Bollettino valanghe

Central Cascades

Central Oregon Avalanche Center
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Pericolo valanghe

Fri
Alta quota
3 · Marcato
Limite del bosco
3 · Marcato
Sotto il limite
2 · Moderato
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In sintesi

On Thursday you can trigger avalanches in wind drifted snow and in the new storm snow. Avalanches can happen at all elevations where there is enough snow to slide. Avalanches can be large, especially in areas where slides release in deep deposits of wind drifted snow. Minimize your exposure by sticking to lower angle terrain less than 30 degrees steep. 

 

Problemi valanghivi

  • Storm Slabs

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

    The size of this problem will depend on how much snow actually falls overnight and on Thursday. If we get the upper end of the snow forecast, storm slab avalanches will have the potential to be large. Steep, convex, and unsupported terrain are the places you are more likely to trigger a storm slab. Using small test slopes to check for the reactivity of storm slabs is a good strategy. If you see cracking in the slab or recent avalanches recognize these as signs of unstable snow. 

    Archive Photo: Gabriel Coler

    Small storm slab avalanche on a convex roll. 

  • Wind Slabs

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

    With the return of winter like weather, wind slabs are back. Do not get complacent with the wind slab problem. They can be tricky to gauge because subtle changes in slope aspect and wind direction can cause slopes to load differently. Some pieces of terrain may have very little wind loading while other nearby slopes have significant slabs.

    Below ridges and  high points are common places where wind slabs form. Wind moving snow across a slope can fill in gully features and is also something to watch for especially in steep terrain. Use your evaluation skills including checking out low angle terrain or small test slopes to check depth and reactivity of wind slabs. If you see cracking in the slab or recent avalanches, these are good indicators of unstable snow.

    Open slopes below treeline may also have wind slabs. Areas of dead or sparse trees, exposed ridges, and clearings can have enough of a wind effect to get wind slab formation. 

    Archive Photo: Gabriel Coler

    Small wind slab avalanche on a lee slope below ridgetop. 

Avalanche Discussion

Be aware of where you are in relation to terrain traps. With our current low snowpack, there are many exposed rocks, cliffs, logs, etc. Getting caught by an avalanche and pushed into terrain traps can increase the consequence.

Recently formed cornices will be fragile and easily broken. Avoid stepping out onto a cornice. They can break under the weight of a person and can lead to a fall onto the slope below. Be cautious when approaching ridge tops, especially if you don't have a good vantage to see if a cornice is present or not. Cornice breaks can also trigger wind slab avalanches on lee slopes. 

Regioni coperte