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
2 · Moderato
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In sintesi

Dangerous avalanche conditions will persist into Monday following a winter-esque weekend storm.  Large slab avalanches in wind-drifted snow are likely but you may also encounter loose snow avalanches in wind-sheltered terrain.  Practice deep snow safety - travel with a partner and keep them within eyesight. 

Problemi valanghivi

  • Wind Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Likely
    Dimensione
    1.5–2.5

    3-day storm totals through Monday afternoon should tally around 3 feet in the Mt Hood area - not too shabby for early April.  With this much snow, we need to give the snowpack time to settle and stabilize. Strong westerly winds at the beginning of the storm were less intense Sunday but still moving copious amounts of low-density snow along ridgelines and at upper elevations. NW winds will continue to move new snow through Monday.    

    If you trigger a slab avalanche Monday in wind-drifted snow, there's a good chance it will be large and dangerous.  Avoid the downwind side of ridges, below cornices, and under rock and cliff bands.  Visual clues like shooting cracks, blowing snow and slopes that appear textured or ‘fat’ will help you identify which slopes to avoid. Cornices are likely large and sensitive so give them a wide buffer if traveling along ridgelines.  Cornice fall would be an easy way to trigger an avalanche on the slope below.  You can stick with lower angle slopes not connected to large start zones and less wind-affected terrain to deal with this problem. 

    Storm slabs will be less likely to trigger on Monday but still possible on specific slopes.  Steer around very steep convex rollovers and unsupported terrain.  You can use small test slopes or quick snowpack tests to test how the new snow is bonding in your area. 

    (3/4/2023)

    Use visual clues such as fresh cornices to help you identify wind loaded slopes. 

    Photo: Joe Dellaporta

  • Loose Dry

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1–1.5

    Dry or wet loose avalanches are both possible on very steep slopes Monday.  These avalanches will likely be small and manageable on their own but they can pose a hazard around terrain traps like cliff bands, steep trees, or gullies.  

    On cooler and shady aspects, fast-running dry loose avalanches or "sluffs" may catch you by surprise and knock you off your feet.  Monday will be unseasonably cool and at times showery, but it's spring-time and it's hard to discount the April sun, especially on the lee (eastern) part of the mountain. If the sun comes out and you feel the snow surface become heavier, see rollerballs or pinwheels, the likelihood of wet loose avalanches is on the rise.  You can easily mitigate this problem by moving to lower angle or shadier slopes. 

    (4/2/2023)

    Dry loose avalanches were easy to find up and down the Cascades on Sunday. You may see or trigger more point releases like this on Monday. 

    Photo: Rachel Grondvold

Avalanche Discussion

April continues to deliver great conditions as the low-density snow piled up on Sunday.  Weekend storm totals since Friday afternoon are around 2-2.5'.  Professionals reported deep trail-breaking along with dry loose avalanches running well on steep slopes.  Winds were moving the new snow along ridgelines and at upper elevations.  In the Gunsight Ridge area, almost 2' (55 cm) of storm snow could be found above the 3/31 crust.  Forecaster Joe Dellaporta reported that the tree well hazard was real. We've had some close calls around the Cascades over the last week - please practice deep snow safety and keep your partner in sight until the new snow settles. 

On Saturday the Mt Hood Meadows Pro Patrol triggered large avalanches in wind drifted snow and several soft slabs in more sheltered areas. Visibility remained poor, so observations from higher elevations were limited, but we suspect a natural avalanche cycle may have occurred. The Timberline Ski Patrol triggered soft slabs in more sheltered areas. They reported these avalanches failing about 12-15 inches deep above the most recently buried crust. Similar public reports came in from Newton Creek. 

Leading up to this storm most aspects (besides northerlies) below 6000 ft held a melt-freeze crust at the surface. In some locations observers even noted graupel resting on this crust. 

Last week observers reported weak snow associated with a crust that sits several feet below the snow surface. This layer was likely responsible for the isolated whumphs in the Gunsight Ridge area and propagating results( observation) near Vista Ridge. While isolated and unlikely, keep this information in mind especially if you find yourself traveling on higher elevation, northerly aspects.

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