Avalanche forecast

Mt Hood

Northwest Avalanche Center
View on map

Avalanche danger

Wed
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
3 · Considerable
Open full map
Out of date — this forecast expired 4 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

The threat of natural avalanches decreases slightly as a major storm begins to ease Tuesday while slopes remain primed for human-triggered avalanches. Avoid all wind-loaded upper-elevation avalanche start zones and connected terrain at lower elevations. Continue to stay off open slopes steeper than 35 degrees until the storm snow layers have time to heal.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1.5–2.5

    With the winds and snowfall starting to decrease, natural avalanches at upper elevations should be unlikely on Tuesday. However, there's enough of a threat that it's worth continuing to steer around terrain connected to upper elevation start zones, particularly during periods of heavy snow, wind, or sunshine when the snowpack experiences rapid change. Near treeline we expect you can trigger small to large wind slabs. As you ascend into wind-affected terrain, note subtle changes to the surface snow appearance and texture. Winds may stiffen low-density snow to form upside-down layering. In some cases, these slabs may be subtle density changes while in other cases you might find firm, supportable layers overlying lower density snow. Any firm over weak snow structure should be enough reason to steep slopes nearby a margin of safety.  Winds can channel slabs onto a variety of aspects, but the greatest threat for wind deposits will be on SE-E-NE-N aspects. Avoid all wind-loaded terrain steeper than 35 degrees fresh and recent wind slabs need time to heal.

    Example: Fresh cornices and actively blowing snow are visual clues you can use to help identify wind-loaded slopes to steer around. 

    Photo: Dallas Glass

  • Storm Slabs

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

    By the time you're in the terrain on Tuesday, we expect you'll find 3 ft or more of snow above the 4/8 crust. Variable rates of snowfall and snowflake structure will continue to create mid-storm interfaces that will remain reactive on Tuesday. Interfaces near the surface of the snow may be easy to trigger while layers more than a ft are more likely to fail on an unsupported slope to produce a large avalanche. While interfaces were present on Monday, the cold snow lacked a slab structure. Periods of sun or wind could change that. If the upper snowpack remains cold and dry, anticipate a mixture of storm slab and dry loose character to the avalanches where snow entrains, but may not propagate widely.  Focus your attention on the upper 2 ft of the snowpack which haven't had time to stabilize during the heavy snowfall. Use simple slope tests or column tests to identify weak interfaces and cohesive layers in the upper snowpack. When in doubt, avoid all open slopes steeper than 35 degrees and be prepared that you could slabs deep enough to cause trauma in open glades. 

    Example: Storm slab.

    Photo: Public Observation

Avalanche Discussion

NWAC is aware of a possible avalanche fatality at Mt. Hood Meadows and is in communication with local authorities. You can read our full statement here.

47" of snow have fallen at Mt. Hood Meadows since Friday as another late-season storm cycle impacts Mt. Hood with strong winds delivering blizzard conditions to near and above treeline terrain. Given all the recent snow, very large avalanches remain a possibility. Keep this in mind if you are considering crossing below very large avalanche slopes, even valley flats, connected to the upper mountain.

Avalanche activity has been ongoing since Saturday. On Monday, Mt. Hood Meadows Patrol easily triggered small-large avalanches that exhibited storm and dry loose characteristics.  NWAC forecast Andrew Kiefer traveled in the Mitchell Creek area adjacent to the resort and found dry, low-density storm snow with several mid-storm reactive interfaces down 4" and 12" that were associated with the avalanche activity. You can read his full report here. On Sunday, Mt. Hood Meadows Patrol reported several wind slabs (up to size 2, large), and dry loose avalanches in less wind affected terrain. On Saturday, a public observation reported a large slab in wind-loaded terrain above Newton Creek on an E aspect.

 

Regions covered