Bollettino valanghe

East Slopes South

Northwest Avalanche Center
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Pericolo valanghe

Thu
Alta quota
1 · Debole
Limite del bosco
1 · Debole
Sotto il limite
1 · Debole
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In sintesi

If enough sun and warmth hit a slope, then a small wet avalanche could release. Pay attention to the weather and retreat to shadier terrain if you and the snowpack are feeling hot and sticky.

Problemi valanghivi

  • Loose Wet

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Unlikely
    Dimensione
    1–1.5

    Warmer temperatures above 5000 ft, but slightly more cloud coverage by the afternoon, definitely make this one of those "if, then" problems. There are a few things working in your favor. At lower elevations, colder temperatures, low clouds/fog, and long mid-winter mountain shadows should control it. Wind from the east will help keep things cool as well. There may be a crust on the surface in many areas now that will need to break down first before the snow begins to soften. Clouds come in from both the west and south, so the sun will shine a little bit longer only on the northeast end of the zone.

    There is, however, a chance the sky will clear again later in the afternoon. Signs of weakening are snow surfaces becoming sticky, chunks of snow falling from trees, and fresh roller balls releasing on steep slopes. Pay attention to the terrain around you; weakened snow is more likely to release from steep cliffy terrain, and a small avalanche could knock you over onto cliffs and rocks. Give cornices a wider berth if you notice they're drooping. You can recreate earlier in the day or on shady slopes to avoid this problem entirely.

    (12/29/2025)

    Rollerballs of a steep sunny road cut on the Stevens Canyon Rd, Mt Rainier. This is one of the first signs of weakening.

    Photo: Andy Harrington

Avalanche Discussion

Forecasting this particular wet loose avalanche problem has proved quite tricky. Jumbled temperature inversions, varied cloud coverage, low sun angle, wind from the east, and minimal observations have left forecasters wondering where precisely this problem has occurred...or has yet to. It doesn't have to be tricky for you though. As long as you're mindful of the signs of instability, it will be very easy to avoid the problem. Don't be fooled by how chilly it will be at the trailhead; temperatures will warm as you gain elevation, even with some cloud coverage.

A NWAC forecaster traveled in the Nelson Ridge area near Bumping Lake last Saturday and found shallow coverage at lower elevations, but a more meaningful snowpack as they moved into more open slopes at middle elevations. They noted warming on sunny slopes, so after a few more days of high pressure, these areas likely have a surface crust now. At middle elevations, they found roughly three feet of snow with a favorable snowpack structure. There is a thin crust buried approximately 9 inches down that formed on Christmas Eve (12/24), a thicker crust buried deeper that formed on 12/18 and likely extends up into upper elevation terrain in some areas, and basal atmospheric-river crusts at the bottom of the snowpack.

They also noticed extensive wind affect, but did not find unstable wind slabs. They did not make it to upper elevations, so if you go poking around on higher, more complex slopes, it could be possible to find a lingering isolated wind slab. If you plan to recreate in this kind of terrain, take a good look for wind affected snow before diving in. You can check out the full observation here. 

Other than this one data point and telemetry data, we have no other snowpack information for the zone. Subtle changes in aspect, elevation, or canopy cover can significantly affect overall depth and riding conditions. Snowpack depths likely range widely across the East South. Expect a lean snowpack of roughly 20-30 inches in the eastern mountains and more robust 50-60 inches closer to the Cascade Crest. Where the snowpack is thin, downed trees, open creeks, and grabby bushes make getting to deeper snowpacks a challenge. Plan extra time into your day to navigate these obstacles.

You can help us out! Submit an observation on the avyapp or here.

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