Bollettino valanghe

Mt Hood

Northwest Avalanche Center
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Pericolo valanghe

Thu
Alta quota
2 · Moderato
Limite del bosco
2 · Moderato
Sotto il limite
1 · Debole
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Non aggiornato — questo bollettino è scaduto 6 months ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

This isn't your typical moderate danger day on the upper elevation slopes of Mt Hood. Large firm slabs have been slow to heal and continue to propagate widely. Steep, unsupported and high consequence wind loaded terrain features need more time to heal.

Problemi valanghivi

  • Wind Slabs

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

    A layer of lower density snow underlying firm wind deposits has created a difficult to manage slab problem on the upper slopes of Mt Hood. Although the reactivity continues to decrease, the consequences have not. Large slabs triggered in mitigation at Mt Hood Meadows both Monday and Tuesday were reactive to very small amounts of dynamite, suggesting that a rider could easily trigger them as well. 

    Given the size of the avalanche problem (potentially very large) above 6500 ft, it's unwise to commit to large wind-loaded slopes on the eastern half of the compass. Although reverse loading formed shallow deposits on W aspects on Tuesday, Monday's winds from the WSW formed the larger slabs that are most concerning. Below around 6500 ft, softer slabs should be healing more rapidly with another day of sunshine and mild temperatures. T

    Given the strength of recent WSW winds,deposits may lurk near ridgelines, but also well below typical startzones around moraines and even low on canyon walls. Shooting cracks and hollow-feeling snow are both key indicators that the snow needs more time to settle before you engage with consequential terrain.

  • Loose Wet

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

    Thin crusts will break down surface crusts with another day of sunshine and lighter winds on Wednesday. As snow surfaces become moist, expect the potential for rollerballs and snow around warming rocks and cliffs to entrain surface snow to produce generally small avalanches within less wind-affected snow. Although wet loose avalanches will be generally small, they build mass and fan out as they descend. Keep an eye on the slopes above you and head toward cooler shaded slopes as the day warms.

    Example: Rollerballs are precursors to wet loose activity. Keep in mind that terrain traps  like this creek at the base of this steep slope could easily worsen the conseqeuence of a even a small wet loose. 

    Photo: Joe Dellaporta

Avalanche Discussion

Wednesday features milder temperatures than Tuesday with the winds finally dying down. The avalanche trend is slow healing, but it's not yet time to let down your guard.

Several rounds of snow have accumulated 10" of snow (and 2-3" of water equivalent) above the widespread 2/7 crust. In some areas that storm ended with a bit of rime crust near the surface on Monday evening.

Observers in the Timberline area on Tuesday experienced moderate wind transport forming shallow, stubborn slabs up to size 1. The wind transport in this terrain was eroding larger slabs formed on more typical aspects on Monday. Areas further east around Mt Hood Meadows experienced less of the ESE winds and it appears that Monday's slabs did not experience the same erosion. As a result, you can expect some variation in the rates that slabs are healing as you move around the mountain. Some 

Any accumulation is welcome this season, but keep in mind that many travel hazards still exist across the terrain. Rocks, creeks, trees, and other shallowly buried objects are still prominent through the terrain and could easily exacerbate the consequences of an avalanche. 

We could really use the observations as snow stacks up. Let us know what you see by submitting an observation here or on the AvyApp. 

Regioni coperte