Avalanche forecast

West Slopes Central

Northwest Avalanche Center
View on map

Avalanche danger

Wed
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low
Open full map
Out of date — this forecast expired 2 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

A mellow storm will drop varying amounts of new snow across West Central. Fall back to simpler, lower-angeled terrain if you see natural or human-triggered avalanches, widespread signs of instability, or simply more new or wind-drfited snow than anticipated. Wet avalanches could impact your travels if temperatures warm or the sun makes an appearance. Keep an eye on steep terrain overhead.

Avalanche problems

  • Storm Slabs

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

    The approaching storm isn’t really forecast to have “storm-worthy” snowfall amounts, but there are a few things that could increase the chance of seeing shallower slab avalanches.

    For one, areas with Puget Sound Convergence Zone enhanced snowfall could see higher snowfall rates and amounts. Also, a slight rise in freezing levels and temperatures could create a denser and more sensitive slab at the surface. Finally, sun breaks could increase slab reactivity in the afternoon. As usual, you are more likely to trigger a slab on slopes showing signs of active or recent wind loading.

    Pay attention to snowfall intensity throughout the day and track variations in snow depth as you gain elevation and change aspects. Evaluate the bond of new and wind-drifted snow layers before moving into avalanche terrain. Simple tests like slope cuts and hand shears can help you gauge slab reactivity.

    Cracking when adding weight above an existing track is a simple test you can use to look for the first signs of slab instability.

  • Loose Wet

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–1.5

    You could see small wet loose avalanches entraining new and maybe even older layers of snow on Tuesday. Increasing temperatures or sun breaks could provide the warming needed to make steep slopes shed snow.

    Monitor steep rocky or treed terrain overhead, especially if the sun comes out. Rollerballs and small wet loose avalanches are signs you could see more  - or bigger - avalanches. Use caution on steep slopes with wet, mushy snow, as you can likely get some snow moving with you down the hill if you push hard enough.

    (2/22/2024)

    Rollerballs are an initial sign that wet avalanches are more likely to occur as the snow surface warms.

    Photo: Dallas Glass

Avalanche Discussion

Chunks of cornice, pockets of snow clinging to steep rock, and glide avalanches are still things to look out for. These dangers are easy to identify and avoid as long as you are aware of what is directly overhead. Shedding snow can also trigger wet loose avalanches. 

Cloudy weather after a day of sun - combined with a case of the Mondays - limited the number of observations. Weather station data in West North showed gusty winds through the morning and near-freezing temperatures across much of the zone. The White Chuck Tripod - which is in a sheltered location to increase the accuracy of snow height measurements - was showing wind speeds from 3 to 5 mph which often means moderate winds in more exposed locations. Most areas of West Central picked up 0.1-0.3” of precipitation equaling a few inches of new snow and 2-5" of new snow was observed at mid-elevations in Snoqualmie Pass.

Wind slab formation is suspected but not confirmed at upper elevations. Areas farther east where dry snow was found above 4000’ may have seen more wind slab development and slightly higher danger at mid-elevations. Above-freezing temperatures might have kept wet avalanches in play in West Central and wet, sloppy snow was still found in Snoqualmie Pass. The snow surface stayed firm and supportable in Stevens Pass and one observer in West North reported the snow surface was generally “locked up.”

 

Regions covered