USFS Avalanche Bulletin

6:41 a.m. Saturday May 17, 2008

Tuckerman Ravine has LOW avalanche danger. Natural avalanches are very unlikely and human triggered avalanches are unlikely except in isolated pockets. Normal caution is advised. A "GENERAL ADVISORY" is currently in effect for Huntington Ravine. We have finished issuing avalanche advisories using the U.S. 5-scale danger rating system in Huntington for the remainder of the season. You will need to do your own snow stability assessments when using avalanche terrain in this area. A danger of falling ice exists and will persist until it all comes down.

A Happy Queen Victoria holiday weekend to our friends visiting from the north. The weather forecasts continue to keep us on our toes as multiple systems threaten our region over the next several days. The summit is beginning the day with a bit of light snow as temperatures hover around the freezing point. This will keep snow surfaces firm this morning and perhaps through much of the day. As the day continues and warming occurs expect some rain this morning before some partial clearing as the mercury tops out in the high 30's F (4C). A bit of sun is actually possible before it turns for the worse again overnight and tomorrow. Although precipitation will be light, showers are anticipated to be on and off over the next several days. We still expect 0.3" (.75cm) of moisture for the weekend.

Left Gully and Hillman's Highway continue to provide the best riding and skiing with top to bottom coverage. Crevasses and undermining have started to pop up in these areas but nothing like the rest of the Bowl. These two locations are also not immune to icefall hazard but it is much less of a concern than the rest of the Ravine. Check out the photos page on our website to see some images from yesterday.

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 AND THE SECTION OF THE HIKING TRAIL FROM THE FLOOR OF THE RAVINE THROUGH THE TOP OF THE HEADWALL. Only this section of the trail is closed. This section is closed annually 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.

ICEFALL remains a significant hazard in Tuckerman Ravine. Large chunks still remain above Lunch Rocks in the Sluice and in the center Headwall, though no area is completely immune to icefall. A number of people had close encounters with icefall recently. Always be aware of what is above you and have a plan in mind for what you will do if icefall occurs.

CREVASSES exist in many areas and rival icefall as the primary concern for visitors. Although the Lip, Headwall, and upper Bowl have the greatest concentration of crevasses, most other areas have begun developing fissures as well. These may be very difficult to see from above so remember to always climb up what you plan on descending to allow you to assess the hazards at a more leisurely pace. Also be on the lookout for [UNDERMINED AND COLLAPSING SNOW around crevasses as well as water channels.

The John Sherburne Ski Trail is finally closed after having one it's longest seasons in a very long time. It is not designed for foot traffic so you will need to hike down on the Tuckerman Ravine trail from Hermit Lake to Pinkham.

The Lion Head Summer Trail is open. This trail traverses a steep snow-covered slope just above treeline. A slip here has the potential to result in a long sliding fall. It is important to remember that the "trail" is buried under snow and you need some mountaineering skills to use this trail safely. Therefore we recommend bringing an ice axe and crampons for travel through this snow section.

	*** PLEASE REMEMBER ***
	*** It is impossible to accurately predict natural events, such as avalanches, in every instance. This Advisory is one tool to help you make your own decisions in avalanche terrain. It should be used along with safe travel techniques, snow stability assessments, an understanding of weather's effect on the snowpack, and proficiency in avalanche rescue. *** You should obtain the latest weather forecast before heading into the mountains. Anticipate a changing avalanche danger when actual weather differs from the National Weather Service forecast. *** For more information, contact the U.S. Forest Service Snow Rangers, the AMC caretakers at Hermit Lake, or the AMC at Pinkham Notch Visitor Center. This advisory will expire at midnight.

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

	Avalanche Bulletin
	Tuckerman Ravine The Lip Hillman's Highway Lower Snowfields Left Gully Right Gully Little Headwall The Bowl Headwall Huntington Ravine Pinnacle Gully Damnation Gully Yale Gully Escape Hatch South Gully Central Gully Odell's Gully North Gully

U.S. Avalanche Danger Scale

LOW: Natural avalanches very unlikely. Human triggered avalanches unlikely. Generally stable snow. Isolated areas of instability. Travel is generally safe. Normal caution advised.

MODERATE: Natural avalanches unlikely. Human triggered avalanches possible. Unstable slabs possible on steep terrain. Use caution in steeper terrain on certain aspects (defined in accompanying statement).

CONSIDERABLE: Natural avalanches possible. Human triggered avalanches probable. Unstable slabs probable on steep terrain. Be increasingly cautious in steeper terrain.

HIGH: Natural and human triggered avalanches likely. Unstable slabs likely on a variety of aspects and slope angles. Travel in avalanche terrain is not recommended. Safest travel on windward ridges of lower angle slopes without steeper terrain above.

EXTREME: Widespread natural or human triggered avalanches certain. Extremely unstable slabs certain on most aspects and slope angles. Large destructive avalanches possible. Travel in avalanche terrain should be avoided and travel confined to low angle terrain well away from avalanche path run-outs.