Avalanche forecast

West Slopes North

Northwest Avalanche Center
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Avalanche danger

Sat
Alpine
3 · Considerable
Treeline
2 · Moderate
Below
1 · Low
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Highlights

Anticipate a sharp rise in avalanche danger as a fast-moving, windy storm whips through the region. Sheltered, lower-angle terrain should offer some refuge from heavy snowfall and strong winds.  You are more likely to trigger or get caught in an avalanche during or immediately after a storm. 

Avalanche problems

  • Storm Slabs

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

    Snowfall amounts for the coming storm are not exceptional, but other factors could increase the likelihood of triggering an avalanche. You could see snowfall rates of over 1” per hour in the morning. Fresh slabs are more reactive when this much snow comes down this quickly. 

    It's more likely you'll trigger an avalanche on slopes where strong winds build thicker, more sensitive slabs. There should be less wind transport at lower elevations, but assume the danger is higher if you find wind-transported snow in typically sheltered areas.  With a variety of old snow surfaces out there, you could still find shallow avalanches in wind-sheltered terrain holding more than a few inches of new snow.

    Stormy conditions should keep you off big open slopes. You can use simple tests like hand shears, test slopes, and tilt tests to evaluate the bond of new snow layers. Whatever you find, the best bet would be to stick to low-angle, sheltered terrain while the storm plays out.

    Stormy weather makes it harder to assess instability in open terrain.

Avalanche Discussion

Reports of crusty conditions and challenging travel seem to have kept folks out of the mountains and limited observations over the past few days. One team traveled high up on the north side of Baker on Thursday and found a variety of snow conditions. While there was plenty of crust and rime, there were also slopes that held softer snow. No wind slab was found and warming on southerly aspects in nearby terrain wasn't enough to produce fresh wet avalanches. High clouds kept the sun in check for most of the day

A combination of mild temperatures and sun formed crust that now tops the snowpack pretty much everywhere. It's found on most aspects and low and mid elevations, and slopes facing the sun at upper elevations. A trace to a few inches of new snow didn’t do much to improve riding conditions but may have faceted and become weak. Surface hoar was also reported in other forecast zones along the west side of the Cascades. 

The wide variety of surface conditions means there could be a wide variety of avalanche activity, even between slopes with similar characteristics.  This is a good setup to see more reactivity at the old-new snow interface than usual. Take the time to assess the bond of the old-new snow interface through the weekend before stepping into steeper terrain. 

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