Avalanche forecast

Stevens Pass

Northwest Avalanche Center
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Avalanche danger

Mon
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
2 · Moderate
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Highlights

The spring shed is on, and conditions are becoming dangerous in the mountains! A multi-day warming trend will peak on Sunday with temperatures rising into the 50's at 5,000ft. Large wet avalanches and cornices are expected to fall as the daytime warms up. Finish your day early, and avoid going on, or underneath steep slopes that are in direct sun. 

Avalanche problems

  • Cornices

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    2

    With the very warm temperatures, cornices may begin to sag, and fall. Some of these cornices are very large, and could be dangerous in their own right. Large cornices could also impact slopes below and entrain into even larger avalanches. With the very warm temperatures, snow has also been shedding from rocks.

    As a general rule, try to avoid large, complex terrain features that could harbor cornices and rocky cliffs with snow pillows. Consider what is beneath some slopes with large cornices, and steer clear from their runout zones. 

    Drooping cornice on Lichtenberg from late January. It is slowly peeling away from the ridge, and is much larger now.

    Photo: Matt Primomo

  • Loose Wet

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1.5–2

    Wet loose avalanche activity is expected to increase in frequency and size on Sunday. A weak overnight freeze should quickly break down as soon as the slopes receive sun. As with the past few days, avalanche danger will be lowest in the early morning, but then will quickly rise to Considerable with daytime warming. The day shouldn't be nearly as friendly as the past few were, and it'll be essential to start early and avoid slopes in the sun. Pay attention to how supportable the surface is, looking for wet, punchy snow, rollerballs, and wet avalanche activity. Be ready to finish early, and avoid traveling on, or underneath large steep slopes in the sun.

    Loose wet avalanches could become large in larger terrain features at mid and upper elevations. In these places they may also become larger by gouging into deeper layers. Even a small wet loose avalanche could be consequential if it knocks you off your feet and carries you into trees, rocks, over cliffs, or buries you in confined terrain.

    There's also potential for wet slabs on Sunday. These are most likely on steep, rocky and unsupported slopes that receive direct sun, and could be triggered by rollers or loose wet sluffs. The best advice is to move away from steep slopes before the snowpack becomes punchy and unsupportable. 

Avalanche Discussion

Sunday is expected to be the warmest day in quite some time. Temperatures should climb quickly first thing in the morning and reach the 50's at around 5,000ft. This tends to be a critical temperature for snow...so the mountains should continue to shed, and at an increased rate. Snow surfaces should freeze overnight, but the freeze probably won't hold up long. A slight bump in winds ahead of the next front could make for a breezy day at the highest elevations. Observers reported that south slopes became wet and saturated by around 1pm. An isolated pocket of a windslab was triggered with a shooting crack nearby at the top of the Swath (see photo below). Here, some dry snow still exists. Recent wet loose avalanches were observed in areas such as the west face of Arrowhead and south slopes of Lichtenberg as well(see photos below).

Most slopes hold a mix of crusts and moist snow. Directly north facing aspects above treeline may still hold dry snow and east to north to west aspects are still undergoing a transition from a winter-like snowpack. Last week, Stevens Pass picked up about a foot or more of new snow that mostly trickled in over a number of days. Observers reported that avalanches were easy to trigger on Tuesday, and some ran naturally. Observers also triggered small slab avalanches on leeward slopes beneath wind drifted features that day. 

This is NWAC’s last daily avalanche forecast for the 2021-2022 winter season. Mt Weather Forecasts will continue until May 1. Make sure to check our Spring Avalanche Statement for information and travel advice. NWAC will continue to track snow and weather conditions. Large storms and/or widespread avalanche cycles may cause us to issue special avalanche bulletins, avalanche warnings, or other spring statements to keep you informed. You can help your backcountry community by continuing to submit observations of avalanches, snow, and pertinent weather to our site. Have a fun and safe spring recreating in the mountains!

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