Avalanche Forecast

Becoming cloudy Saturday with occasional very light snow, mainly during the afternoon. Only light amounts of new snow are expected through the day Saturday, if any. Winds should be mostly southerly and light. 

Moderate to locally strong E-NE winds Tuesday night and Wednesday have loaded unusual aspects and built wind slab in all elevation bands, especially in the south and central Cascades affecting locations such as Snoqualmie Pass, Crystal Mountain, Paradise and White Pass.  These wind slabs continue to heal and bond, but the cold temperatures are slowing that process. 

Watch for lingering wind slabs and avoid terrain where even a small slab avalanche could have unintended consequences. Remember to watch for firmer wind transported snow on all slope aspects or cross loaded slopes, especially in areas with varied terrain and modified wind directions. . 

Weather and Snowpack

A low pressure system moved across western Washington on Saturday night, followed by cold Arctic air. NWAC stations along the west slopes picked up 5-13 inches of snowfall by New Year's Day with W-SW winds.

An unusual reverse orographic east flow caused snow mainly in the central to south Cascades Sunday afternoon and night. NWAC stations along the west slopes added another 1-10 inches of snow on Monday morning with the most snow in the central to south part and further cooling.

Fair cold weather with moderate east winds were seen on Monday and Tuesday. Fair and cold weather continued Wednesday with easterlies moderate at Pass level and strong near ridgetops and above treeline. The strongest recorded winds were at Crystal mountain which saw gusts above 100 mph Wednesday morning.

Sunny weather continued Thursday and Friday with slightly warmer temperatures. Crest level winds shifted from moderate easterly Thursday morning to light to moderate westerly by Thursday evening, through Friday.    

Recent Observations

The New Year's champagne powder party was busted up this week as periods of strong to nuclear winds wreaked havoc on the snowscape in most areas.

East winds began to affect some areas by Monday and most areas by Tuesday. An NPS ranger at Paradise on Monday reported low visibility with significant snow transport to SW-W slopes. Shallow wind slabs were easily ski triggered on west aspects near treeline at White Pass Monday afternoon. 

A report on the NWAC observation page reported widely visible and ongoing transport occurring in the Stevens Pass area Wednesday due to east winds. 

We received a report of a skier triggered wind slab avalanche in the Crystal backcountry around midday Wednesday. A 15 cm (6") wind slab avalanche of pencil hardness broke 40-50 ft across and carried the skier 200 ft on a NW aspect in the upper portion of the below treeline band. The skier was not seriously injured, but lost equipment. NWAC is compiling more information on this incident and will be posting a report soon.

Additional field observations ranging from the Mt Baker area to Mt Rainier Thursday, highlighted the effects the recent strong E-NE winds have had on the snowpack. In general, the surface conditions in exposed terrain are a mixture and a mess, ranging from shallow to deep wind slabs of mostly hard firmness, sastrugi, scoured and wind sculpted surfaces and some soft snow.

In wind sheltered terrain and treed slopes, settling and stable powder conditions persist with some excellent skiing still available.

NWAC received tragic news late Thursday of an avalanche fatality in the Crystal Mountain south backcountry. The Crystal ski patrol came across the slide and debris and found the victim late Thursday morning. The avalanche likely released Wednesday. The victim was traveling solo. Members of the NWAC team were on-site Friday to assist with the investigation. A full report will be prepared and posted soon.