Avalanche forecast

East Slopes Central

Northwest Avalanche Center
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Avalanche danger

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

Morning Update: Less snow and wind than originally forecasted. The most likely places to trigger a large avalanche be above treeline, where you find blowing snow and recent wind slabs. Avoid steep slopes below ridges, the base of cliffs, and steep convex rolls where you find stiffer wind-drifted slabs of snow.

Avalanche problems

  • Wind Slabs

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

    Steer around areas of stiffer, drifted snow in steep open terrain at lower elevations. Avalanches could be bigger above treeline and easier to trigger. The best way to keep from triggering an avalanche is to avoid leeward slopes near and above treeline and stick to areas sheltered from the wind and slopes under 35 degrees.  Feel for stiff over soft snow layering and use inconsequential test slopes to identify and avoid areas of unstable wind-drifted snow.  You may find more recent, shallow slabs from east winds. Older wind slabs from west wind may be harder to trigger. Pay close attention to wind direction and blowing snow to identify dangerous leeward slopes. 

    (2/28/2023)

    A small wind-loaded test slope produced this mini wind slab. 

    Photo: Katie Warren

  • Loose Dry

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1

    You could trigger fast-moving dry loose avalanches in very steep, wind-sheltered terrain. These avalanches often start directly below your feet or as snow falls from trees and cliffs onto the slopes below. While they can often be easier to predict than slab, avoid being caught off guard in consequential terrain where you could be carried over cliffs or buried deeply in gullies. 

    (2/22/2023)

    An example of very small dry loose avalanches. 

    Photo: Katie Warren

Avalanche Discussion

There's uncertainty with this upslope, easterly storm, though snowfall has been downgraded this morning. On Friday, an observer in the Icicle Creek Drainage triggered a small slab on a steep convex roll that ran on this recent sun crust. There has been significant snow and winds over the last 3 days throughout the zone. Previously, the highest snow totals were near the Cascade crest where over 1.5 feet accumulated from March 2-4th.

As of Saturday, observers have reported that the recent snow is loose and uncohesive in most sheltered locations. On Southerly aspects, snow fell on a slick crust, which could be up to 1-2 feet deep near the Cascade Crest. While this potentially problematic layer may be isolated in distribution, it could produce avalanches as recent snow gains cohesion. At low-elevations and areas further east in the zone, this crust could be Sunday's new/old snow interface.You can find 1-2ft of recent snow sitting over a crust from Valentine's Day, which often presents as a crust/facet sandwich, with weaker snow beneath the upper crust. Observations indicate quite a wide variability in the structure of this layer. There has been a couple of isolated observations of instability on this layer in the Icicle drainage. We have yet to observe avalanche activity on this layer but continue to monitor it as snow adds up. If you get out into the mountains, submit an observation to share what you found.

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