General Bulletin for Monday, April 24, 2017

This bulletin expries at midnight, Wednesday, April 26, 2017.

A General Bulletin is in effect for Tuckerman Ravine until complete melt out in early summer. You will need to do your own snow stability assessments. A new General Bulletin will be issued within 72 hours or when conditions warrant. We are no longer monitoring conditions in Huntington Ravine.

The melt/freeze cycle that creates great spring skiing also stabilizes our snowpack. Deeper instabilities have mostly been eliminated due to a few weeks of this cycle. Heavy skier traffic created large moguls, runnels, and sluff piles under the most popular descents. Areas that have seen less traffic will require good sluff management techniques.

WEATHER: Today, Monday, looks like another good spring-skiing day with temperatures rising above freezing following a night of the snowpack locking up. Tonight, temperatures should drop below freezing again with clouds moving in by Tuesday morning. Over the next few days, a low pressure system developing in the south will move up the eastern seaboard. It looks like Tuesday will see rain develop later in the day and overnight with heavy rain arriving overnight into Wednesday morning. By Thursday, rain totals could equal up to 2” of liquid.

BEWARE OF THE ANNUAL SPRINGTIME HAZARDS

  • Icefall: Most of the ice that history has shown to create problems in the Cutler River Drainage has yet to fall down. Some of the biggest pieces of this reside in the Sluice and threaten the area known as Lunch Rocks. At some point, all the ice still in place will fall down. Warm weather and rain will increase the likelihood of this taking place sooner, both of which are forecast over the next 72 hours. The best tactic for playing it safe in regards to this hazard is to spend as little time as possible below these chunks of ice.
  • Glide cracks and waterfall holes: As the snowpack gradually gives way to gravity and creeps downhill, it pulls away from cliffs and leaves gaps. These gaps are the horizontal cracks that are appearing in the steep terrain, most noticeably in the Lip. These can be surprisingly deep and are a place you don’t want to be. The waterfall hole in the Lip is a unique hazard. If planning on skiing the Lip, place a mental red flag on this hazard during your ascent as it can be hard to identify from above the rollover. In addition to being a large hole that nobody wants to find their self in, this hazard has been the site of wet slab avalanches in the past. Any number of natural events can plug this hole or heavy rain can surge the water flow. If the water is directed into the snowpack rather than behind it, a layer in the snowpack may become lubricated, creating the recipe for a wet slab avalanche.
  • Undermined snow: Meltwater flowing under the snowpack can carve away the snow above, creating thin bridges of snow that can collapse. These are largely found now at the tops of gullies (particularly on south-facing slopes) and in areas that have streams running, like the Little Headwall. Sometimes the sounds of running water can be heard under the snow which is a good indicator of this hazard.
  • Long, sliding falls: Part of what makes spring skiing so great is the melt/freeze cycle creating corn snow. In order for this to occur, the snowpack freezes at night, creating a hard surface that is nearly impossible to self-arrest on. This often causes trouble for those looking to get “just one more run” at the end of the day and trying to ski down when a slope flash freezes due to shade.

The Lion Head Winter Route remains open. The Little Headwall is no longer passable and descending from the Bowl should be done via the hiking trail. The John Sherburne Ski Trail is closed near the bottom. Please respect the rope and cross over to the Tuckerman Ravine Hiking Trail rather than trying to ski rocks and mud.

Please Remember:

  • Safe travel in avalanche terrain requires training and experience. This bulletin 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.
  • For more information contact the Forest Service Snow Rangers, The Mount Washington Volunteer Ski Patrol, the AMC at the Pinkham Notch Visitor Center, or the caretakers at Hermit Lake Shelters.
  • Posted at 8:00am on Monday, April 24, 2017.  A new bulletin will be issued when conditions warrant.

Helon Hoffer, Snow Ranger
USDA Forest Service
White Mountain National Forest
(603) 466-2713

2017-04-24