Lawinenlagebericht

Presidential Range

Mount Washington Avalanche Center
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Lawinengefahr

Mon
Hochgebirge
3 · Erheblich
Waldgrenze
3 · Erheblich
Unterhalb
2 · Mässig
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Veraltet — dieser Lagebericht ist 5 years ago abgelaufen. Du siehst vergangene Verhältnisse, nicht den aktuellen Bericht.

Kernpunkte

Blowing and drifting snow creates CONSIDERABLE avalanche danger today. You could trigger a large slide in exposed terrain where the wind has drifted snow and in wind sheltered locations with softer snow. Natural avalanches are possible at mid elevations, with the Gulf of Slides, Tuckerman Ravine (including the floor of the ravine) and Huntington Ravine as targets for the largest avalanches. Limit or avoid time spent on or below avalanche paths in these locations.

Lawinenprobleme

  • Wind Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Likely
    Größe
    1–2

    Five to seven inches of snow and strong winds are creating a new batch of wind slabs. You’ll find these slabs of drifted snow loaded and cross loaded on multiple aspects. Watch for slabs building quickly today beneath steep pitches of ice and below rock buttresses where snow piles up as it pours down from the steep slope above.  As an example of this,  a crown line from a natural avalanche was visible in the afternoon yesterday below the ice in the center of Tuckerman Ravine. The crown line was around 175 feet wide and 6 to 12” deep. We estimate the avalanche occurred mid to late morning. Wind slabs in wind exposed locations will tend to be more stubborn and overall less likely to avalanche naturally, though still susceptible to a human trigger. 

    Think of today’s avalanche hazard as a continuation of yesterday’s wind slab avalanche problem. Wind slabs formed overnight and today are building on top of freshly formed wind slabs yesterday. From Friday night to this afternoon, we may have as much as 10 inches or more snow available to build large wind slabs two to three feet thick. 

Avalanche Discussion

Observations in the field yesterday were limited by poor visibility. What we did see indicated a fairly widespread covering of new snow, with patches of wind scoured frozen surface from Friday’s re-freeze. Quick hand-shears indicated that the new snow was well bonded, failing within the new snow at a density change. Blowing transporting snow was observed for much of the day, somewhat shutting down in the afternoon. The crown line in Tuckerman Ravine was observed at 3:30pm, and still had sharp lines indicating some recency for when it happened. Given the amount of snow pouring down the headwall, that avalanche likely filled back in, undermining the accuracy of the 6-12” crown line estimation. 

Some level of uncertainty exists with today’s forecast which is driven by total snowfall. The NWS is calling for 3 to 7 inches today with probabilities ranging from 50 to 70%. Quantitatively over 4/10ths of an inch of water is available to make snow. Higher snow totals will build larger slabs, smaller snow totals build smaller slabs. It’s worth mentioning that even if the lesser snow totals are realized, considerable avalanche danger will still be the hazard rating for the day. 

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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. 

Our next free online event is coming up Thursday, March 18 @ 7PM -Women’s Backcountry Talk- A Free Zoom Webinar. Signup is required. 

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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