Avalanche forecast

Southern Wallowas

Wallowa Avalanche Center
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Avalanche danger

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Out of date — this forecast expired 2 years ago.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

Highlights

New snow and wind-blown snow will continue to stress our weak upper snowpack structure.     While the largest avalanches will likely be in wind-drifted snow, smaller avalanches could be numerous in wind-sheltered areas.  A big change to the snowpack demands a big step back in our terrain selection and mindset. 

This forecast is sponsored by Wallowa County Gamblers Snowmobile Club

Avalanche problems

  • Storm Slabs

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

    At least 12" of new snow was received in the Southern Wallowas since yesterday morning.  Another 2-4" of snow is on the way for today.  The new snow has fallen on a variety of weak surfaces, including 10-12" of weak faceted sugar snow, surface hoar, slick melt-freeze crusts, and in some locations, even crust/facet sandwiches.   We do not expect this new snow to bond well to these surfaces, and time is needed for things to stabilize.  This makes for a tricky situation to assess.  While not yet a "persistent slab" problem, these avalanches could fail in surprising ways where the new snow/old snow interface consists of faceted snow.   Stay out of the runouts of avalanche paths while a remotely triggered avalanche wouldn't be out of the question.  

    Observers in the Southern Wallowas yesterday reported widespread collapsing and cracking of the snowpack throughout the day and natural avalanches along the roadcuts of the Cornucopia Highway.  Look for a more detailed observation from Silas of Wallowa Alpine Huts later today.  

    Silas of Wallowa Alpine Huts got this photo of a natural storm slab on a road cut along the Cornucopia Highway. 

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1–2.5

    Ample new snow for transport combined with gusty winds have built dense slabs of snow on leeward ridgelines and cross-loaded mid-slope convexities.  You will most likely find these wind slabs downwind of scoured areas or below corniced ridgelines.   Look for clues such as dune-like and rippled formations of wind-blown snow.    Wind slabs may be sitting above layers of weak and faceted snow.  They will be extra sensitive if you find this setup.   Avoid wind-loaded terrain, especially where slope angles exceed 30 degrees.  

    (12/26/2024) Photo: Caleb Merrill

Avalanche Discussion

A return to active winter weather is here, ending the January dry spell.  Our last measurable snowfall prior to this was on January 10th.   The extended high pressure brought with it plenty of sun, wind, and mostly cold temperatures.  These conditions created a variety of conditions on the surface of the snow.   As we introduce a new load to this weak snowpack, it will need time to settle. 

The Southern Wallowas and Northern Blues avalanche forecast zones have received enough new snow to raise the alarm bells.  It's pretty obvious in these zones that a step back is necessary. 

The "tweener" amounts of new snow (4-6") in the Elkhorns, Western Wallowas, and Northern Wallowas make assessing the new snow instabilities a bit trickier.  Obvious signs of instability may not be clear and present, but anywhere there is 6-8" of new or wind-blown snow on a suspect interface, use caution and consider avoiding avalanche prone slopes.  What are the suspect interfaces you ask?  See below. 

  • On shady and sheltered northerly aspects that have been protected from the wind, the new snow will not bond well to the 10-12" of weak, sugary facets and/or surface hoar.   The new and wind-blown snow may be able to hang in the balance for some time before a trigger is introduced to the equation.  Don't let the trigger be you! 
  • On solar aspects, the new and wind-blown snow will not bond well to firm surfaces that have gone through multiple melt-freeze cycles.   If you find areas where weak sugary snow exists below these crusts, a greater degree of caution should be used.  

As always, be on the lookout for the freebie signs of unstable snow: recent natural avalanches, shooting cracks, and whumphing of the snowpack.    However, we should be treating this set up similar to a persistent slab problem, where the usual signs may be hidden and remotely triggering avalanches will be a possibility.    This complex scenario demands a conservative approach to your terrain selection as we reach the upper end of snow totals by the end of the day.   The snowpack is waiting to reach a tipping point of stress over strength.  It will likely occur at some point this weekend.   This creates a challenge for backcountry travelers navigating avalanche terrain.  The best approach will be to utilize a conservative mindset as we see how this all unfolds.   Be patient.  

Check out forecaster Tom Whipple's observation from last week in the Southern Wallowas here.  

Observations:  Observations have been sparse.   Add value to your avalanche forecast.  Help us reduce uncertainty.  This weekend will be an ideal time to submit an observation if you get out in the backcountry.  

Eastern Oregon Backcountry Festival-Bid on the Online Auction Now!!!

Join us for the 13th Annual Eastern Oregon Backcountry Festival Today and Tomorrow! 

  • Feb. 1: Kip Rand Backcountry Race (Anthony Lakes) Race starts at 8 AM, show up at 7:45.  Companion Rescue Clinic 10 AM, Snow Pack Obs Clinic 1 PM.  Live music by Wanderlust 3:30 PM Main Lodge with raffle.  (You must show up 15 min early for clinics and race at EOBF tent on S. Side of Rental shop.)
  • Feb 2: Tour with WAC Staff:  Ski tour into Angell Basin to better understand how to safely travel in avalanche terrain.  Please consider purchasing raffle tickets, bidding on an auction item, or donating $50 to the Wallowa Avalanche Center if you are planning to attend this tour.

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