Avalanche forecast

Stevens Pass

Northwest Avalanche Center
View on map

Avalanche danger

Mon
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
2 · Moderate
Open full map
Out of date — this forecast expired 3 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

Expect another very cold day, but at least the sun should make an appearance. You'll find variable wind-affected surfaces on open slopes at all elevations; some may hold reactive wind slabs. Look for signs of instability like shooting cracks or whumphing collapses, and identify steep slopes to avoid that may hold similar conditions. 

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–2.5

    Easterly winds blew through the pass Friday night through Saturday. The low density snow was easily drifted into reactive slabs in exposed areas. Identify large, open, and steep slopes where thick drifts of snow may exist. Avalanches should be easiest to trigger on leeward and cross-loaded slopes at mid and upper elevations, and in slabs that are recently formed. Look for surface textures and feel for stiffer snow as you travel to get an idea of steeper areas you may want to steer around.

    You can still find drifted slabs from northwest winds that formed as recently as the night of the 11th. If you receive any "red flag" signs of instability like whumpfing collapses or recent large avalanches, stick to low-angle terrain. The 4-6ft of recent storm snow is resting on crusts and weaker snow buried in late December. While triggering one of these monsters is unlikely, some potential still exists for the time being. 

    (1/10/2024)

    Stevens Pass patrol triggered a hard slab avalanche with explosives on a heavily wind-loaded slope.  Stevens Pass Resort, NE, 5,000ft. D2.5, 190cm deep

    Photo: Stevens Patrol

Avalanche Discussion

Saturday was the coldest day of the season so far, and I wouldn't be surprised if it remains so to the end. Temperatures hit -20 at Tye Mill, -17 at Brooks and Grace Lakes, and -12 at Schmidt, Brrrr!!  A multi-agency forecaster team in the clear cut zone of Henry Creek found lots of wind affected snow surfaces from the active east winds. They found some stiff wind board-like snow surfaces mixed in with softer areas. They observed wind drifting at all elevations up to the ridgetop on Rock Mountain. Only minor instabilities with the drifted snow were found, but they did get fairly long one shooting crack. They could see a large avalanche from one of the Camp Chutes west of Berne on the south side of Rock Mountain. It stopped in the track and was estimated to have run on the 11th with heavy snowfall and strong winds. 

Because of the poor visibility most of the week, we have a limited understanding of the avalanche cycles that occurred between January 8 and 11th. We do know that natural avalanches occurred on the 11th, possibly on the 9th, and a widespread natural cycle occurred on the night of the 8th. During this period the zone picked up around 5 feet of snow, with strong to extreme winds at times. Many avalanches that occurred are likely long buried by more recent snow and wind drifting. Stevens Pass Patrol and WSDOT reported many avalanches triggered by ski cuts and explosives. Most were size D1.5 or smaller, running within the recent storm snow. A few explosive-triggered slides were deeper and ran in layers of older snow (Solstice crust). On the 10th, ski patrol triggered a notably deep (190cm or 6 feet!) size D2.5 slab avalanche on a heavily wind-loaded terrain feature. On the 6th, a skier was carried in an avalanche on Valhalla Peak that likely ran on a crust from December 30th. 

If you venture into the eastern edge of the zone, be sure to check out the East Central forecast, as persistent weak layers may be more prevalent there. The East Central zone is more plagued by persistent slab avalanches on a similar but shallower snowpack structure. On the 10th, a skier remotely triggered a persistent slab avalanche on Dirty Face Mountain, just over the border. The Solstice crust is now about 4 feet below the surface in the Stevens Pass zone. Snow profiles below show some of these deeper crusts and weak layers, along with some sudden test results. 

Regions covered