Avalanche forecast

East Slopes South

Northwest Avalanche Center
View on map

Avalanche danger

Sat
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
3 · Considerable
Open full map
Out of date — this forecast expired 4 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

Triggering avalanches will remain likely, with the potential for very large avalanches running on the Christmas Crust. With this complex snowpack and overlapping problems, it will be best to avoid steep terrain and give large runout zones a wide berth. 

Avalanche problems

  • Storm Slabs

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

    Up to a foot of new snow with warming temperatures fell throughout the zone yesterday. Wet avalanches took center stage at lower elevations, while higher elevations remained as snow. The snow is beginning to taper off, but temperatures will stay quite warm. While natural avalanches are becoming less likely, you can still trigger a large avalanche anywhere you find a steep slope with dry snow. This new heavy storm snow sits on very low density snow, with the possibility of persistent weak layers lurking deeper in the snowpack. This upside-down snowpack will create sensitive storm slabs that are still reactive after the storm tapers, and avalanches may break wider than you anticipate. Make sure to avoid steep terrain and keep your terrain choices simple. Choose low angle slopes in denser forested areas and avoid common trigger points such as convex rolls or unsupported slopes. 

    (12/20/2022)

    Storm slabs like this may be easily triggered on Thursday. 

    Photo: Public Observation

  • Wet Slabs

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

    Wet slabs are notoriously hard to forecast. They sometimes release after peak precipitation, but temperatures are still warm. A layered snowpack with a thick crust from Christmas is a perfect setup for these destructive avalanches. They will be more likely Near Treeline and at upper elevations in Below Treeline terrain, where rain recently saturated 1-2 feet of dry snow. Avoid traveling on steep slopes where you may trigger one of these large avalanches. With this avalanche problem, you should also be very cautious of steep open terrain above you, as these avalanches may release naturally and run long distances.You will likely see smaller wet loose avalanches at lower elevations where less new snow rests on the Christmas Crust. 

    (12/23/2022)

    Example: Natural wet slab avalanche below treeline at Mt Rainier. NW 3800ft early in this storm cycle. Similar slides could still occur in the East South.

    Photo: NPS Rainier Rangers

Avalanche Discussion

On Wednesday, I traveled into the Soup Creek area. Most notably, I found deep pockets of wind-drifted snow and observed active wind transport along ridgelines. In some places, up to 3 feet of snow rests over the Christmas Crust. I traveled on multiple aspects and elevations around this zone and was able to locate buried surface hoar in sheltered areas on northerly aspects in meadows and sparsely treed slopes. This weak layer was typically buried 8-10 inches below the snow surface. After yesterday's storm, rain destroyed this layer, or snow buried it up to 3 feet deep. The neighboring east-central zone reported numerous human-triggered avalanches on these weak layers in the past week, including very large wet avalanches on Thursday. So as this warm weather continues, it is essential to know that this is a complex and dangerous snowpack that is still adjusting to a significant new load. With limited observations since last night's storm, we are unsure what locations have avalanched and what slopes may be waiting for the right trigger. Give the snowpack time to adjust to this large load and cooling temperatures to help freeze the soggy wet snow before stepping out onto steep slopes. 

Regions covered