Avalanche forecast

East Slopes North

Northwest Avalanche Center
View on map

Avalanche danger

Sat
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Out of date — this forecast expired 4 years ago.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

You can still trigger slab avalanches that formed with recent wind and snow near and above treeline. Use extra caution on slopes over 35 degrees where the wind has drifted snow into deeper slabs. You may see some small loose avalanches on steep slopes.

 

Avalanche problems

  • Wind Slabs

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

    You can avoid these avalanches by sticking to slopes that are less than 35 degrees and sheltered from the wind or scoured. Steer around obvious pillows and drifts and stay off of slopes with overhanging cornices. Look for wind features, cornices, and thick pillows of snow to indicate which slopes were loaded by the wind in the past couple of days. Use your probe to feel for stiffer, deeper drifts to indicate wind-loaded slopes. You can avoid triggering these avalanches by sticking to wind-sheltered or windward terrain, or traveling on slopes less than 35 degrees.  If you see recent avalanches or cracks shooting through the snow, seek these areas of safer terrain.

    (1/17/2023)

    An example of natural wind slab avalanches near the base of a cliff. 

    Photo: Katie Warren

Avalanche Discussion

On Friday, expect warming temperatures and sun. If the surface of steep sunny slopes becomes moist, you may see some small loose avalanches. Keep an eye out for rollerballs and moist surfaces as indicators. 

On Thursday, observers in the Silverstar and Varden creek drainages found test results indicating that the February 3rd interface is gaining strength and is becoming less of an issue for triggering avalanches. Earlier this week observers reported a number of large (up to size D3) avalanches throughout the Highway 20, Washington Pass area. Crowns were mostly below cliff bands or in other wind-loaded terrain. Many of these appear to have run during a 24-hour period on February 7th.

Almost 2 feet of snow accumulated from February 3-8th. Observers were able to trigger avalanches on the February 3rd interface just after the storm. On Wednesday, a triggered slide near the Lyal glacier stepped down to the new/old interface and broke into a large avalanche, 6,400ft, east aspect. On Sunday also near Rainy Lake, I found planar shear at the Feb 3rd interface at a profile site near treeline, though I couldn't produce similar results in a number of other quick tests near and below treeline.

There are a few layers that we've been tracking in the upper snowpack. Aside from the February 3rd interface, the Jan 5th surface hoar (about 2-3ft below the surface) had previously been widespread and problematic in snowpack tests. With time and rounding of the grains, this layer is likely gaining strength. At a profile on Sunday above Rainy Lake, test results indicated that the layer was not a problem for avalanches at that location. Elsewhere, especially in the eastern mountains, it could still be an issue if you cross a shallow part of a loaded slope.

Regions covered