Avalanche forecast

East Slopes Central

Northwest Avalanche Center
View on map

Avalanche danger

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Out of date — this forecast expired 3 years ago.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

Highlights

Another sunny, warm afternoon is in store for Saturday afternoon, with the potential for a poor overnight refreeze of snow surfaces. Wet avalanches will be possible by the afternoon and more likely on sunny slopes. Move off of steep terrain where the snow feels wet and heavy. With spring warmups, the potential for cornice falls and surprising avalanches is possible, so consider this additional uncertainty when choosing terrain. 

Avalanche problems

  • Loose Wet

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

    Temperatures will notch up again tomorrow, and cloud cover overnight may limit the extent of an overnight refreeze. Morning clouds will give way to clear skies, and the strong March sun will make the snow surface wet and heavy on sunny slopes. Recent sunny days and cold nights mean that the sun will have to melt recently formed crusts before wet loose avalanches really start to move. Still, by Saturday afternoon, these wet loose avalanches are likely to be larger and easier to trigger than on Friday. Wet loose avalanches tend to start from a single point and fan out, entraining more snow as they move downhill. Steep cliffs, rocky terrain, and tree bombs often initiate these slides, but you can also trigger them by skiing in steep terrain. Rollerballs, pinwheels, and sticky snow are all signs that the likelihood of wet loose avalanches is increasing. With temperatures potentially climbing into the upper 30s (°F) at lower elevations, you could even see wet snow begin to slide on shady slopes. These avalanches may be more predictable than slab avalanches, but they carry a lot of mass and can push you into terrain traps or over cliffs. Steep rock faces could release as wet slabs or glide avalanches and be quite large. These slides can be very unpredictable, so be aware of the overhead hazards from steep rocky terrain heating up in the sun.Along with wet loose avalanches, large cornices may begin to fail with the warming temperatures. When they fail, these large overhanging blocks of snow are hazards on their own but pack enough weight that they could also trigger slab avalanches on the slopes below. There is a possibility that avalanches triggered by large cornices could be very large and carry fatal consequences, so best to avoid lingering under these overhead hazards. 

    Consider moving to shadier slopes if you notice signs like this.

    Photo: Joe Dellaporta

  • Wind Slabs

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

    It's been a few days since significant snowfall, but the winds have been active, and there are likely lingering pockets of wind slabs at upper elevations. You will most likely trigger one of these avalanches in very steep alpine terrain on lee slopes. Use visual clues such as textures surfaces, drifts around trees and rocks, and cornice formations to identify wind-loaded slopes. Steep ridgelines, the base of cliffs, and confined gullies and rocky couloirs are likely locations to trigger a wind slab. Steer around these deep-looking drifts where you find them in steep terrain. Shooting cracks and hollow-sounding snow are also sure signs to avoid wind-loaded features. While unlikely, avalanches above treeline could break deeper and wider than you may anticipate. Last week's loading event resulted in a couple of very large, natural avalanches above treeline (see photo and discussion below for more details). 

    (3/11/2023)

    Crown of a very large avalanche in the Icicle Creek Drainage. We have a lot of uncertainty surrounding this avalanche problem. But best to make conservative choices in alpine terrain.

    Photo: Matt Primomo

Avalanche Discussion

We have been in a stormy period for the last couple of weeks, and now that the sun is out and temperatures are creeping higher, we are beginning to see an initial spring shed cycle occurring throughout the Cascades. Very large natural and human-triggered avalanches have occurred over the last week. There isn't a consistent failure layer from zone to zone for these avalanches. But with continued warming, the pattern suggests a continuation of this trend for large and hard-to-predict avalanches throughout the weekend. As we ease into spring, take a conservative mindset for this transitional period to account for the uncertainty surrounding these larger slides. The time may not be right for larger and more complex objectives quite yet. 

The recent snow has piled deep over a couple of intermittent sun crusts and a pair of rain crusts from Valentine's Day, which are around 3-5ft deep. This crust extends to just below 7000ft with some weaker snow beneath it, and observations indicate wide variability in the structure and depth of this layer throughout the zone. The MLK crust is down 4-6ft and extends to higher elevations. Very large avalanches that occurred on the 10th on Cannon Mountain and Rock Mountain may have run on one of these crusts or some other deep layer, but we cannot say for sure.  

Regions covered