Avalanche Advisory for Wednesday January 15, 2014

This Advisory expires at midnight.

Tuckerman and Huntington Ravine have MODERATE avalanche danger.  Natural avalanches are unlikely and human triggered avalanches are possible.  Evaluate snow and terrain carefully to identify features of concern.

AVALANCHE PROBLEM: Today’s avalanche problem is Storm Slab and Wind Slab.  New snow fell at upper elevations with prevailing winds from the W and NW causing new slab to be deposited in the Ravines.  Free water is draining from the snowpack substantially diminishing previous Wet Slab concerns.

WEATHER: The summit reported 7″ (17.5cm) of new snow over the past 24 hours with variable winds from the WSW through the W to the N.  Velocities ranged from the singles to about 50mph (80kph).   Lower down the mountain a rain and snow mix prevailed through Tuesday morning creating lower snow totals.  Later in the afternoon this mix changed over to all snow.  Hermit Lake received a total just short of 3 inches (7cm) of snow.  You can presume most start zone elevations, close to 5000ft, received approximately 4″ (10cm).  Winds today will be from the W and increase from a current of 35-40mph (56-64kph) to over 50 (80kph) later. Summit temperatures will climb from 15F to about 20F.

SNOWPACK: As liquid water drains out the bottom of our snowpack, very different things have begun near our snow surfaces.  7″ (17.5cm) of new snow fell on the summit from primarily a W and NW direction, loading into our eastern facing slopes.  Bed surfaces were transitioning from wet and sticky, to hard and slick, as temperatures fell.  Bonding right at the interface should be variable, but would expect new wet snow to have bonded fairly well.  However, a more common failure point could be just above this in the new snow itself.  This is particularly true as new snow transitions from being dense and wet to lighter and dry.  This occurred yesterday as temperatures fell and new precipatation became uniquely dry snow.  Additional loading should be expected later today as winds ramp up, but I wouldn’t anticipate it to be substantial unless wind speeds exceed the forecast. 

Be ready for the danger to be at the upper end of the forecasted rating of Moderate bumping the limits of the definition if loading starts again.  The Lip and the Center Bowl of Tuckerman are two locations that are most likely to flirt with a Considerable rating.  If additional loading occurs we will become concerned about natural avalanches drifting from being unlikely to being more possible.

OTHER HAZARDS:  Expect a lot of water ice on Mt. Washington, right from the moment you get out of your vehicle.  These slick conditions are now hidden by a veneer of new snow. The Tuckerman Trail from Pinkham and the Sherburne Ski Trail has an astounding amount of ice. I recommend traction devices for your feet and poles to help you keep your balance.

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 the Harvard Cabin.Posted 758 a.m. 1-15-2014. A new advisory will be issued tomorrow.

Christopher Joosen, Snow Ranger
USDA Forest Service
White Mountain National Forest
(603) 466-2713 TTY (603) 466-2856

2014-01-15 Print.