Avalanche forecast

Presidential Range

Mount Washington Avalanche Center
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Avalanche danger

Thu
Alpine
1 · Low
Treeline
1 · Low
Below
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Highlights

Wet snow avalanches are possible today on North through East through South aspects.  These avalanches will be small in size but widely distributed in the terrain.  To avoid these avalanches, travel on low angle slopes.  If venturing into steeper terrain, watch for your boots sinking deeply into the snowpack with a slush layer beneath to indicate the avalanche hazard.

Avalanche problems

  • Loose Wet

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–1.5

    Small wet loose avalanches are possible on North through East through South facing aspects at middle and upper elevations.  You will be able to identify this avalanche problem with boot penetration near or above boot top and wet snow beneath.  As temperatures continue to warm today, melt water will collect on the old Icy bed surface beneath the newer snow; lubricating the snowpack and giving it the potential to slide.  These Wet Loose avalanches will move slowly but will set up similar to cement when it comes to rest.  Caution should be used if you are seeing “sluffs” or “roller ball” activity while traveling in steep terrain today. 

  • Wet Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely
    Size
    1–1.5

    Slabs of wet, consolidated snow may be found throughout the eastern terrain at middle and upper elevations.  Because of the lack of visibility over the past several days, there is uncertainty whether this avalanche hazard exists.  However, if you notice snow becoming more supportive under your feet, you have likely found a slab.  These could be small in size, but still large enough to carry you into other hazardous terrain like rocks and cliffs.  Assessing boot penetration as you travel will help you identify this hazard.

Avalanche Discussion

Yesterday Tuckerman Ravine was in the clouds with temperatures around 40 degrees, receiving just shy of a quarter inch of rain before tapering off in the afternoon.  The summit hovered around the freezing mark for most of the day with some freezing rain, rain and a trace of snow reported.  At mid-elevations the snowpack was wet, heavy and had the classic “mash potato” consistency.  In snow tests, this presented as one cohesive layer of snow on top of the old bed surface that was stubborn to trigger in hand shear and column tests.  Overall the snowpack was gaining stability as it warmed.

Overnight temperatures remained above freezing at Hermit Lake and the snowpack did not fully refreeze at lower elevations, but refroze overnight on the summit.  Today temperatures will rise to above freezing early and the summit of Mount Washington will see temperatures close to 40 degrees by mid afternoon.  Any areas that did not warm and consolidate yesterday will be doing so today.

The concern for today's avalanche hazard comes from the new snow layer from Sunday which is widely distributed on eastern aspects.  This layer can be up to 1½ feet deep and has been warming over the past 48 hours.  The continued warming today will assist in bonding the snow to the old bed surface, but does not rule out the possibility of wet avalanches.   

Also, in the last 24 hours there has been very little visibility in Tuckerman Ravine, and because of this, there is uncertainty about our second Wet Slab avalanche problem.  It is possible to find isolated, wet slabs that have not warmed enough to stabilize.  They could be found on wind protected, eastern slopes that stayed cooler over the past couple days.  These slabs will have less boot penetration than the snow lower in elevation which will be a good indicator that you have found this potential avalanche problem.  As temperatures continue to warm the snowpack throughout the day, the stability of these slabs will be uncertain and therefore continued assessment of the snow should be used while traveling in steep terrain.

Remember that significant melting has occurred over the last few days, bringing springtime objective hazards to the forefront. If you are in the mountains today be watching for: 

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  • The John Sherburne Ski Trail is closed at the third cut-over 3/4 down from the top.  Please cross over to the Tuckerman Ravine trail at the yellow rope and walk down the hiking trail.
  • The Harvard Cabin is closed for the season.
  • The Lion Head Summer Trail remains closed for the season due to avalanche risk. The Lion Head Winter Route is open.

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