Latest avalanche advisory for Mount Washington’s Cutler River Drainage – Tuckerman and Huntington Ravines

Avalanche Advisory for Saturday, February 24, 2018

Huntington Ravine and Tuckerman Ravines have LOW avalanche danger. All forecast areas have Low avalanche danger. Generally safe avalanche conditions. Watch for unstable snow on specific terrain features. The Little Headwall is an open stream and is not a viable route out of Tuckerman Ravine.

AVALANCHE PROBLEM: Small and isolated pockets of new wind slab may exist in our terrain. Minimal new snow overnight has been heavily affected by westerly wind. Most of our terrain remains a hard, refrozen snow surface where avalanches will not be your primary concern. This icy and particularly slippery snow will require appropriate traction devices in any terrain. This means crampons and ice axes on snow slopes and steep trails and microspikes elsewhere. Consequences of a sliding fall on our hard, icy snow remain high, with numerous rocks and other hazards exposed below steep terrain. Appropriate terrain choices and travel skills will help you avoid a high speed fall that could result in serious injury or worse.

 WEATHER: Yesterday brought 0.30 inches of water to the summit which fell mostly as rain, freezing rain, and sleet. Only 0.5 inches of snow was recorded. The little snow we received fell on SW wind that shifted W and ramped up overnight to the current gusts over 100 mph. Temperatures hovered just above freezing at Hermit Lake and just below freezing on the summit late yesterday and last night. It has now turned colder, with a steady summit temperature around 20F forecast today and likely a few degrees warmer in our terrain. Wind and summit fog should decrease through the day. A system moving in late tonight will bring snow and possibly mixed precipitation tomorrow as summit temperatures approach the high 20’s F. This storm which is forecast to become increasingly warm could bring over 6” of new snow, though timing of the forecast changeover to mixed precipitation will ultimately determine new snow accumulation.

SNOWPACK: The mixed bag of precipitation late yesterday and overnight largely fell as rain, freezing rain, and sleet, all of which refroze and now contribute to our hard and icy snow surface. The limited new snow mixed in this storm was heavily transported by wind, and at best amounted to quite small wind slabs that pose little danger to travelers in the alpine. Potential for a long sliding fall on our largely hard and slick snow surface should guide your terrain choices today. Realize that preventing such a fall is essential, as arresting one would be very difficult. Crampons, ice axes, and your ability to use them are essential on snow slopes. Clear skies and sun may briefly and slightly soften snow on south-facing aspects this afternoon, but this window of anything but rock-hard snow will be brief if it happens at all.

 The John Sherburne Ski Trail holds icy snow with patches of water ice and bare ground.

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 Harvard Cabin.
• Posted 7:45 a.m., Saturday, February 24, 2018. A new advisory will be issued tomorrow.

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

2018-2-24

Avalanche Advisory for Friday, February 23, 2018

This advisory expires at midnight.

Huntington and Tuckerman Ravine will have LOW avalanche danger today. Generally safe avalanche conditions exist for all forecast areas.

AVALANCHE PROBLEM: This morning, there is no avalanche problem. Avalanche terrain consists of refrozen snow that with its hard, icy surface, will require the use of crampons and an ice axe to navigate safely. Long sliding falls are currently the greatest danger. Up to 2” of snow is forecast on increasing SW wind in the afternoon and will create areas of wind slab. If we receive the upper end of the forecast snow total, areas in the lee of SW and W wind may exceed the current Low rating.  Be aware of this in Hillman’s Highway, Left Gully and the Chute in Tuckerman as well as Escape Hatch, South and Odell in Huntington. Warming temperatures late may mix sleet and freezing rain into this snow, adding a wet layer to the snow surface. Travelers out late in the day should keep an eye on the sky and be prepared to re-evaluate plans if we receive the upper end of forecast totals.

WEATHER: Yesterday consisted of scattered clouds and a mild NW wind. Temperatures at Hermit Lake and the Summit both saw a maximum in the low 20sF. Lingering high pressure this morning will keep skies largely clear with mild winds and temperatures in the 20sF. Incoming low pressure this afternoon will allow fog to develop on the summits. Current W wind of 25mph will shift to the SW this morning and steadily increase through the day to 50-70mph. Once darkness arrives, the wind will shift to the W and eventually NW by midnight. Snow showers are likely before the temperature rises enough for a transition to mixed precipitation. The amount of liquid precip should remain low, with up to 0.15” by midnight. If we receive the high end of forecast precipitation, we may see 2” of snow.

SNOWPACK: Record-setting temperatures Tuesday and Wednesday were followed by a freeze Wednesday night. This has stabilized our snowpack and created icy surfaces in avalanche terrain. If you venture off-trail in the woods, it may still be possible to post-hole in areas, though above-treeline surfaces should remain solid. Traction is necessary even on flat trails at the moment. The Little Headwall is now an open river and no longer an option for skiing out of Tuckerman Ravine. The Sherburne has stretches of bare ground and water ice. Be prepared to remove your skis at times on the way down.

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 Harvard Cabin.
• Posted 8:10 a.m., Friday, February 23, 2018. A new advisory will be issued tomorrow.

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

2018-02-23