Avalanche forecast

Mt Hood

Northwest Avalanche Center
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Avalanche danger

Wed
Alpine
4 · High
Treeline
4 · High
Below
3 · Considerable
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Highlights

Continued snow and wind will maintain very dangerous avalanche conditions Tuesday.   Avoid avalanche terrain at upper elevations and don't linger in large runouts.  Conditions will likely worsen Tuesday afternoon and night at lower elevations as a new storm with rising snow levels impacts the area. 

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Very Likely
    Size
    2–3

    Strong winds will continue to transport new and recent snow through Monday, maintaining very dangerous avalanche conditions near and above treeline.   Strong winds may have formed wind slabs in unusual places and built deep slabs on lee upper elevation slopes.  Continue to avoid traveling on or below large open slopes capable of producing large avalanches.  With every day without a real break in the storm cycle, we will have increasing uncertainty about the likelihood of natural very large avalanches (D3 or larger) that may run from upper elevations.  Even at mid elevations, assume you can trigger an avalanche on any steep slope with deeply drifted or firmer wind-pressed snow.  Visibility will likely continue to be a challenge above treeline, producing challenging route-finding and travel conditions. 

    (12/8/2021) Where you find long shooting cracks in freshly wind drifted snow, avoid steep slopes. Photo: Matt Primomo

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1–2

    Snowfall rates will likely pick up again Tuesday afternoon as a new storm rolls into the area and snow levels slowly rise.  Storm slabs may break down deeper into the recent snow and become large even below treeline.  Steer around convex rollovers and steep unsupported slopes.  Look for signs of instability like cracking in the new snow and recent avalanches as an indicator to stay off of similar slopes.  If the storm intensifies Tuesday faster than forecast, be prepared to retreat to simpler terrain and lower angle slopes.  

    (12/25/2021)

    A storm slab released in steep forested terrain.

    Photo: Mt Hood Meadows Patrol

Avalanche Discussion

It was a wild day on Mt Hood and the surrounding area with heavy snow down low and whiteout conditions/strong winds.  Through 5 pm Monday, the Mt Hood Meadows base plot recorded about 2 inches of water/27" of snow since the storm began Sunday evening, but those numbers are likely undercounts based on the winds.  Strong W-SW winds were recorded at the Meadows 6500' station, but again winds at higher elevations were stronger than what was recorded on weather stations due to partial riming (icing).  The Timberline ski area was closed.  Mt Hood Meadows Patrol had the upper mountain/lifts closed and on the lower mountain reported widespread touchy storm slab avalanches during avalanche mitigation.  The avalanches broke within the new storm snow and were sometimes triggered while approaching steeper terrain.  Despite the extensive and ongoing wind transport, at least below treeline, the slabs were soft and had not yet become denser wind slabs.  There were no observations from the upper mountain. 

Winds picked up in advance of the storm on Sunday. Observers noted wind transport increasing on Sunday ahead of the storm and wind pressed snow surfaces below treeline.  Prior to this system,  very enjoyable and plentiful cold low density snow could be found on much of the mountain.  An active storm track over the next several days will likely keep the avalanche danger elevated.  Remember that very large avalanches can release from the upper mountain and run thousands of feet down the main canyons during or after multi-day storm cycles. Keep this on your mind when choosing where to travel even at lower elevations, and don't be lulled into complacency during short lulls in the action.  A very large natural avalanche occurred on 12/23 on the Newton Clark Headwall. Find out more information in this REPORT in the NWAC Avalanche Occurrence Database.  It's a great reminder of the higher uncertainty surrounding deeper layers in the alpine snowpack. 

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