Avalanche Advisory for Tuckerman and Huntington Ravines

Tuckerman Ravine and Huntington Ravine have HIGH avalanche danger today. Natural and human triggered avalanches are likely on a variety of slope angles and aspects. Travel in avalanche terrain is not recommended. The only exception to this is the Little Headwall which has Moderate avalanche danger. Natural avalanches are unlikely and human triggered avalanches are possible. Use caution in steep terrain.

Well any other day I’d say I’d be excited by what I’m seeing here at Hermit Lake. There is about 4″ of dense snow on the ground with some deeper drifts and it is currently snowing pretty hard. I’ll take all the snow we can get pretty much any day, but the unfortunate side of this weather event is what’s to come later. Warm air will slowly infiltrate the upper elevations bringing with it a change from snow to mixed precipitation and then rain later. It’s already climbed to 26F (-3C) at the summit and is just above freezing here. The avalanche danger today is going to steadily rise through the day in both ravines. As precipitation changes over to mixed and rain, it will enter the realm of “High.” However, it’s important to remember that the danger will pass through “Considerable” earlier in the day with natural avalanches being possible even prior to any rain. Ultimately, travel in avalanche terrain today is not recommended.

If, after reading the paragraph above, your plans still include heading into either ravine, I’d suggest going back and re-reading the first two paragraphs and asking yourself if spending a wet day with High avalanche danger is really the what you want to do. With heavy rain in the forecast for the next few days, I’m personally planning some quality indoor activities to keep busy. This storm system is a potent one, with up to an inch of water equivalent by midnight tonight and the potential for up to 4″ (10cm) of water equivalent by the time it’s all over late Wednesday. As far as the potential for avalanches goes, two things are in my mind for today. First is the new snow which is falling with forecasted winds to be S shifting W at 50-70mph (80-113kph) early in the day. This would be enough to create instabilities even if the forecast wasn’t for snow changing to rain. The second issue is the older slabs that existed primarily in Tuckerman Ravine and are sitting on top of the rain crust from about a week ago. Dumping rain on these slabs would also increase the avalanche danger. Putting both of these issues together and thinking about what effect the rain will have brings me to my belief that natural avalanches will be taking place today in most areas by the end of today. Some of these will be wet slabs and others may be wet loose snow avalanches, but regardless, I wouldn’t want to be hit with either type.

The warm wet weather over the next few days followed by clear, sunny, and warm weather will do some significant damage to the snow cover across the mountain over the week to come. I would expect the Little Headwall, which already has some open water holes, and the brook leading out of the Ravine to become dangerously undermined by meltwater. Also expect icefall and rockfall hazard to increase as free water melts the bonds between the ice and rocks allowing them to succumb to their natural gravitational urges. Finally, travel off the beaten path may become a nightmare of soggy postholes. Due to the posthole factor it’s probably not a good week to try sledding the Sherburne Ski Trail or bushwacking down the Great Gulf; you’re much better off with flotation on your feet or sticking to well-traveled routes.

The Lion Head Winter Route is open. The John Sherburne Ski Trail is skiable all the way to Pinkham Notch.

Please Remember:
Natural events such as avalanches are impossible to accurately predict 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 higher summits forecast.
For more information, contact the U.S. Forest Service Snow Rangers, the AMC at the Pinkham Notch Visitor Center or Hermit Lake Shelters or the HMC caretaker at the Harvard Cabin. A new avalanche advisory will be issued tomorrow and this advisory expires at midnight.

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

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