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Out of date — this forecast expired 5 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

Deep persistent slabs are unlikely, but not impossible. Unstable areas of shallow wind slab may still be found on high elevation, shaded slopes. These hazards are most likely in very steep, and unsupported terrain in the shade.

Avalanche problems

  • Deep Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely
    Size
    3

    Observers continue to find sudden results with snowpack tests on a layer of faceted grains above or within the Mid-January Crust. Deep avalanches have been 3-8ft deep, and the crowns generally encompass most if not all of the terrain feature. Higher elevation shaded, and heavily wind loaded, or unsupported slopes may be the most likely areas one of these could still happen. Steep slopes that face the sun may have a thick melt-freeze crust near the surface. If this is the case, these may not be a concern on those slopes. 

    Be intentional about where and how you travel, and be sure to discuss the low probability but high consequences with your partners. Before venturing into or under big terrain features, ask yourself, what would a very large avalanche in this terrain look like? How far could it travel?

    Cornices are large and sagging in some areas, keep on the lookout for these and stay well away from them. If cornices fall, they could trigger very large deep persistent slab avalanches.

    (3/3/2021) This avalanche likely occurred around February 26. ENE aspect at 7,300ft west of Cashmere Mountain.

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely
    Size
    1

    Shallow wind slabs were created up until Monday the 1st in higher elevation alpine terrain. These slabs are becoming harder to trigger with time. Still, it wouldn't be impossible to trigger a firm, shallow slab on high, shaded slopes on Wednesday. Be especially careful around unsupported slopes and in consequential terrain. 

    If there are sun breaks during the day, keep an eye out for moist, sticky snow and rollerballs. These are all good indicators that you could initiate small wet loose slides on steep slopes of similar aspects.

    (3/8/2021) Wind textured snow with a recent, shallow wind slab in alpine terrain of White Pine Cirque. Northeast aspect at about 6,400ft.

Avalanche Discussion

We don't have any new observations of deep slab avalanches since March 1, however the snowpack structure needed to make them can still be found in many areas. We currently have a wide range of conditions between mountains near the Cascade Crest and further east. The slab that sits over this weak layer ranges dramatically from around 8ft thick near the crest to less than 3ft in the eastern Wenatchee Mountains. We've pulled the Deep Persistent Slab problem from other zones in the Central Cascades, but there is just too much variability and not enough confidence to do that in the very large East Central Zone.

A cool, showery regime has recently set up, so you may find an inch or two of fresh snow over older surfaces. Expect variable, wind-textured snow and melt-freeze crust beneath an inch or two of fresh snow. Observers found reactive wind slabs 6-8" deep in the Wenatchee Mountains on Monday. Plenty of wind-textured snow could be seen in alpine terrain east of Stevens Pass from a distance as well. The last major storm cycle occurred February 25-26th with ~2" of water equivalent at the Cascade Crest and extreme winds. This came on the heels of a very large storm that brought up to 6" of water equivalent to the mountains near the crest but much less to the Wenatchee Range further east. Numerous deep and very wide avalanches (Many D3-3.5's, some size D4's)  ran between February 21st and March 1st in the mountains near the crest, and some deeper slabs were reported from the Wenatchee Range. In the northern end of the zone, near Holden, the mid-January weak layer doesn't appear to be a concern anymore.

Regions covered