Avalanche Forecast

More of the same weather is expected for Sunday, mostly sunny and warm with light winds. 

In areas away from the lower elevation passes, many NWAC weather stations have seen temperatures reaching the low 50's Saturday and similar conditions are expected Sunday.

Surface melt-freeze crusts should form overnight on solar exposed slopes and gradually melt through the day. Loose wet avalanches should be less likely Sunday and mainly confined to steep sun exposed slopes below rocks or trees absorbing abundant radiation. Watch for terrain such as this if the surface snow is melting more than a few inches. 

Older wind slabs should have mostly settled and stabilized and will be removed from the avalanche problem list, but continue to look out for areas of wind stiffened snow deposited mainly near ridges on steep shaded terrain.

Early season terrain hazards still exist, such as poorly covered rocks, vegetation and creeks, particularly at lower elevations.

High pressure has now been over the region for a full week. Sunshine and very mild temperatures have been the story with cooler temperatures at lower elevations. This weather has allowed for overall strengthening and consolidation of an already strong snowpack.

Some small loose wet slides have occurred on mainly steep sun exposed slopes through the week, but have become less frequent over the past few days.

At the beginning of the high pressure, strong easterly crest level wind early in the week transported loose snow and built wind slab layers, producing a few triggered size 1-1.5 avalanches mainly near or above treeline. No triggered wind slabs have been reported since Tuesday as these older wind slabs continue to settle and bond under warm temperatures. Older wind slabs may still persist, mainly near and above treeline on mostly westerly to northerly facing terrain, especially below ridges. These slabs should be more reluctant to trigger as they continue to bond and strengthen. 

The surface snow consists mainly of surface melt freeze crusts forming overnight on solar aspects, On shaded aspects, settled storm snow is still providing some nice skiing and riding conditions.  

The total snowpack height in these zones varies mostly from 3-5 feet, with the most over the volcanic peaks.

The snowpack is well consolidated and strong with settled old storm snow of about 1.5-2.5 feet over the strong Thanksgiving rain crust. 

During this high pressure pattern, surface hoar and or surface facets have been formed, and grown quite large in some areas, especially the typical sun and wind sheltered terrain at lower elevations in the cooler temperatures below the inversion. We will need to watch for these potential weak surface snow conditions as they may have an impact on future avalanche conditions when snowfall returns. 

Observations

North

Mt Baker ski area snow safety on Saturday reported no avalanche activity and relates a strong and settled snowpack. Loose wet avalanche activity has diminished over the past few days.

On Thursday the Baker pro-patrol reported appliance sized chunks of snow and ice releasing from rocks in the sun, but no other activity.  

Wind loading reported above treeline on Tuesday was not observed on Wednesday.

Central

Numerous recent reports over the past few days indicate creamy settled storm snow still providing nice skiing and riding conditions on sun sheltered aspects.

Thursday and Friday the Alpental pro-patrol saw minor roller balls and point releases on steep solar slopes and cold snow on non-solar slopes. Good bonds were seen on the Thanksgiving crust down 67 inches near mountain top.

A report via the NWAC Observations for Stevens on Tuesday indicated a favorable snow density profile (gradually increasing with depth) on non-solar slopes, moderate to hard tests in recent snow and a good bond to the T Day crust.

South

Friday the Crystal pro-patrol reported only a few roller balls on steep solar slopes that were not entraining snow, with some previously scoured areas getting melted to the ground.

NWAC staff avalanche training at Mt Rainier Thursday reported an overall strong snowpack on westerly aspects of Mazama Ridge near Paradise. At 5400 feet the height of snow was about 4 feet with the Thanksgiving crust well bonded about 2 feet below the surface. Settled storm snow with few remaining storm layers provided nice conditions on non-solar aspects. Previous wind effected snow was visually evident on exposed slopes near and above treeline but not visited.

The Crystal pro-patrol on Wednesday reported east winds has stripped the snow along windward ridges, but little snow remained for significant transport. Settled powder remained on northerly aspects not wind buffed.