Bollettino valanghe

Presidential Range

Mount Washington Avalanche Center
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Pericolo valanghe

Sat
Alta quota
2 · Moderato
Limite del bosco
2 · Moderato
Sotto il limite
1 · Debole
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In sintesi

The potential for a larger wet slab avalanche in an isolated area keeps the avalanche danger MODERATE today. Continued warm weather and rain are impacting any remaining dry snow or deeper weak layers and increase the risk of this destructive avalanche type. Loose wet avalanches are also possible. You’ll find challenging travel conditions on trails as firm snow becomes soft and unsupportive. 

 Rain, possibly heavy at times this afternoon, increases many hazards in the mountains. Icefall will occur with greater frequency and glide cracks are opening up due to warm conditions. Rapid melting will also increase stream flow and undermine snow bridges over stream beds. Adjust your travel plans accordingly.

Problemi valanghivi

  • Wet Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Unlikely
    Dimensione
    2

    Prolonged warming, especially the first warming of a previously dry snowpack creates conditions for this avalanche type. Wet snow at the surface with dry snow beneath are easy to identify signals of this potential problem. If you find yourself traveling on steep slopes with wet, slushy snow on top, triggering one of these slides will be possible, particularly when a weak layer or ice crust exists below. Though this avalanche type is rare in our firm, wind-packed snow, it is certainly possible. Continue to use standard safe travel practices in soft, wet snow, such as skiing one at a time with a beacon, shovel and probe, and limiting time spent in avalanche paths. Swollen streams and rivers can also cause large wet slabs to occur when the volume of water flowing exceeds the capacity of the tube created by the snowpack over the streambed.

  • Loose Wet

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

    Rain will create a sloppy surface layer of wet slushy snow where the driest snow once existed. In snow previously undisturbed by skier traffic, these slides will start at a point and fan out as they travel downhill and entrain additional wet snow. Even if they remain small in size, the risk is that the wet snow will move underfoot and possibly carry you. Be careful in steep terrain where falls have consequences. Loose wet avalanches are becoming less of a problem as surface snow becomes consolidated.

Avalanche Discussion

Four inches (10cm) of melting and settlement occurred in the past 24 hours at the Hermit Lake snow plot. Settlement is a good sign that remaining cold dry snow in the snowpack is rounding and avalanche concerns are diminishing. The past weeks melting has led us to continue with moderate avalanche danger messaging due to the low probability but high consequence deep slab avalanches that have occurred here. Cold weather just prior to this warmup cooled the snowpack significantly which slowed the warming and settlement process. The warm conditions and rain have accelerated that process drastically. If you were inclined to dig a deep hole in the snow today, you’d likely find the snow to be 0C in the upper 2’ or so, and possibly to the ground. Wind loaded areas in the range contain a much deeper snowpack with layers of weaker snow or ice crusts still a factor to keep in the back of your mind. These layers are what keep us from moving to low avalanche danger.

New snow is in the forecast for Sunday and will likely bond well to the wet and warm snowpack if we only get a couple inches. Tomorrow’s weather forecast has improved and seems to be a reasonably good day for skiing. If that is your plan, keep the objective hazards created by warming and melting in mind as you choose your route. Glide cracks will be wide enough to trap a leg, moats around rocks will be much wider, rock and icefall will continue to be a threat and undermined snow and swollen rivers increase the chance of drowning if you punch through or fall in. Exiting the Bowl on skis will be dangerous if not impossible depending on rainfall totals.

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Your avalanche, snowpack, or weather observations are extremely valuable to the forecasters at MWAC. Help create a more accurate avalanche forecast by submitting your observations here. 

Listen to the weekly MWAC Outreach Podcast provided by Ski The Whites. Discussions include snowpack information, weekend outlook, and general avalanche related info. 

The Harvard Cabin is open for camping only with no entry allowed inside the cabin. There is no access to the breezeway at HoJos.

Please Remember:

  • Safe travel in avalanche terrain requires training and experience. This forecast is just one tool to help you make your own decisions in avalanche terrain. You control your own risk by choosing where, when, and how you travel.
  • Avalanche danger may change when actual weather differs from the higher summits forecast.

For more information contact the US Forest Service Snow Rangers, AMC visitor services staff at the Pinkham Notch Visitor Center, or the caretakers at Hermit Lake Shelters or seasonally at the Harvard Cabin (generally December 1 through March 31). The Mount Washington Ski Patrol is also available on spring weekends.

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