Avalanche forecast

East Slopes Central

Northwest Avalanche Center
View on map

Avalanche danger

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Out of date — this forecast expired 3 years ago.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

Highlights

If the avalanche forecast looks familiar, it's because the recurring weather pattern maintains another day of steady, light precipitation. Avalanches in wind-loaded terrain are becoming more stubborn to trigger. But if you are unlucky, you could trigger a large avalanche that breaks 2-3 feet deep. Choose sheltered terrain or steer around steep slopes with stiff wind-textured snow. 

Avalanche problems

  • Wind Slabs

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

    In some areas, stiff wind slabs formed over weak snow layers that take longer to strengthen, and you could still trigger a large, hard slab avalanche. These are becoming less likely with time, warmer daily temperatures, and cool nights. But a few inches of fresh snow and another bump in Southerly winds overnight maintain a possibility of triggering a wind slab. Winds have blown in multiple directions over the last few days, so look for wind slabs on various aspects or even mid-slope. Strong winds have pressed these slabs into firmer 1F-P hard slabs in exposed alpine terrain. Consider the high consequences of triggering a wind slab that breaks wider and deeper than expected if it fails on weak snow above the Early February Crust. 

    Use visual clues such as drifts around rocks or vegetation and textured surfaces to help you identify likely spots for wind slabs. Be suspect of terrain features, such as the leeward sides of ridgelines, alpine couloirs, gully features, and cross-loaded depressions. Dial it back if you notice shooting cracks, whumphs, or hollow-sounding snow. 

    (2/18/2024)

    Triggering a wind slab in the wrong spot could result in a much larger and wider avalanche if it breaks on old snow above the Early February Crust. 

    Forecasters observed this 1-2 day-old avalanche in the Teanaway drainage on Sunday. 

    W aspect, 6200 ft

    Photo: Katie Warren

Avalanche Discussion

Another day of very familiar weather is in store for Wednesday, and we'll wring out a few more inches of snow. These meager storms are slowly loading weak snow layers. This is particularly concerning in wind-drifted terrain, where slabs are much thicker and more dangerous. In many sheltered locations, there isn't enough slab structure to the snow for an avalanche. But the slab is getting deeper and more cohesive with continued precipitation and warmer temperatures. Anywhere you find more than 8 inches of snow above a stout crust or see wind-textured surfaces could be problematic. These slabs may not be that deep but could be large enough to ruin your day if they propagate widely on well-developed facets over a crust. You can use quick hand pits to observe the bond with underlying crusts. Avalanches are more likely if the snow slides easily as a cohesive block.

Lower elevations and southerly aspects have seen warming and sunshine. Both now have melt-freeze crusts of varying thickness on the surface. However, temperatures will notch up again on Wednesday, and you could see some wet loose avalanches or rollerballs a bit higher in the terrain than on Tuesday. 

The Wenatchee Mountains and other drainages in the southern reaches of the zone received 10-16" of recent snow. Initially, the new snow fell very cold and low density. However, recent warm temperatures are consolidating the surface snow to form a more cohesive slab. This slab may rest over weak, faceted grains or surface hoar associated with the Early February Crust (EFC) or a sun crust on southern aspects. This hasn't become a widespread problem yet, but we have quite a lot of uncertainty with the sensitivity and distribution of this avalanche problem. But, since February 15th, 13 unintentionally human-triggered avalanches have failed on or just above the EFC throughout the Washington Cascades. Most of these avalanches have been between 5000ft and 8000ft and cover all aspects. Thankfully, no one was injured in these incidents, but this is critical information that this weak layer can still produce avalanches. It is best to stick to sheltered terrain or low-angle, well-supported slopes while the weather keeps giving us windy conditions along with dribs and drabs of snow. 

On Sunday, we traveled into the Teanaway Drainage and found plentiful wind-affected surfaces and warming temperatures. We observed an old wind slab (W aspect, 6200 ft) that likely ran between the 15th and 17th of February and failed on weak facets on the Early February crust. This avalanche broke 3-4 deep and ran 300 ft. Lower elevations held little new snow, and warming temperatures may have developed a new melt-freeze crust on surfaces up to 6000ft in this area. 

Earlier in the weekend, a group of skiers near Ingalls Peak in the Teanaway had a close call and triggered a small soft slab in wind-drifted snow. The skier was able to arrest on the bed surface as the avalanche failed. This avalanche occurred on a south aspect at 5500 ft. You can check out the complete avalanche observation here. 

Your avalanche, snowpack, or weather observations are extremely valuable to the avalanche community. Help create a more accurate avalanche forecast by submitting your observations here. 

Regions covered