Avalanche Forecast

Partial clearing to the north and mostly clear skies to the south should allow for a good refreeze Saturday night. Sunday should be a fair weather day with temperatures similar or a few degrees warmer than Saturday. Sunshine is expected to be filtered at times with high clouds from the next approaching system. Expect the biggest change in temperatures and solar input to be found for the north Cascades whom saw mostly cloudy skies and cooler temperatures Saturday.    

The equinox has passed and we've officially moved into spring; wet loose avalanches remain possible on sun exposed terrain, especially mid and lower elevations in the late morning and afternoon hours. Watch for wet surface snow deeper than a few inches, pinwheeling of surface snow and small natural wet loose releases that usually precede more major wet loose snow avalanches.

Wet loose concerns should be heightened in the north Cascades where less solar input was received Saturday and there may be a few inches new snow available for a generally small slide. 

Recent storm slabs instabilities should be settled out by now. However, continue to watch for lingering but likely isolated wind slab on lee north through easterly slopes near and above treeline. Watch for cracking or firmer wind transported snow in steep exposed terrain. A large cornice fall could provide the right natural trigger for a wind slab to release on a lee slope.  

Preliminary Granite Mountain Accident Information as of early Sunday morning: Around 4:45 PM on Saturday afternoon 2 skiers and a dog descending the looker's left (or skier's right) avalanche path on the south side of Granite Mt (visible from I-90) triggered an initially small slab avalanche (estimated 6" crown) that stepped down to possibly 2-3 feet.  The skiers were in the heart of the avalanche path on a steep (40+ degrees) slope, although the exact elevation is not known yet. This slab became large and destructive and ran down to 2500' where there is little snow cover.  Initial estimates are at least D3/R3.  One person was in a safe zone and not affected. The skier who triggered and was caught in the slide is still missing with ongoing search and rescue efforts expected Sunday. Another party of two nearby was not caught and aided in the preliminary search efforts.    

Minor changes have been made to the avalanche forecast for Sunday but the danger rating remains the same.  Moderate avalanche danger means heightened avalanche conditions on specific terrain features and that human triggered avalanches are possible while natural avalanches are unlikely.  Please use caution when dealing with wet snow concerns in the afternoon during peak daytime heating in the spring.  

More info will be relayed when it becomes available. 

----------------------------------------------------------------------------------------------------

Recent Weather and Avalanches over the last week

We have shifted avalanche concerns to the more recent storm layers and moved away from deeper snowpack concerns for the near term.

A wet front last weekend stalled over the Olympics and the north Cascades producing mainly rain before changing to snow in a north to south fashion across the area. A favorable temperature trend with gradual cooling occurred with this storm. NWAC sites along the west slopes picked up 5-20 inches of snow last weekend through Monday. Some storm and wind slab avalanches were seen following the last front but instability was not widespread due to the cooling trend, good bonding to the old snow surface and short lived storm layers. The new snow was generally reported to be over wet snow in the upper snow pack, with numerous reports of wet snow reaching down to 1 meter or greater in depth in snowpits.  

The latest cold front crossed the Northwest late Wednesday. This caused increasing winds, rain and snow and a cooling trend on Wednesday and deposited mainly 3 to 16 inches of new snow by Thursday morning, with the highest totals from NWAC stations at Mt. Baker and the top of Alpental. Lesser amounts were seen further south of Snoqualmie Pass. Temperatures remained cool Thursday with a few light snow showers. Reports from Alpental pro patrol Thursday AM indicated shallow soft storm slabs easily releasing from ski cuts and explosives. There had been a limited but noted natural avalanche cycle Wednesday night.  By Thursday midday some shallow daytime warming effects were creating slightly increased surface slab character as low density surface snow began consolidating.

NWAC received a report about an accident that occurred early Thursday afternoon. The second skier entering a steep chute triggered a 6-8" soft slab that broke 75" across within the recent storm snow in a chute called Fleur di Lis in the Mill Valley area of Stevens Pass. The first skier was in a safe area and the person who triggered the slab was caught and carried, lost gear, but fortunately was uninjured, ending on top of the debris surface. The crown released near the chute entrance at the top at roughly 5400 ft on a mainly NNW aspect. 

NWAC observers Dallas Glass near Paradise, MRNP Thursday and Jeff Ward at Jim Hill near Stevens Pass on Friday saw evidence of recent wind affects producing wind slab on some exposed lee N through E aspects near treeline and small wet loose on more solar aspects. Recent storm layer failures from snowpit tests were not particularly reactive and are expected to have settled over the last few days. See more of Jeff's observations from Friday in this video.  Backcountry reports on the NWAC observation page from Ruby Mtn Friday told a similar story with mainly well bonded snow but some storm snow instabilities still lingering 25-30 cm down near treeline and 1 small skier triggered soft slab on a convex roll on this layer near the summit.  Jeff Hambelton reported from the Stevens Pass area Friday of a natural shallow soft slab that released due to daytime heating on a west aspect near treeline (5600 feet). 

Friday was partly cloudy and cool and Saturday featured decreasing cloud cover from north to south along the crest along with warmer temperatures relative to Friday. Very light rain and snow were seen in the Olympics and north Cascades Saturday. Reports of thin surface hoar were reported Friday and Saturday morning...with more surface hoar growth possible Saturday night if skies remain or become clear.