Bulletin d’avalanche

Mt Hood

Northwest Avalanche Center
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Danger d’avalanche

Mon
Alpin
2 · Modéré
Limite forestière
2 · Modéré
Sous la limite
2 · Modéré
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Points saillants

Sustained moderate winds have redistributed a half foot of low-density snow into slabs you can trigger near and above treeline on Sunday. Morning sunshine increases the chance of natural or human-triggered wet avalanches entraining wet, sticky surface snow. Navigate around potentially wind-loaded and sun-affected slopes 35 degrees and steeper.

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–2

    24-hour snow totals may reach 6" by Sunday morning while moderate winds and strong gusts continue to drift snow through Saturday night. Much of the wind transport occurred after the winds shifted from E to W on Saturday.  At upper elevations, slabs may be large in isolated areas and likely rest on an old snow interface. Near treeline, slabs should be primarily small and may rest on either a thin crust or old snow (shaded aspects). As you ascend, attempt to gauge the amount of recent snow and degree of wind transport in your terrain.  Larger variations in snow depth from windward to leeward slopes indicate that slabs may be larger and more reactive. If you identify these variations in snow depth, ascend into wind-textured snow, or encounter firm over weak snow layering, steer around steep slopes where snow might have drifted 6" or deeper.

    Example: Wind textured snow. Wind slabs may lurk on leeward slopes nearby.

    Photo: Andrew Kiefer

  • Loose Wet

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–1.5

    Morning filtered sunshine and lighter winds should destabilize 4-6" of fresh snow on easterly and southerly aspects. Any cold may destabilize with as little as 10 minutes of direct sunshine.  Expect a rapid transition to sticky surface snow and rollerballs, then point releases initiating from snow shedding off trees, rocks, or cliffs. Move to cooler, shaded aspects and reduce your exposure to steep slopes in the sun. Entrainment of snow should be limited by breakable crusts, but these avalanches may continue to build momentum on a long, steep slope up to size 1.5 and could easily knock you off your feet or bury you in a terrain trap.  If the high clouds and winds increase during the afternoon as forecast, wet loose may not make it onto westerly aspects.

    Example: A loose avalanche triggered on a steep slope in full sunshine.

    Photo: Matt Primomo

Avalanche Discussion

Mt Hood received nearly 80 in of snow since April 8th. Snow showers should taper Saturday night and we're expecting a dry and slightly milder day on Sunday with freezing levels rising to 4500 ft.

As of Saturday afternoon, around 4" of snow had fallen as winds increased into the moderate range with strong gusts.  Moderate winds were building slabs in the Mt. Hood backcountry at 6000 ft. On sun-affected aspects, the recent snow sits on breakable crusts that formed with intermittent sunshine Thursday and Friday and also resulted in minor loose wet avalanche activity.  The crusts sit above 3-5in of snow that accumulated Thursday night. No new avalanches were reported since early Thursday when Mt Hood Meadows patrol triggered a few large wind slabs with explosives in easterly upper elevation terrain. Loose-dry avalanches and storm slabs have been reported as well, but have been small and shallow. All the new snow has settled to 4-5ft and sits on the prominent 4/8 crust. Recent storms really built up the snowpack and improved low elevation coverage, and snow depths on Hood are 106-110% of normal for this time of year.

NWAC is aware of a possible avalanche fatality at Mt. Hood Meadows on 4/5. We are actively working with local authorities to gather more information about the incident. This incident involved a solo snowboarder and a multi-day SAR effort. You can read our initial statement here. We will update the statement early next week (week of April 18th). 

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