Boletín de aludes

Mt Hood

Northwest Avalanche Center
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Peligro de aludes

Tue
Alta montaña
3 · Notable
Límite del bosque
3 · Notable
Bajo el límite
2 · Moderado
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Desactualizado: este boletín caducó 5 years ago. Estás viendo condiciones pasadas, no el boletín vigente.

Lo esencial

You can trigger a large slab avalanche on a wind-loaded slope once you transition out of thick tree cover. Approach upper elevation slopes with caution, noting firm snow layers, cracking snow surfaces, and wind-textured slopes as evidence to avoid steep lee slopes. When in doubt, travel safely along ridgelines and slopes scoured down to a crust.

Problemas de aludes

  • Wind Slabs

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Likely
    Tamaño
    1–2

    Snow showers and moderate ridgeline winds should already reactive slabs Sunday night. Light snow showers with less wind transport on Monday may mask areas of wind-affected snow. Slabs could be large, propagate widely, and run far and fast on a crust. Note the average snow depth as you move through less wind-affected below-treeline terrain. Probe the upper snowpack for upside-down snow layers as you ascend into more exposed terrain.  Use areas shallower areas of snow to gauge where the winds have drifted snow deeply on the other sides of the ridgeline. If you see shooting cracks in the freshly drifted snow,  assume you can trigger a slab avalanche on nearby slopes.  Avoid all wind-loaded slopes steeper than 35 degrees.

    (2/20/2022)

    Example: Skier triggered slab on a steep, unsupported wind-loaded slope. Photo: Pete Durr, USFS Backcountry

  • Storm Slabs

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Possible
    Tamaño
    1–1.5

    It is possible to trigger a storm slab 8-12" thick in wind-sheltered terrain. These slabs may break within storm layers or down to the 02/14 crust. Reports indicated generally fair bonding of the new snow to the crust, but periods of more intense snowfall could destabilize intra-storm layers. Use simple slope tests to gauge the reactivity of recent storm layers before jumping into steep or unsupported open slopes below treeline.

    This snow will go a long way to refresh the riding and traveling conditions but it won't bury rocks, tree stumps, and all the other ground hazards that have become exposed over the last month.  A small avalanche can ruin your day in the wrong piece of terrain.   

    Example: A storm slab released in forested terrain.

    Photo: Mt Hood Meadows Patrol

Avalanche Discussion

Mt. Hood picked up around 10" of fresh snow by the end of the day on Monday. Strong to extreme winds picked up Saturday, but dropped into the moderate to strong range as the snow ramped up Saturday evening. Most of the snow arrived Saturday night with light snow showers and wind continuing through the day on Saturday. The new snow sits on old snow/crusts buried 02/19.  In general, we are not concerned about the recent storm snow stepping down to the 02/14 crust. 

Spring weather changes rapidly. If the sun comes out for a period of time, expect steep slopes with direct sunlight to destabilize and form shallow loose avalanches that could knock you off your feet in steep terrain.

Enjoy the improving conditions this week while traveling safely.  And please, let us know what you see!

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