Avalanche Forecast

Since the last warm rain event saturated the upper snowpack, cooler temperatures beginning over the weekend brought Hurricane Ridge 0.64” of snow water equivalent with a 3” snowpack increase from Sunday morning to Monday morning. The first inch of snow was blown around by moderate winds gusting strong to very strong early Sunday morning, forming some shallow wind slabs. Additional snowfall came at decreasing wind speeds and cooling temperatures and should be right side up in wind-protected areas, but wind slabs may be possible. The recent snow (estimated 5-8”) sits on a refreezing and supportable crust. 

A classic storm for the Olympics is moving in Monday afternoon with a lot of moisture hitting the south and west slopes and the models are struggling to figure out how much makes it to the lee slopes (model estimates currently range from 2-10”). Snowfall Monday night arrives on a warming trend, building heavier slabs on top of this lower density snow, an unstable snow structure, with a nice bed surface for producing avalanches that run farther than you expect. Winds should blow this snow enough to form large slabs in especially wind-loaded locations with a more widespread threat of storm slabs if we get more than 5” or more of fresh snow overnight (making a 10” storm slab above the crust). 

With uncertainty in the forecast snow water amounts and resultant distribution of avalanche problems, you’ll be wise to give the new snow time to settle anywhere your probe finds 6” or more above the crust. Watch for evidence of wind transport, such as freshly formed cornices or recently scoured ridgelines, and avoid the lee slopes below them where you can trigger a large and dangerous avalanche on Tuesday.

Forecast Schedule

For the 2019-20 winter season, avalanche danger ratings will be issued for the Olympics every Friday through Sunday and during mid-week holidays. During the week, No Rating will be issued but forecasts will include expected conditions and relevant travel advice.  If you are out in the Olympics, please share your backcountry observations with us.

Update: January 24th 2020 (The regional synopsis is updated every Thursday @ 6 pm)

During the afternoon of January 23, 2020 one person was buried and killed by an avalanche that released from the roof of a home north of Blewett Pass near Highway 97. The elevation was approximately 1,700ft above sea level. She was found underneath 4 to 5ft of debris. She was discovered and excavated some time after the accident, where CPR was performed. Additional emergency response arrived within 15 minutes, but they were unable to revive her.

Our deepest condolences go out to the family and friends of the victim.

January to Remember

A parade of storms since the New Year began brought relentless precipitation, and impressive snowpack growth throughout the region. Areas along the west slopes of the Cascades have rarely gone more than 24-48hrs without precipitation. In the past three weeks, the Volcanoes and Passes received 20-28in of water equivalent, translating into incredible snowfall totals - Mt. Baker Ski Area reported 240in of new snow since January 1. The majority of NWAC weather station sites are reporting snow depths well over 120% of normal for this time of year. Ongoing precipitation and fluctuating snow levels have maintained elevated avalanche danger throughout the month, with avalanche warnings issued for nearly all forecast zones on 4 separate days (January 6, 7, 12, 23).  

Snow depth imagery for the Northwest Region on January 23, 2020. Many areas in the Cascades and Olympics show well over 100 inches of snow on the ground. Image courtesy of NOHRSC Regional Snow Analysis. 

Location

January 1-23 Precipitation (Water Equivalent)

Hurricane Ridge

14.79”

Mt Baker Ski Area

28.65”

Harts Pass

11.2”

Stevens Pass

20.26”

Leavenworth

4.01”

Snoqualmie Pass

25.43”

Paradise, Mt Rainier

24.13”

Mt Hood Meadows

22.34”

Table 1: Precipitation totals for select weather stations January 1-23, 2020. Huge numbers at Baker, Rainier, Hood, and the Passes and there is still another week left this month.

MLK Weekend and a Pattern of Rain on Dry Snow

After a prolonged cold period with arctic air and lowland snow, MLK weekend brought unseasonably warm temperatures and a rapid thaw. High snow levels and rain caused wet avalanche activity throughout the region January 18-19. A few very large natural avalanches occurred at upper elevations where all precipitation fell as snow. A cooling trend followed, creating a pronounced crust that is now buried in almost all forecast zones. Cold, dry snow January 21-22 was followed by a rapid warm-up and the most significant rain on snow event yet, causing avalanche warnings on January 23 for 5 of our 10 forecast zones.

The crown of a very large avalanche around 10,000ft on the Newton Headwall of Mt Hood which likely occurred during the storm late last week. 01/19/20 Photo: Kevin Kayl

The buried MLK crust is widespread throughout the region and a prominent marker in the snowpack. Crystal Backcountry 01/20/20 Photo Jeremy Allyn

One More Week To Go

January isn’t over yet, and the long term forecast continues to show an active and wet weather pattern for the Northwest. The low-snow, drought-like conditions of the early season seem like a distant memory at this point. We’ve certainly made up for lost time in 2020, and this already impressive month looks to end with a bang.