Bulletin d’avalanche

Mt Hood

Northwest Avalanche Center
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Danger d’avalanche

Wed
Alpin
2 · Modéré
Limite forestière
1 · Faible
Sous la limite
1 · Faible
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Périmé — ce bulletin a expiré 3 years ago. Vous consultez des conditions passées, pas le bulletin en cours.

Points saillants

Avalanche danger increases markedly at upper elevations, once the Christmas crust near the snow surface disappears as you ascend. Steer around steep slopes where you find drifts of wind-stiffened snow, noting firm over weak snow layering. Keep an eye upwards, identifying and large avalanche slopes originating on the highest slopes of Mt Hood. At middle elevations, any slabs should be isolated and easily spotted atop the slick crust.

Problèmes avalancheux

  • Wind Slabs

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

    Your greatest danger will be at the highest NWAC forecast elevations in the morning hours, with hazard increasing further above NWAC forecast elevations. It may be tempting to climb high to find dry snow, but also recognize that the most uncertainty exists at these elevations. You could find a rime crust to the top of NWAC forecast elevations and beyond. You could also get above the Christmas crust where wind slabs may be thicker, more widespread, and more difficult to steer around. At the same time, parts of the upper elevation band may have isolated shallow slabs drifting atop a crust. These conditions described range from potentially "considerable" levels of hazard to "low" levels of hazard. Thus, prepare to inform your travel plans at upper elevations and beyond with detailed observations. Deep wind-stiffened snow, cracking snow surfaces, or evidence for recent slab activity would be signs that more widespread danger exists in your terrain and you should dial back your terrain selection. If you encounter "dust on crust," travel hazards such and your ability to self-arrest will remain your greatest concern.

    You may find surfaces like this on upper elevation, exposed aspects. A very obvious sign of recent wind transport.

    Photo: Joseph Dellaporta

Avalanche Discussion

Christmas brought a mixed bag of 2-3" of snow, capped by a glassy half inch of breakable freezing rain crust, and then rain that fell up to at least 6600 ft on Mt Hood. This consolidated and likely wetted new snow and the 2-4" of old snow from last Friday's storm (see snow profile in the gallery). The freezing rain crust limited avalanche activity. However, the storm has brought 1.54 inches of snow water equivalent by 4 PM Christmas afternoon with another half inch of various precipitation types arriving overnight with snow levels lowering slightly toward the end of the storm. Consider these liquid amounts if you do get above the Christmas day rain/snow line because the avalanche danger could rise dramatically. Mt Hood Meadows and Timberline have 1.5 ft and 2 ft bases, respectively. At all but the highest elevations, the avalanche danger will be less than the travel hazards.

  • A breakable Christmas Crust may refreeze and become very slick. Arresting a fall may be difficult without appropriate 'sharps' for self-arrest. Carefully consider your preparedness and the consequences of a fall before crossing any steep, icy slopes.
  • Early season conditions and hazards exist at lower elevations, on wind-stripped aspects, and along ridgelines. Rocks, roots, grass, and stumps will exacerbate any fall on ice or potentially a small avalanche.

The sun could make an appearance Tuesday late morning into the afternoon hours. If the sun does hit areas of fresh snow 6" or deeper, rollerballs are your clue to steer out from under steep slopes before wet avalanches initiate.

If you get up on the mountain, let us know what you see by submitting a public observation.

Régions couvertes