Avalanche Advisory for Saturday, March 10, 2018

Huntington Ravine has CONSDERABLE and MODERATE avalanche danger. Central, Pinnacle, Odell, South and Escape Hatch have Considerable avalanche danger. Dangerous avalanche conditions exist. North, Damnation, and Yale Gullies will have Moderate avalanche danger. Evaluate snow and terrain carefully.

Tuckerman Ravine has CONSIDERABLE and MODERATE avalanche danger. Sluice, Lip, Center Bowl, Chute, Left Gully and Hillman’s Highway have Considerable avalanche danger. Lobster Claw, Right Gully, and Lower Snowfields have Moderate avalanche danger due to a limited snowpack. Heightened avalanche conditions exist on specific terrain features. The Little Headwall has holes in the streambed and thinly covered rocks and ice.

AVALANCHE PROBLEM: Strong wind out of the west and northwest is building wind slabs across our forecast areas. The wind slabs will be largest in areas facing predominately east but will grow large enough to be dangerous in most every forecast area. 4-6” of new snow today will contribute to the growth of these slabs. Moderate rated areas will require careful evaluation and terrain management to avoid triggering a wind slab. Loose dry avalanches will be a problem on and below steep areas. Northern gullies in Huntington melted down quite a bit prior to the recent storms, but a few snowfields remain, so evaluate those areas and protect yourself before committing. The floor of Tuckerman is in the crosshairs of avalanche activity so choose your route carefully if you venture into the bowl. The difference between being struck and buried by a medium versus a large avalanche is only a question of semantics.

WEATHER: A brief weather lull yesterday morning gave way to afternoon snow showers as wind shifted westerly and ramped up to the current 60’s mph on the summit. Overnight, Hermit Lake and the summit recorded approximately 2.5” of new snow. Snowfall continues and is currently heavy at Hermit Lake. Wind will increase a bit while shifting NW before diminishing slightly late tonight. Snowfall today should be around 4” if not slightly more, and we may see another 1-3” tonight. Sunday may bring another trace to 2” of snow as wind continues to decrease. Summit high temperatures in the teens and lows in the single digits are forecast today and tomorrow.

SNOWPACK: The summit picked up 16” of new snow in the past 2 days with 14.5” at Hermit Lake. Most of this snow fell on east winds and was deposited in the flat expanse of the alpine plateau that makes up our fetch zone for wind transport. About half of the new snow from this system fell on light and variable winds which allowed the snow to stick to our slick, refrozen base. Though this icy base has been generally resistant to new snow bonding to it for several weeks now, it seems as if warmer temperatures and lower wind speeds have turned the page. Field work yesterday and ski traffic in Lobster Claw, Right, Sluice, and Hillman’s indicated that the light, dry snow hadn’t developed into slabs, at least not in mid elevation start zones. Steeper areas produced sluffs where snow was sticking in place and evidence of mid-storm sluffing was evident below steep areas.

Please Remember:
• Safe travel in avalanche terrain requires training and experience. This advisory 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.
• Anticipate a changing avalanche danger when actual weather differs from the higher summits forecast. For more information contact the Forest Service Snow Rangers, the AMC at the Pinkham Notch Visitor Center, or the caretakers at Hermit Lake Shelters or Harvard Cabin.
• Posted 7:55 a.m., Saturday, March 10, 2018. A new advisory will be issued tomorrow.

Frank Carus, Lead Snow Ranger
USDA Forest Service
White Mountain National Forest
(603) 466-2713 TTY (603) 466-2856