Avalanche Advisory for Saturday 5-5-2012

This advisory expires at midnight, Saturday 5-5-2012

Tuckerman Ravine has Low avalanche danger. Natural and human triggered avalanches are unlikely except in isolated terrain features. Huntington Ravine is under a General Advisory. You will need to do your own snow stability assessments when using avalanche terrain in Huntington. A danger of falling ice exists, and will persist until it all comes down.   After the weekend we will be moving to a General Advisory for both Ravines which will be valid for up to 3 days per issuance.  Advisories will then discuss general hazards and conditions, but not daily specifics.  You will need to do your own snow stability assessments and daily weather investigation when this begins.

The incoming high pressure is giving the moist air a slow nudge to move out this morning. Yesterday the summit received an inch (2.54cm) of rain from this departing weather maker. Fog and the potential for a shower or two will linger through the a.m. hours before we witness clearing conditions later today.  This limited visibility, created by the fog, will exacerbate the spring hazard problems in the Ravine.  You won’t be able to see ice coming or recognize all the crevasse and terrain issues you should identify before attempting a run.  Take any clearing weather opportunities to give the Ravine’s terrain some focused attention.  Quickly try to determine where ice is hanging, where open holes loom, and where crevasses are located before fog rolls back in.  A plan to stay hard left in the southern end of the Ravine near Left gully will offer the least amount of these objective hazards.  Eventually today, clear visibility will offer you the ability to do a good terrain, crevasse, and hanging ice analysis.  Use this opportunity to evaluate everything you might encounter in your intended run.  As melt out continues an increasing hazard is more terrain features and rocks to collide with in case of a fall.  With these objects being exposed, constrictions being narrower, and run outs ending on 30-40 degree slopes a fall into these immoveable structures is more likely.  So think through your activity, visualize the different potential outcomes if things don’t go as planned and make changes to your travel route appropriately. 

Rain and above freezing temperatures this week has increased the deterioration rate and rotting of any leftover hanging ice, snow bridges near crevasses, and the edges of holes. You won’t be able to see most of these threats in the fog this morning, so your best bet is to avoid the areas where these problems dominate such as in Center Bowl over to the Sluice.  Again, warmth will create ideal conditions for falling ice! For the most continuous snow coverage and the fewest objective hazards, head to Left Gully. From the Chute across to the Sluice you’ll be dealing with increased icefall potential and crevasses. Hillman’s Highway is getting thinner with numerous breaks and rocks poking through.  The lowest portion has become discontinuous due to melt out and undermining.

THE TUCKERMAN RAVINE TRAIL IS CLOSED TO ALL USE FROM LUNCH ROCKS TO THE JUNCTION WITH THE ALPINE GARDEN TRAIL. This includes the Lip area as well as this section of the hiking trail. This annual closure is due to the magnitude of crevasses and undermining that develop in this area during the spring melt-out. A fall in this area would have severe consequences. The trail from Pinkham Notch to the floor of the ravine is open, as is the section above the Ravine from the Alpine Garden Trail junction to the summit. Use an alternate route to circumvent this closed section, such as the commonly used Lion Head trail.  The John Sherburne Ski trail is also closed to all use.

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.  A new advisory will be issued tomorrow.

Christopher Joosen, Snow Ranger
USDA Forest Service, White Mountain National Forest

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