Bollettino valanghe

Mt Hood

Northwest Avalanche Center
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Pericolo valanghe

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

In sintesi

New snow and wind will continue to load the snowpack and create dangerous avalanche conditions around Mt. Hood. You could trigger large avalanches on slopes greater than 35 degrees, especially in wind loaded terrain. Carefully evaluate snowpack stability and seek out more wind sheltered terrain until the storm has run its course. 

Problemi valanghivi

  • Wind Slabs

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

    Continued heavy snowfall and strong westerly winds will continue to build large slabs of drifted snow across leeward terrain (NE-E-SE aspects). Sunday will mark day 3 of a significant loading event, so these slabs are likely growing large and will pack a punch if triggered, especially above 6500 ft. 

    You’ll find these slabs lurking on the leeward side canyons and ridges, below cornices, and on unsupported alpine features. As you travel, use visual clues like blowing snow and pay attention to the snow depth and stiffness. Drifts, dunes, rippled snow surfaces, and chalky snow pillows are visible clues that the wind has been at work. Shooting cracks or hard-over-soft layering are obvious signs that you found an unstable slab.

    (2/10/2024)

    Textured, rippled snow like this can help you identify potential wind slabs. 

    Photo: Joe Dellaporta

  • Storm Slabs

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

    Precipitation will continue to trickle in (.8-1.00 SWE) through Saturday morning, so you may find lingering storm instabilities in more sheltered areas, especially during the early morning hours or periods with heavy snowfall. Before jumping into steeper features, check to see how the new snow is bonding to the pre-existing surface. Look for cracking or snow sliding easily with snowpack tests. Consider choosing supported terrain and avoid rollovers until this storm snow has settled out. 

    (3/27/2024)

    An example of a small storm slab from last season. 

    Photo: Dallas Glass

Avalanche Discussion

Mt. Hood is in the midst of a multi-day loading event. Snowfall and strong winds are forecast to continue through Sunday morning before we see a brief break in weather and some possible short-lived sun-breaks during the afternoon hours. If the sun does come out; be on the lookout for signs of warming and small wet loose avalanches on steep, solar slopes. We have some uncertainty about the time of clearing and when clouds start filtering back in ahead of our next system, so be flexible with your plans, and be ready to head to shadier slopes if you notice rollerballs shedding or sticky, moist snow surfaces. 

This hasn’t been a bad storm cycle for Mt Hood so far. As I write this, the weather station at the base of MHM’s  has picked up 11 inches of new snow in the last 24 hours. The Mt Hood Meadows Pro Patrol, reported triggering small D1.5 wind slabs in middle and lower elevation terrain on Saturday morning. Other backcountry travelers reported strong winds and heavy drifting at 6000’ and storm instabilities settling out by lunchtime. Due to poor visibility, observations have been minimal above 6000 ft.

Leading up to this storm, we had a variety of surfaces across the terrain. Solar aspects ( SW-SE) consisted of scoured surfaces and a stout sun crust. Shaded aspects held old wind-drifted snow, some weakening surfaces, and even some isolated surface hoar. The big question moving forward will be how the new load of snow bonds to these, in some cases, weak surfaces. The best strategy during this loading event is to err on the side of caution by giving larger slopes some time to adjust to the new load and continue to gather more information.

Regioni coperte