Bollettino valanghe

Presidential Range

Mount Washington Avalanche Center
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Pericolo valanghe

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

In sintesi

You could trigger an avalanche today in steep east facing terrain as warm temperatures and rain melt snow. If you find wet, soft snow deeper than your boot-top consider backing off as this has the potential to be a larger avalanche. Warm temperatures and rain are your red flags for unpredictable wet snow avalanches today.

Problemi valanghivi

  • Wet Slabs

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

    Old, stubborn wind slabs have the potential to become increasingly sensitive today with warming temperatures and rain saturating and lubricating the interface between wind slabs. The areas where you are likely to find the largest wind slabs will be on north, east, and south facing steep slopes.

    Frequent use of hand shears will help determine how easily the wet snow will slide on the old snow surface and will be beneficial to understand the sensitivity. Digging down into the snow to see the depth of moisture from rain and melting snow will also help to understand potential size.

Avalanche Discussion

There is uncertainty in today’s forecast around size, sensitivity, and what this mixed precipitation falls as. 

Temperatures seem to be trending warm, so there is the potential for more rain at all elevations. In addition to the rain, last night’s inverted temperatures had ravines above freezing. These warmer temperatures will result in more snow melt and have the potential to increase the sensitivity of the old and stubborn wind slabs. 

Rain on snow events are notoriously difficult to forecast, and part of the discussion this morning centered on if there is enough rain to be a significant factor in potential avalanches today. While there is rain, less than 0.5 of an inch is forecast. Today’s concern comes from the combination of warming and rain as the combo will result in more snow melt. 

Our questions on size came down to not having a pronounced weak layer that we are tracking. In terrain you will find wind slab on top of wind slab on top of another wind slab. There are thin weak layers from changing winds and hardness changes between these slabs, but these have proven to be stubborn and have not been an area of high concern.

Forecasters came to today’s hazard of MODERATE using the Conceptual Model of Avalanche Hazard. Using specific for distribution and stubborn for sensitivity gives a likelihood of possible, considering the potential size for avalanches today puts the hazard solidly in moderate. Careful slope evaluation will be important today.

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