Bulletin d’avalanche

Mt Hood

Northwest Avalanche Center
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Danger d’avalanche

Fri
Alpin
4 · Fort
Limite forestière
3 · Marqué
Sous la limite
3 · Marqué
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Périmé — ce bulletin a expiré 2 years ago. Vous consultez des conditions passées, pas le bulletin en cours.

Points saillants

The storm and avalanche danger will peak Wednesday night but strong winds will continue to move fresh snow on Thursday.  Assume you can trigger a large and consequential avalanche on any wind-loaded slope.  Very large avalanches may release from the upper mountain so don't linger in the canyon runouts even near forested terrain. 

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Very Likely
    Taille
    2–3

    While this storm will peak overnight in terms of heavy snow and extreme winds,  strong W-SW winds will continue moving snow onto the same lee slopes during the day.  Continue to avoid steep wind loaded slopes where you could trigger a large wind slab avalanche.  Look for clues like blowing snow, textured snow surfaces and fresh cornices to help you discern which slopes have been recently loaded.  Look for red flags like shooting cracks in firmer wind pressed snow as a sign you're likely to trigger an avalanche on nearby steep slopes.  Avalanches may break within storm layers or to older crusts (now several feet down) and run far distances at mid and upper elevations.   To enjoy the new snow safely, choose simpler, less wind-affected terrain without overhead hazard. 

    With winds continuing to load the same lee slopes on the upper mountain for several days now, we are in the window where a very large and unsurvivable avalanche could release from up high.  Give yourself an extra margin of safety and don't linger in the canyon runouts even at lower elevations. 

    Debris from a very large avalanche (est D4) in Clark Canyon. The avalanche ran several thousand feet to lower elevations and likely occurred Tuesday night.

    Photo: Ben Ticknor - MHMSP

Avalanche Discussion

A strong storm continues to pound the region, producing moderate to heavy snow and strong to extreme winds at Mt Hood.  Visibility was limited on Wednesday but MHM pro-patrol found debris from a very large avalanche in Clark Canyon that likely released Tuesday night.  It's a stark reminder of the powerful avalanches that can come off of Mt Hood following a multi-day storm cycle and often during periods of poor visibility. 

On Tuesday, as winds increased avalanche professionals reported that hard wind slabs were building throughout the day, and wind effect was present even in the trees.

Prior to this storm, 1.5-2 feet of low-density snow fell through Monday, creating the 2/24 interface. Deeper in the snowpack, a series of crusts and pockets of weak snow exist above the stout Early February Crust (EFC). These layers have produced inconsistent snowpack test results in recent days. They have generally been gaining strength but may not be fully healed. We wouldn’t be surprised to hear of an avalanche breaking down to the EFC during the current storm event. 

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