Avalanche forecast

West Slopes Central

Northwest Avalanche Center
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Avalanche danger

Fri
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
3 · Considerable
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Highlights

Freezing levels are increasing to 10500ft in the afternoon so expect to encounter large, dangerous wet snow avalanches as the day progressively warms. We are unsure to what extent we will see wet snow avalanches, however, when you start noticing them coming down and increasing in size, shift your travels so that you are no longer in any steep avalanche paths or on the lower angle runouts beneath a path for the remainder of the day. This is a sudden shift after a large storm deposited about 2-3 feet of dry snow, and you could still trigger a lingering slab avalanche on wind-drifted steep slopes. 

Avalanche problems

  • Loose Wet

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1–2

    Temperatures will rapidly warm on Thursday, and you can expect to see a sharp increase in wet loose avalanche activity as the day progresses. A thin crust formed on southerly aspect Wednesday, but the intense additional warming of Thursday will quickly melt through that crust and affect the underlying layers. Two to three feet of otherwise relatively low-density storm snow will quickly lose strength and wet loose avalanches will begin running. They will first occur as small point releases originating on steep slopes by rocks, but they are expected to increase in size and distribution as the day continues to warm. We do not expect that they will entrain the entire depth of the new storm snow, however it is not out of the question if it heats up enough and large amounts are entrained. 

    A fair bit of uncertainty exists with the extent of wet loose avalanches Thursday. Avalanches may remain on south-facing slopes if it's mainly sunny, or they could wrap around the compass if cloud cover causes more even heating. If you're heading into the backcountry, prepare for the worst- large wet loose avalanches running on all steep slopes. Pay attention to snow surfaces from the start of the day. When snow gets wetter and stickier is when you need to pay even closer attention to nearby slopes and start thinking about a retreat.  If you start witnessing avalanches increasing in size and frequency, have a plan to quickly depart from avalanche terrain and avoid all avalanche terrain for the remainder of the day. This includes flat areas beneath steep slopes as well.

    (3/13/2022)

    Small wet loose, or point release, avalanches as the sun first moistened the dry snow in the Baker backcountry. Expect them to grow much larger on Thursday.

    Photo: Alyssa Young

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–2

    A large natural slab avalanche cycle occurred in the neighboring West North Zone during the storm on April 3-5. Layers will slowly stabilize and become less reactive. However, the quantity of new snow and size of avalanches we saw once the storm cleared warrants continued caution. You are most likely to trigger a slab avalanche on steep, wind-loaded slopes. Cornice fall or smaller wet loose avalanches could also act as a trigger for a large wind slab avalanche. This could possibly occur in a location where a human is not able to provide the necessary weight to trigger an avalanche.  A good example of this is an avalanche triggered in the Baker backcountry on Wednesday, where the 12th rider to hit a jump triggered a large avalanche upon landing. You can check out the well-written observation HERE.

    Search out locations of wind-drifted snow, identifying wind indicators such as wind lips or pillows, or textured surfaces. Strong winds during the last storm may have cross loaded terrain features so keep an eye out for unsual loading patterns. You're most likely to find drifts around features and rocky outcroppings, and in gullies. The drifts may be hard to identify, given the amount and distribution of snow. Avoid steep slopes where you find these features on Thursday. 

    (4/6/2022)

    A large avalanche which failed near the bottom of the storm snow, just above the summer road by Austin Pass in the Baker backcountry. The trigger was the 12th rider landing a jump in that location. We're glad no one was hurt and they provided a very helpful public observation to alert us to the event. 

    Photo: Public Obs

Avalanche Discussion

It didn't get quite as warm as we expected on Wednesday, and a breeze for most of the day kept surfaces cooler than we had anticipated. Early afternoon, a few rollerballs and small wet loose avalanches were reported in both the Baker backcountry and the Canyon Creek areas. There was less avalanche activity than we thought, but the change to significantly warmer temperatures forecasted for Thursday are alarming. Given the forecast, we suspect we'll see many more avalanches than we saw on Wednesday, warranting a rapid retreat from all avalanche terrain once avalanche activity begins.  Even if you're avoiding avalanche terrain and not getting into the steeps it's still a fine day spent out in the Cascades.

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