General Advisory for Tuckerman and Huntington Ravines

This advisory expires at 12:00 midnight, Thursday, April 30, 2014.

Tuckerman and Huntington Ravines are under a late season General Avalanche Advisory. You will need to do your own snow stability assessments when traveling in avalanche terrain. General Advisories are valid for no more than three days, but may be updated earlier as conditions warrant.

This is a late season General Advisory, which is different from advisories using the 5-scale danger rating system. It’s important for you to understand that there may be unstable snow while a GA is in effect. Instabilities may come in many forms, such as wind slab, wet slab, loose wet snow, etc. We most often use GAs late in the season after the snowpack has stabilized to the point where day-to-day weather changes are not going to drastically affect snow stability. But remember, you are ultimately responsible for making your own assessments of snow stability when using avalanche terrain.

This upcoming week we expect to see rain and generally unsettled weather over the mountain. Even in a springtime snowpack, rain can exacerbate a lot of problems. In addition to the annual spring hazards listed below, a heavy rain event can cause large destructive wet slab avalanches, particularly in the Lip. At this time of year, I would not personally recommend traveling into Tuckerman during a heavy rain event, due to the variety and magnitude of hazards present.

FALLING ICE is a very dangerous situation. The largest ice looms in the Sluice above Lunch Rocks, in the Center Bowl of Tuckerman, and throughout much of Huntington. Other areas pose this threat as well, though to a lesser extent. The best advice we can give is to not spend time underneath areas where ice may fall. Large rocks may provide some cover, but they have proven themselves in the past to be inadequate shields for people hiding behind them. Lunch Rocks is a hazardous location when icefall is a possibility!

CREVASSES AND WATERFALL HOLES are another potentially lethal hazard. Each season these form in many areas, the worst are in the Sluice, Lip, and Center Bowl. Many of these holes follow stream courses under the snowpack with icy water spraying around. We anticipate these hazards to be increasing in magnitude throughout this week.

UNDERMINED SNOW is related to the hazard above. It occurs when streams have eroded away the snowpack from below, but left behind a bridge of snow. This bridge can collapse without warning under your weight, bringing you into the icy stream below. Give wide berth to areas that have already collapsed or show signs of sagging or cracking.

LONG SLIDING FALLS are probably the #1 cause of injury each spring. Cold temperatures cause the soft corn snow to refreeze into a slick and solid mass of ice. We always recommend an ice axe and crampons for travel in steep terrain. You may not need them always, but if the unexpected happens these tools, and the ability to use them effectively, can save you from serious injury or death.

The Lion Head Winter Route is still open. The bottom half of the John Sherburne Ski Trail is closed. Please cross over to the hiking trail at the closure rope and hike the rest of the way down to Pinkham.

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.
  • Posted 7:15 a.m. April 29, 2014. A new advisory will be issued Friday, May 2.

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

2014-04-29 General Advisory

Avalanche Advisory for Monday, April 28, 2014

This advisory expires at 12:00 midnight.

Tuckerman Ravine has Low avalanche danger. Natural and human triggered avalanches are unlikely. Be prepared for increasing avalanche hazard if snow falls heavier than forecast.

Huntington Ravine is under a General Advisory. You will need to do your own snow stability assessments when traveling in avalanche terrain in Huntington. A danger of falling ice exists, and will persist until it all comes down.

AVALANCHE PROBLEM: Generally, snow stability in the ravine will be good today. There may be opportunities for loose wet sluffs to be a problem. Areas that see a lot of skier traffic will be less affected by this issue; get off the beaten track and you may see more of it.

WEATHER: 3” (7.8cm) of new snow fell Saturday through daybreak Sunday, this was followed by just a trace of snow during the day yesterday (reports were that it rained steadily in the valley, but all we saw was snow). Today will be cloudy, with the potential for fog to drop low enough into the ravines to obscure the visibility. Temperatures should warm above the freezing mark in the ravines, while winds will be on the light side for Washington. All in all, it won’t be too shabby of a day if you don’t mind the clouds.

SNOWPACK: Yesterday around noon, temperatures rose about 5 degrees in a short amount of time, bringing temperatures at ravine elevations above freezing. This warming helped moisten the new snow. After subsequent refreezing last night, the thin new layer is likely to be well-adhered to the older surfaces below. Rising temperatures today should allow surfaces to soften again. However, cloud cover may make this slower to happen than if it were a sunny day.

OTHER HAZARDS: ICEFALL is a possibility today. Not much ice has fallen yet this season, which means there is still a large amount of ice up in the headwall and in the Sluice above Lunch Rocks waiting to come crashing down. Don’t spend any more time than you need to in areas exposed to icefall hazard, such as at Lunch Rocks.

CREVASSES have been late in emerging this season. I expect that this week we will begin to see these cracks creep up to the surface. Remember that what you see at the surface is often much smaller than the hole beneath the snow. Approach crevasse prone areas (e.g. the Lip) with caution and choose your route carefully, or avoid these locations altogether.

The Lion Head Winter Route is still open. This is a steep icy trail. An ice axe, crampons, and the ability to use these tools effectively are highly recommended. Lightweight trail crampons lose their effectiveness in steep terrain!

The John Sherburne Ski Trail is open to about 1 mile from Pinkham and closed below this point. Expect lots of bare patches, icy sections, and enormous bumps throughout the trail.

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 or the AMC caretakers at Hermit Lake or staff at Pinkham Notch Visitor Center.
  • Posted 6:55a.m. 4-28-2014. A new advisory will be issued tomorrow.

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

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