Avalanche Forecast

Additional snow and wind on Saturday will continue create dangerous avalanche conditions along the east slopes of the Cascades.

Winds will continue to form sensitive wind slabs on a variety of aspects. Strong winds may deposit snow and form wind slabs lower downslope and at lower elevations than normal. Identify and avoid areas of wind deposited snow such as below fresh cornices and on snow drifts.

New shallow and sensitive storm slabs will develop Friday night into Saturday morning in areas that receive higher precipitation amounts in the northern part of the forecast area. Avalanches may trigger on steeper slopes and convex rollovers. Identify and avoid slope features where you are more likely to trigger an avalanche.

Uncertainty still exists around the distribution of buried surface hoar. Travel with caution and ease into terrain if traveling in areas further east of the Cascade crest.

Cornices have grown large over the past week. Give them a wide berth as they can break much farther back from the ridge than anticipated. Consider overhead cornice hazard while traveling and avoid spending time below large cornices.

An active storm period has deposited new snow across the east slopes of the Cascades over the last several days. Near Washington Pass, 20 inches of settled snow sits over the 1/16 crust. Further south and east lesser amounts of snow have been recorded. (10 inches in the Lake Wenatchee area and 6 inches at Mission Ridge and Blewett Pass)

Winds throughout the storm cycle have redistributed snow forming wind slabs on a variety of aspects.

Several weak layers can be found within the storm snow. Observations demonstrate most of these layers gaining strength.

Observations from around the east slopes central and north found buried surface hoar above the 1/16 crust. There is still quite a bit of uncertainty around the distribution of this layer. Extra caution should be taken when traveling in areas further east  of the crest or in areas where less snow has been received.

Snowdepth still decreases substantially east of the Cascade crest. In many areas below treeline, there has not been enough snow to present an avalanche danger.

Observations

North

On Thursday and Friday, NCH observed evidence of several recent wind slabs that had released in steep terrain above treeline in the Washington Pass area. Away from wind affected terrain and in several snowpits, a generally stable and right-side-up upper snowpack was noted. 

Wednesday, Jan 24th, NCMG observations on Delancy Ridge found nearly 3 ft of low cohesion storm snow in sheltered terrain below treeline with no avalanches noted. No reactivity was found at the 1/16 interface with the melt-freeze crust.

On Monday, snowpit tests by a snow professional on a SE aspect near treeline in the Twisp River Valley gave sudden collapses within faceted grains below the 1/16 crust. Test results on a NE aspect yielded consistent sudden planar results above the 1/16 crust with partially decomposed surface hoar on the interface.

NWAC received a second-hand report of a large skier-triggered avalanche on west-facing slope (likely near treeline) on Abernathy Peak in the upper Twisp River drainage. The avalanche propagated widely and was suspected to have failed on the 1/16 crust.

Central

A public observation from Wednesday in the Blewett Pass area identified basal facets at the bottom of the snowpack and surface hoar above the most recent crust. Snow cover was still regionally low in this area. Small skier triggered wind slabs were noted and rain briefly reached up to 5000' Wednesday morning.

Buried surface was found in the Icicle Creek drainage over the 1/16 crust over a week ago up to 6800 ft. 

South

No recent observations