Bollettino valanghe

Mt Hood

Northwest Avalanche Center
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Pericolo valanghe

Tue
Alta quota
3 · Marcato
Limite del bosco
3 · Marcato
Sotto il limite
3 · Marcato
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Non aggiornato — questo bollettino è scaduto 2 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

Another round of heavy snowfall and strong winds will maintain dangerous avalanche conditions around Mt.Hood. You can trigger large avalanches several feet thick on slopes greater than 35 degrees, especially in wind loaded terrain. Continue to avoid travel on and under steep, open terrain until this storm cycle has fully run its course. 

Problemi valanghivi

  • Storm Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Likely
    Dimensione
    1–2

    In more sheltered terrain, storm slabs may stay reactive to human triggering on Monday. I suspect these slabs will be most sensitive during the morning hours or during periods with heavy snowfall. Look for instability using test slopes, hand shears, and other simple tests. Shooting cracks are a sign you could trigger an avalanche if you head onto a steep slope. When in doubt just stick to simpler, sheltered, lower-angle terrain.

    (12/26/2024)

    An example of a storm slab. You can commonly trigger these on unsupported convexities. 

    Photo: Summit at Snoqualmie Pro Patrol

  • Wind Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Likely
    Dimensione
    2–3

    4-5 feet of recent new snow paired with strong wind speeds have built wind slabs several feet thick across exposed terrain around Mt. Hood.  These slabs will range in size and depth depending on elevation and could run far into canyon run-outs in favored exposed locations. In general, expect slabs to become thicker, denser, and more consequential as you climb above 6000 ft. High wind speeds from various directions have likely pushed these slabs further down slope than usual and may have loaded atypical aspects. 

    The best approach to manage this problem during stormy periods is to use avoidance. Avoid traveling on or under steep slopes that appear wind-loaded and use active drifting as a warning sign. It won’t be the day to test your luck as these slabs will be large enough to bury and kill people.

    (12/28/2024)

    Forecasters observed heavy drifting on Saturday. Blowing snow like this is a good indicator that wind slabs lurk nearby. 

    Photo: Joe Dellaporta

Avalanche Discussion

The parade of storms barreling into Mt Hood and the southern Washington volcanoes seem to be tapering, but we’ll have to deal with one more hit on Sunday evening as post-frontal showers deliver up to 1 inch of water equivalent and strong westerly winds. The bulk of the precipitation will come during the evening and early morning hours, so expect peak instability as you launch from the trailhead first thing. 

The south-side weather stations on Mt Hood picked up another 15-20 inches of new snow during the daytime hours on Sunday. This brings our storm cycle total to 50-60 inches since Christmas. All of this new snow rests over a stout crust that we labled as the 'Solstice Crust'. Snowpack tests have revealed good bond to this crust at lower and middle elevations, but snowpack observations have been limited above 6000 ft.

On Sunday, backcountry travelers unsurprisingly found reactive storm snow and triggered small storm slabs in sheltered terrain. The Mt Hood Meadows Pro Patrol also reported reactive conditions and triggered D1 storm slabs in their operational sheltered terrain. Above 6300 ft, observations have been sparse due to stormy conditions. 

It's been a big week for Mt Hood, so tree wells and creek holes will certainly be a real hazard to backcountry travelers. Keep your partners in close sight and carry communication devices. 

Help improve the avalanche forecast by submitting a public observation here.

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