Lawinenlagebericht

Stevens Pass

Northwest Avalanche Center
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Lawinengefahr

Thu
Hochgebirge
2 · Mässig
Waldgrenze
2 · Mässig
Unterhalb
1 · Gering
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Veraltet — dieser Lagebericht ist 3 years ago abgelaufen. Du siehst vergangene Verhältnisse, nicht den aktuellen Bericht.

Kernpunkte

Another inch of new snow may fall, but the wind is the real story.  Easterly winds may readily transport newly fallen and old snow into reactive slabs on open, wind exposed slopes. Identify these through textured surfaces or stiffened snow, and consider steering around steeper or consequential slopes as they'll be freshly formed on Wednesday. 

Lawinenprobleme

  • Wind Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Possible
    Größe
    1–2

    As the morning breaks the winds should be just starting to ease. By then, the damage will mostly be done. Easterly winds at lower and mid elevations and southerly winds at upper elevations should drift snow from the past couple days into deeper areas, scour others, and create cohesive slabs on some slopes. Look for wind textured surfaces or sharp drifts and feel for thicker or stiffer slabs. Look for signs of instability as you travel, especially shooting cracks or recent slab avalanches if visibility allow. 

    Small test slopes can be helpful in evaluating instabilities if slabs are less than about a foot deep. Quick hand shears can help to identify weak layers and failure layer characteristics. We expect enough recently drifted snow to create hazard for slab avalanches below ridges, and with cross slope and upslope drifting. This type of wind 'event' can even create hazard at lower elevations on heavily wind exposed slopes. Steer around fresh drifts and thick pillows on steeper slopes, or slopes of increased consequences. Slabs could be fairly reactive on Wednesday, as they'll be fresh.

    (12/23/2023)

    Obviously wind textured snow near a sub-ridge of Rock Mountain at 6,300ft. Look for clues like this.

    Photo: Matt Primomo

Avalanche Discussion

A strong pressure gradient between the east and west Cascades will drive the moderate easterly winds into Wednesday morning. New snow should continue to trickle in during the daytime as winds decrease. Visibility may be somewhat limited during the day, certaintly not the same bluebird conditions above the clouds like Tuesday was. 

Stevens Pass picked up about 10" of new snow since the 21st, and about half of that fell on Christmas night. On Tuesday morning, Snow safety at Stevens Pass Mountain Resort reported fairly widely propagating slabs just 2-6" deep with control work, and some dry loose sluffing. Conditions settled out fairly quickly during the day, and became less reactive later. Other observers found minimal instabilities, but the sun had warmed steeper south facing slopes and sent pinwheels into action. Travel conditions and coverage have improved substantially, but its still thin. Beware of hitting exposed rocks, stumps, and creeks.

On most slopes, the most recent crust was buried on December 22nd. On steeper due south slopes and some open terrain, the crust is a stout combination of rain and sun events from the past couple weeks. Elsewhere, the upper snowpack is a series of thin, brittle crusts and weak, faceted layers below the 12/22 interface.

Stevens Pass Ski Area is open. Check uphill policies HERE. You can contribute to the forecast! Let us know what you found by submitting an observation HERE. 

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