Avalanche Forecast

The next strong cool cold front will cross the Northwest Saturday night and Sunday morning. This will renew moderate to heavy snow in the Olympics and Cascades Saturday night and Sunday morning with a minor warming trend but the snow level will stay below the passes. It looks like the heaviest snow will shift to Oregon Sunday.

Rapid loading will cause new storm and wind slab to build Saturday night and Sunday. Natural storm and wind slab should be possible and triggered storm and wind slab should be likely during the main part of the storm Sunday morning in the above treeline and near treeline. These conditions could easily last all day Sunday.

Terrain anchors are still causing significant anchoring at the lowest elevations. Use caution near creeks which are still open in some areas.

Heavy rain transitioned to snow around Dec 9th along the east slopes leaving a rain crust up to at least 6000 feet in the north Cascades and near or above 7000 feet in the central and south.

A series of cool storms since then has deposited increasing storm snow at relatively low freezing levels. There has been about .5-1.5 feet of snowfall at sites along the east slopes the past 2-3 days. Snow depths below treeline are increasing nicely, but many barely hidden hazards like rocks, streams or snags remain. The skiing in non-wind affected areas with enough snow cover has been good! 

NWAC pro observer Tom Curtis was at Rainy Pass near Stevens Pass on Wednesday and noted extensive surface hoar. This layer may have been buried intact Thursday though no evidence of avalanches on a surface hoar layer has been reported through Saturday.

Tom visited Mt Cashmere via the Icicle Creek drainage Thursday and did not find the persistent layer of buried surface hoar seen prior to the rain event December 8-9. There has been good evidence that the rain event destroyed this layer along the east slopes so the PWL has been removed as an avalanche problem along the east slopes. Tom did note small storm and wind slab up to near treeline but did not venture higher.

A guide report from Thursday at Washington Pass zone indicated good snow and good stability at the elevation of the highway hairpin with blowing snow along the ridge tops.  

The southeast zone should have a much shallower snowpack, more affected by recent rain and warm temperatures. However, we have no recent observations from the southeast zone.