Avalanche forecast

West Slopes North

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Out of date — this forecast expired 4 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

A final day of warm temperatures will round out a week of wet avalanche activity and poor snow conditions. You can find wet avalanches on all aspects with higher danger on sun-exposed slopes. Reduce your exposure to steep terrain overhead, especially below cornices and glide cracks.   

Avalanche problems

  • Glide Cracks

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1.5–2.5

    Tuesday will be the last day of high freezing levels before a cooling trend takes over the second half of the week. With clear skies in the forecast, there should be an uptick in natural avalanche activity as solar radiation increases melting. This will further weaken cornices and slabs of snow still clinging to steep rocky areas. [Glide avalanches occur when the entire snowpack is lubricated by water and slides on a smooth ground surface like a rock slab]. Wet loose avalanches - natural and human triggered - should be on your radar as well. Reduce risk by minimizing travel on or under very steep slopes, cornices, and glide cracks. There is a greater chance of seeing avalanches in terrain receiving strong sun - but anywhere the snow surface is wet and unsupportable requires caution. 

    (3/25/2022)

    Glide avalanches on south-facing slopes near Cascade Pass. These likely released early last week with the initial warm-up and rainfall.

    Photo: Mark Allen

  • Deep Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely
    Size
    3

    A deeply buried layer of faceted snow is suspected to be the underlying cause of very large avalanches that occurred the past two weeks. This post from photographer and pilot John Scurlock perfectly illustrates the deep persistent slab avalanches seen as of late -  a big, deep, and dangerous avalanche, triggered by cornice fall from above, on a northerly slope above treeline. It’s quite unlikely a single person could trigger one of these avalanches, but they continue to occur with a big loads like cornice fall or a wet snow avalanche from above. A return to high freezing levels means more cornices or wet loose can fall down and provoke one of these monsters. Like the wet avalanche problems listed above the best you can do is stay out of the way.

    (3/27/2022)

    Large (D3) avalanche on the western lobe of the White Salmon Glacier suspected of releasing in the March 8th faceted layer. Time and date of occurrence unknown.

     

Avalanche Discussion

In the last week, observers reported dry snow conditions and wind slabs in alpine terrain above 6000'. Look for freshly wind loaded features and shallow slabs anywhere it’s cold enough for dry snow to accumulate. Track the depth of new snow as you gain elevation or change aspects. Evaluate the bond of new snow layers before getting into steep terrain with consequences.

Temperatures at 5000' have been above freezing for the last week aside from a few spells in the high 20's. Partly cloudy skies overnight into early Tuesday could form a melt-freeze crust at the surface, even with above freezing temperatures. Though the crust could improve travel conditions and maybe even make for a quasi corn cycle, don’t expect it to last for long. 

From March 13th to 21st Heather Meadows received steady precipitation at near freezing temperatures. Though some fell as rain most came as snow with over 5' of new snow recorded. In addition to storm and wind slab avalanches, three very large slab avalanches were reported on March 16th- two natural and one from avalanche control work. All three were suspected of releasing in the layer of facets buried on March 8th. On the 21st a rapid rise in freezing levels and periods of rainfall laid waste to the powder bounty with wet, gloppy snow conditions and wet loose avalanche activity reaching well into the alpine. Warm temperatures - along with periods of rain - dominated the weather pattern in the last week.

Regions covered