Avalanche forecast

East Slopes Central

Northwest Avalanche Center
View on map

Avalanche danger

Thu
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
3 · Considerable
Open full map
Out of date — this forecast expired 5 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

On Wednesday, very warm temperatures and rain to the highest elevations could be the tipping point into another avalanche cycle. You can easily trigger wet avalanches in steep terrain, and very large avalanches are also possible in certain areas. Avoid travel in large alpine terrain and exposure from slopes above and avoid steep terrain features at lower elevations.

Avalanche problems

  • Loose Wet

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

    The temperatures will be continuing to ramp up overnight on Tuesday, and snow levels could hit a high of 8000ft by Wednesday morning and soar even higher Wednesday night. Tonight and tomorrow may be the first time upper elevations see above freezing temperatures on the East side of the Cascades.  You can easily trigger these wet avalanches if you manage to access the upper elevation terrain. Avoid traveling on steep terrain features or under cornices or cliffs where falling snow and cornice chunks may initiate wet loose avalanches. 

    At lower elevations, a surface crust formed on January 7th may be broken down by above freezing temperatures overnight on Tuesday. Dry snow still exists beneath this crust, and you will be able to trigger wet loose avalanches on steep terrain features as rain infiltrates the snowpack. If you notice glopping and heavy, wet snow over dry snow surfaces, it's time to get off steep slopes. Wet snow problems change the snowpack rapidly and develop instability in minutes.

    This warm-up will likely bring down the rest of the roof avalanches, so use caution and make sure children and pets stay well out from impact zones.

    (1/8/2022)

    Multiple avalanches, with recent loose wet slides off steep rocky features in the lower Icicle.

    Photo: Matt Primomo

  • Deep Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    2–3.5

    Significant warming and rain will continue to test a thick slab that overlies weak layers formed by a decomposed crust from the Solstice, among other deeply buried weak layers. You can trigger very large, deep slab avalanches as you are approaching steep slopes, so give them a wide berth.

    As this warm wet storm impacts the Cascades Tuesday night and Wednesday, the likelihood of triggering these deadly slabs increases. Rain infiltrating the snowpack could also initiate another round of avalanches on these deeply buried weak layers. While less rain is in the forecast for the eastern part of the zone where this problem is more prominent, these very large avalanches could run naturally if we get more rain than forecast. Therefore, it will be imperative to avoid being in or under terrain that could produce them. Stay out from under any large, open alpine terrain. Currently, the western portions of this zone have not shown deep persistent slabs to be as prevalent, but significantly more rain towards the Cascade Crest could be the tipping point. If these deep persistent slabs occur near the Cascade crest, they may be wet and very destructive.  

    In the open foothills, avalanches may be easier to initiate. Stay off of steep slopes if they have not avalanched yet. Northerly aspects with recent wind loading are the most likely places to trigger these. 

    (1/10/2022)

    Deep slab- ENE Facing at around 5,400ft off Pt 5510 above Iron Creek, near Blewett Pass. (Estimated: HS-N-R2-D2.5-O).

    Photo: Matt Primomo

Avalanche Discussion

Wednesday's will bring the highest freezing levels yet this winter, and upper elevations will likely see rain for the first time. The snowpack remains highly susceptible to more loading and a significant warm-up after weeks of cold temperatures. Lower elevations where crusts formed at the end of the last storm cycle may break down with sustained above freezing temperatures. This crust may never have formed above 6000ft and in the northern and eastern portions of this zone. Very large avalanches are still being reported, and snowpack conditions are variable, with a vast difference between the eastern and western portions of the zone. These factors, along with limited observations, introduce a lot of uncertainty to our forecast. It will be best to let the mountains adjust to another round of weather before venturing into steep terrain or higher elevations. 

This system comes just days after the East Central zone received a record-breaking storm January 5-7, where many areas, including towns, picked up 3-4ft of new snow. Many large and very large avalanches occurred as recently as Saturday. Control at Mission Ridge pulled out a 3'-5' deep hard slab on the Solstice Crust, and 5' deep hangfire was also easily triggered. Backcountry travelers over the weekend reported touchy conditions and isolated whumphing near Mission Ridge on Saturday. Debris piles were visible in many of the lower Tumwater and Icicle Creek drainages. Some of these avalanches were very large, carried trees with them, and one came within a few hundred feet of some houses. 

On Thursday morning, a D2.5 slab avalanche damaged a house south of Entiat (SS-N-R3-D2.5-O). The front door and garage doors were damaged, and the slide buried a car in the driveway. The slide likely ran on depth hoar on the ground (see photos below). Observers documented many different weak layers in the zone before the storm. The recent layers were large stellars, facets, and surface hoar from 1/2 and 12/29. A decomposing crust from the Solstice was the bed surface for some slides at Mission Ridge. An even deeper crust from Early December showed propagation potential on high elevation, shaded slopes in the Icicle drainage. At this point, these layers could be from 3-8ft deep and act as the weak layer for slab avalanches.

Many great Observations have come in from the area. Thanks, and keep them coming as we unravel the saga of last week's storm and move into this current storm and avalanche cycle.

 

Regions covered