Avalanche forecast

West Slopes North

Northwest Avalanche Center
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Avalanche danger

Sun
Alpine
3 · Considerable
Treeline
2 · Moderate
Below
1 · Low
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Out of date — this forecast expired 4 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

Today is the first day of the 2022-2023 forecast season! Avalanche danger increases as you gain elevation, where more precipitation fell as snow rather than rain in the past day. Identify thick, wind-drifted pillows of snow, and steer around these locations on steep slopes.  Pay attention to conditions as they may evolve throughout the day, with increased wind and snow developing in the afternoon.

Avalanche problems

  • Wind Slabs

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

    It is likely that you could trigger an avalanche in areas where wind deposits fresh snow into thicker drifts. Upper elevation slopes received up to a foot of snow on Friday. The transition from minimal low-density new snow to a much thicker coating may happen quickly, so be sure to pay attention to the snow beneath you as you gain elevation. 

    Wind is forecasted to increase in the afternoon, and as snow redistributes into new slabs, it may become even easier for you to trigger a wind slab avalanche. Later in the afternoon, our next period of precipitation begins. Especially as the storm picks up intensity, the danger may elevate even more. Continue paying attention to changes as the day progresses, and shift to lower angle terrain or non-wind loaded slopes if you identify deep wind-loaded drifts of snow, or identify obvious clues of instability such as long, shooting cracks or whumphing.

     

     

     

    A small wind slab avalanche triggered by a skier on a steep rollover last year.

    Photo: Greyson Herdman

Avalanche Discussion

Rain lines slowly dropped on Friday Nov 25, and Heather Meadows recorded 4 inches of snow in the waning hours of the storm accompanied by one inch of water. Leading up to this week, we had 2-3 feet of snow on the ground at mid to upper elevations. This snow sat under high pressure from Nov 8 - Nov 21. Weak, faceted crystals formed in shady areas. Meanwhile, hard, sun-affected surfaces developed on south-facing slopes. Upper elevation treeless terrain was buffeted with wind from all directions, so fewer pockets of weak snow developed on shady aspects here.  

Almost 3 inches of rain fell Nov 22, destroying most of our weak snow concerns. Many surfaces are now capped with a crust from that rain event, although above approximately 5500ft enough rain may not have fallen to destroy any weak layer which managed to persist despite the wind. In these upper areas, beneath 1-3 feet of snow, there may be a few isolated pockets of weak snow. You are probably more likely to find this when you get closer to the divide. Information is limited in general at this time, however we know even less about conditions at higher elevations. Please share with us how your trip went if you get out on Saturday by submitting an observation. 

Snow cover is thin this time of year, especially in near and below treeline areas. Travel carefully to avoid hitting stumps or rocks, or falling in an open creek. Snow conditions are extremely variable depending on elevation. We’ll be seeing more snow coming in Saturday night and in the meantime, have a great start to the winter!

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