Avalanche forecast

Stevens Pass

Northwest Avalanche Center
View on map

Avalanche danger

Wed
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
3 · Considerable
Open full map
Out of date — this forecast expired 4 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

Use extra caution on the heels of a widespread avalanche cycle and very dangerous avalanche conditions. You can easily trigger avalanches on Tuesday and some of them could be very large and deadly.  Heavy rain, snow, and wind will continue through Monday night.

Avalanche problems

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    2–3

    Very dangerous conditions may remain above treeline. Avoid being on or under slopes 35 degrees and steeper. Stay well out from under large avalanche paths and runouts. Freshly built slabs could approach 6ft deep on leeward slopes and could break across entire start zones.

    We know that large to very large avalanches occurred on Monday and we expect another peak of avalanche activity Monday night. While natural avalanches should taper off by Tuesday, there's uncertainty about how easily you could trigger these very large avalanches. Manage the risk by minimizing your exposure to avalanche terrain. 

    Example very large natural avalanche from earlier in the season

     

  • Wet Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    2–3

    Wet avalanches could be very large and destructive. They may break widely on recent weak snow or crust/facet layers buried earlier in February. Avoid being on or under slopes 35 degrees and steeper where meltwater has reached weak layers and crusts in the upper snowpack. You may also be able to trigger loose wet avalanches on similar slopes. Rollerballs and other, recent wet slides are evidence that you could see more wet avalanches.

    Heavy rain will fall to 6,000ft through Monday night and should taper by dawn. Wet avalanche instability can linger after the precipitation has ended. Wet slabs are very difficult to predict. 

    Example of wet avalanches below Skyline lake on the west side of Stevens Pass from January 14th.

    Photo: Matt Primomo

Avalanche Discussion

Heavy snow, rain, and very dangerous conditions limited access and information on Monday. Over 4" of water equivalent fell between Sunday and Monday evening with rain at 5,000ft starting  WSDOT forecasters reported a widespread natural cycle of large to very large avalanches in the mid-morning as rain spread further east and into upper elevations. They also triggered a very large (D3) avalanche with explosives.

Observers noted very reactive conditions on Sunday, with storm slabs breaking about a foot deep, on the old snow interface. Many riders triggered slab avalanches that were in the small to large range (D1-2), and there was a close call with a rider buried to their neck on a NW aspect near Skyline. Some avalanches on south-facing slopes even triggered other pockets nearby (sympathetic). Stevens Pass Mountain Resort snow safety reported one slide that stepped down to a deeper crust layer. 

On Saturday, surface facets stayed intact before being buried even on south aspects. Beneath the recent snow, there are a number of crusts and potential weaker layers in the upper snowpack. The Valentines Crust serves as a prominent marker, as it's fairly thick in most places. On northerly aspects, it may be crumbly and mixed with facets, on southerly aspects its a stronger melt-freeze crust. 

Regions covered