchy with critical loading, The Nov. 5 basal crust/facets may also become reactive with the in areas that receive rapid loading from the storm.
Avalanche Summary
No new avalanches reported Tuesday. Yesterday, climbers triggered a size 1 slab enroute to their climb in Balfour Creek. Over the past few days on Mt. Field, there was one cornice triggered size 2 slab avalanche was observed in the alpine and a triggered size 0.5 slab in a very steep open glade just below treeline.
Confidence
Timing, track, or intensity of incoming weather system is uncertain
Problems
Storm Slabs
We expect 20-40 cm with strong SSW wind. The snow will quickly form both storm and wind slabs with the influence of warm temperatures. The storm snow is not expect to bond well to the underlying surface of facets or surface hoar.
- Choose low angle and supported terrain. Avoid large features.
- Use caution in lee areas. Recent wind loading have created wind slabs.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Persistent Slabs
These layers may become more reactive with the storm. Three persistent weak layers from Dec exist in the top 100 cm of the snowpack. They continued to produced sudden results and had a couple of skier triggered avalanches on them in the past week.
Aspects: All aspects.
Elevations: Treeline, Below Treeline.
Likelihood
Expected Size
Loose Dry
Expect loose dry avalanches off steep terrain tomorrow as the new snow will sluff easily and may trigger a slab avalanche on the slopes below.
- Minimize overhead exposure during periods of heavy loading from new snow, wind.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Jan 13th, 2021 4:00PM
