Lawinenlagebericht

Mt Hood

Northwest Avalanche Center
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Lawinengefahr

Thu
Hochgebirge
2 · Mässig
Waldgrenze
2 · Mässig
Unterhalb
2 · Mässig
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Veraltet — dieser Lagebericht ist last year abgelaufen. Du siehst vergangene Verhältnisse, nicht den aktuellen Bericht.

Kernpunkte

Instabilities formed within recent storm snow layers will be slower to settle out on shaded aspects and within denser drifts.  You can still trigger them on steep, unsupported slopes with the largest slabs in wind-loaded middle and upper-elevation terrain. Mitigate your overhead exposure the sun makes any extended appearance.

Lawinenprobleme

  • Wind Slabs

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

    Moderate WNW winds redistributed the recent 12-15" of snow that fell since Monday. This snow overlies a crust on most aspects except middle and upper elevation shaded slopes. Wind-stiffened snow will be reactive in specific locations for another day as the slabs continue to gain strength. You can trigger them on slopes with wind-textured snow or those with lense-shaped pillows. Steer around such features below recent sharper cornices where the slope increases beyond 35 degrees. If you continue to find cracking on skin track tests or trigger small avalanches when you jump on steep micro terrain features in wind-loaded terrain, then you could trigger something more significant on a steep, open slope. In most cases, slabs will be soft but capable of entraining significant low-density snow. Firmer slabs will be harder to trigger, more widely propagating, and difficult to escape unscathed. When in doubt, fall back on lower angle terrain and smaller terrain features that avoid terrain traps.

    It looks like a mostly cloudy day for Mt Hood with some light snow in the afternoon, but not enough to impact the danger significantly. If snow transport does occur, fresh, shallow slabs may form on atypical aspects.

    Example: Cracking on up-track tests, a clear sign of instability in wind-loaded terrain.

    Photo: Joe Dellaporta

  • Storm Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Possible
    Größe
    1–1.5

    Storm snow remains soft, low-density, and 12-15" deep, but overlies a crust on all aspects at lower elevations. These soft slabs may change dynamically throughout the day as temperatures rise and fall.  Keep evaluating them and anticipate that you can trigger one on steep slopes approaching 40 degrees or where the slope rolls out from under you. Slabs could release within the recent storm snow or at the crust and any avalanche would entrain plenty of cold snow. Lower your risk threshold in the presence of terrain traps such as creeks or gullies. 

    (12/26/2024)

    You may find slabs like this in wind drifted areas or in open, steep terrain. 

    Photo: Crystal Mountain Pro Patrol

Avalanche Discussion

On March 17th, riders triggered a large slab that killed two people east of Broken Top Mountain in the Central Oregon Cascades. To our north, multiple experienced professionals have been surprised in the Washington Cascades this week and we don't think there's any reason to believe Mt Hood is immune. The snow is high quality, but dangers are present, and instabilities are slower to heal during periods of cold temperatures. Mt Hood has picked up around 60" of snow in the past week. The snowpack is layered, wind-affected, and it's difficult to keep up with the interfaces, crusts, and slab properties at middle and upper elevations within an intense storm cycle. All that is to say, it's worth dialing it back and taking the travel advice seriously in times like this. Slab reactivity can change quickly with a bit of daytime warming as we approach springtime. And if significant solar radiation makes it through the clouds on Wednesday, expect dry snow to shed off rocks, cliffs, and trees, creating point release avalanches. Pinwheels or moist snow surfaces are all the information you need to seek shaded aspects free from overhead exposure.

Mt Hood Meadows reported widespread reactive soft slabs in control on Tuesday morning within the 10"+ of storm snow. Most slabs broke 2-6" deep in wind-affected middle and upper elevation terrain and entrained significant snow. At lower elevations, storm slabs lacked energy. That could change with settlement and if temperatures warm at all on Wednesday.

At middle elevations on shaded aspects where deep unconsolidated snow is present, snow immersion suffocation (SIS) remains a possibility in treed terrain. Travel with a partner and keep an eye on them. Small trees, in particular, can create dangerous voids just below the surface.

You can help us gather more data by submitting an observation HERE or via the Avy App.

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