Avalanche forecast

West Slopes North

Northwest Avalanche Center
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Avalanche danger

Sat
Alpine
3 · Considerable
Treeline
2 · Moderate
Below
2 · Moderate
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Out of date — this forecast expired 8 months ago. You’re viewing past conditions, not the current bulletin.

Highlights

Avoid steep slopes where you identify signs of recent wind-drifted snow, such as rippled surfaces, rounded drifts, or stiff, slabby-feeling snow. Warming temperatures and possible sun breaks could increase the likelihood of both slab and loose snow avalanches. Take time to assess the snowpack before committing to larger terrain. Pay attention to changing conditions.

Avalanche problems

  • Wind Slabs

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

    You may find little to no sign of wind effect in some parts of the forecast zone on Friday, but wind slabs become more likely the farther west you travel. Let signs of recent wind transport—scoured ridgelines, fresh cornices, or recent avalanches—drive your terrain choices. Track changes in snow stiffness as you move across aspects or gain elevation, and gather information about upper snowpack layering before committing to steep, wind-exposed terrain.

    (12/29/2021)

    Example of a small wind-affected feature showing both wind scouring and loading in close proximity.

     

  • Storm Slabs

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

    Warming temperatures may allow a stiffer surface slab to form over colder, lighter snow below, increasing slab reactivity. They should generally be small and shallow, but larger, older slabs may still lurk on very steep, unsupported slopes.

    Use test slopes and simple observations to assess how well the new snow is bonding before committing to bigger terrain. Shooting cracks, whumphing, and recent avalanche activity are red flags. When in doubt, choose a lower-angled option and avoid slopes with terrain traps in the runout below.

    (1/1/2023)

    Slabs on steep slopes getting primed by a bit of sun or warming are where you could find one of these on Friday.

    Photo: Jeff Hambleton

Avalanche Discussion

Uncertainty runs a bit deep in Friday’s avalanche forecast. There are signs the snowpack is trending toward better stability as recent storm and wind slab layers settle and gain strength. Only a few new avalanches were reported from areas that saw extensive activity earlier in the previous days, and snowpit tests are producing insignificant results. But there are some question marks that will probably only get answered once you are out in the mountains.

The biggest unknown is variability in wind loading. Some areas appear to have seen little to no recent transport, while others show signs of wind-affected snow and lingering sensitivity. Rising temperatures could also increase slab reactivity, especially if soft surface snow stiffens into a slab over colder snow below. Cloud cover should limit solar input, but any extended sun breaks on southerly aspects could produce loose snow avalanches, given the amount of low-density snow available.

Recent avalanche activity adds another layer of uncertainty. While many avalanches from this cycle resembled typical new-snow and wind slabs, a few larger slabs with wide crowns were observed in mid-slope terrain. No buried surface hoar or persistent weak layers have been confirmed; however, short spells of clear sky between recent storms leave open the possibility that thin weak layers formed and were quickly buried in a very spotty and inconsistent manner.

Anticipated conditions on Friday don’t point to a single, simple message. Instead, they demand attention to detail—where the wind blew, how the snow feels underfoot, what the sky is doing, whether it's getting warmer, and if recent avalanche activity lines up with what you expect to see. Good observations and terrain choice will, as always, be the best way to manage uncertainty.

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