Avalanche forecast

Mt Hood

Northwest Avalanche Center
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Avalanche danger

Sat
Alpine
3 · Considerable
Treeline
2 · Moderate
Below
2 · Moderate
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Out of date — this forecast expired 3 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

We have a lot of uncertainty following a multi-day storm cycle in the Mt Hood area, especially on the upper mountain.  Ease into terrain on Friday, taking note how the snowpack changes across space and elevation.  Take care to avoid slopes above terrain traps where even a smaller avalanche can do more damage. 

Avalanche problems

  • Storm Slabs

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

    Several feet of snow has fallen since this storm cycle began on the 16th, with deeper drifts likely at upper elevations.  Give the recent storm snow time to settle and avoid steep open slopes at upper elevations capable of producing large avalanches.  At lower and mid-elevations, avoid convex rollovers and very steep unsupported slopes. 

    Given how this storm cycle has played out, you may encounter very different conditions across the mountain and at different elevations.  It will be an important day to track changes in the snow as you move around and avoid assuming stability in one area applies somewhere else. 

    (12/8/2023)

    Hand pits are a great way to look at the recent storm snow. Look for strong over weak layers and places it fails easily. 

    Photo: Andy Harrington

  • Loose Wet

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

    Temperatures are expected to warm on Friday along with some potential afternoon sunbreaks.  The exception will be colder air trapped below 5000' due to temperature inversions and low-level east flow. The sweet spot for wet loose avalanches could be above the inversion at mid-elevations where new storm snow is looser and less wind affected.  This might be one of those days where you don't see natural wet loose avalanches and they're resistant to trigger, but if you get one going there's a lot of moist snow to entrain.  Where you find deep and heavy snow, stay safe by avoiding very steep slopes where you could get pushed into a terrain trap like trees, gullies, or over cliffs. 

    Even a small wet loose avalanche could do damage when paired with a terrain trap. 

    Photo: Mt Hood Meadows Patrol (4/11/23)

Avalanche Discussion

This latest round of our storm cycle didn't go as planned with temperature and wind fluctuations painting a highly variable picture across the zone both spatially and vertically.  The big picture is the mountain received over 4" of water and counting since 1/16.  This has translated into at least 2' of snow above 5000' with more likely at higher elevations.  Temperature fluctuations have introduced at least 2 breakable crusts within the storm snow at mid-elevations that may present as an ice layer above treeline.  Cold east winds caused localized temperature inversions like the one near Ski Bowl where temps stayed in the 20s on Thursday.  By the time the storm wraps up Friday morning, some areas may see a freezing rain layer, capping all of this recent snow. 

The only thing we can be certain about is that the lack of direct observations outside the Meadows ski area and weather stations leaves a lot of unanswered questions as we exit this storm cycle.  On Thursday, the Mt Hood Meadows patrol found storm slabs at lower elevations were stubborn to trigger during avalanche mitigation.  When they did run, they were sluggish but entrained moist underlying storm snow as they ran downslope. 

While avalanches are more likely to fail within the new snow, there are a few layers in the upper snowpack worth tracking: 

-1/16 Interface: This interface is now likely 1-3' down in the snowpack.  A very slick ice crust formed in many areas above 5000ft. Lower in the terrain, soft unconsolidated snow lingered. 

-Early January Facet/Crust Layer: This potential weak layer is several feet deep! While we haven’t seen avalanches on it recently, deep persistent slabs have occurred to the north (West South Zone) and south (Central Oregon Avalanche Center). Will this new load wake it up? Hard to say. These much bigger and deeper slides would most likely occur on NW-N-E aspects above 5500ft where significant snow existed before the New Year.

Regions covered