Avalanche forecast

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Northwest Avalanche Center
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Avalanche danger

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

Natural or human-triggered wet snow avalanches are more likely in the western, wetter parts of the zone, while the likelihood of avalanches is likely lower for the central and eastern parts.  If you find yourself sinking into wet mushy snow past your boot-top, or see signs of natural wet snow avalanches, avoid traveling on or beneath steep slopes. 

Avalanche problems

  • Loose Wet

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

    Rain will continue to fall on the recent snow, with relatively heavier rainfall expected at mid and low elevations, especially near the western edge of the zone.  Areas near and east of Washington Pass, will likely see more sporadic and much lighter rainfall through Thursday.  Upper elevations may see wet snow during this period. 

    This does not look like a super soaker event, but we may start to tip the scales toward more widespread, larger wet loose avalanches.   That may already have occurred in areas near and west of Rainy Pass. For central or eastern areas, that may be Thursday or more likely Friday.   It's unclear if we'll receive enough rain this week to activate wet slabs and unleash very large avalanches. 

    If you find a wet, weak snowpack, avoid steep slopes over 35 degrees.  Rollerballing, pinwheeling, or natural wet loose avalanches are all signs that it's time to move to simpler terrain and check your overhead hazard. 

    Avalanches that begin in the highest elevations may quickly entrain more wet snow as they move to lower, warmer elevations.  If you're in a wet, stormy area, plan your route carefully and add more buffer between you and avalanche runouts connected to bigger slopes. Minimize your time under slopes with overhanging corncies.  At lower elevations, even small wet avalanches can be forceful enough to injure you or push you into other hazards, even if they're not big enough to bury you. 

    Upper elevations may see snow mix in over the next 24 hours along with strong west winds.  It's conceivable you could find fresh shallow wind slabs in the highest terrain, or more likely, you find dense new snow that's stubborn to trigger even in areas of drifted snow.  

    From earlier this season: 

    A small (D1.5) wet avalanche on Hwy 20 near Washington Pass. This occurred around 11/14-15 on the closed roadway.

    Photo: WSDOT

Avalanche Discussion

Periods of rain and occasional high elevation snow fell over the last 48 hrs, with weather stations recording 0.20" of water for Washington/Harts Pass, 0.70" for Rainy Pass, and closer to 1.50" way out west near Thunder Basin.  The foothills and eastern mountains received little to no precipitation through 5pm Wednesday.  Ridgeline winds have been strong out of the W-SW.  This weak but very persistent atmospheric river shows no signs of letting up through Friday, with a more significant shot of precipitation potentially pushing inland at the end.  While precipitation totals may vary across the zone, with temperatures above freezing for several days, you can count on a wet, gloppy snowpack to close out the work week. 

On Tuesday, an observer in the Silver Star area found schmoo-y snow conditions, but wet snow avalanches were limited to roller balls and small loose wet running below cliffs.  On Monday, an observer in the Silver Star area reported warming temperatures and light drizzle by late morning. Snow surfaces were becoming sticky and moist.  On Sunday, an NWAC forecaster in the Blue Lake area reported minor cracking in wind-drifted snow and easy triggering of loose avalanches in sheltered terrain. Prior to this, a stormy week delivered 2-3 feet of snow over the March 8th crust. 

There have been no recent observations of avalanches running on older persistent weak layers from mid-February. With the U-turn to wetter and milder conditions, these weak layers are worth keeping in mind. The 2/13 facets above the 2/7 crust can still be found on a variety of aspects and elevations at mid and upper elevations. 

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