Jan 262015
 

This advisory expires tonight at 12:00 midnight.

Tuckerman Ravine has Moderate and Low avalanche danger. Lobster Claw, Right Gully, the Sluice, Lip, Center Bowl, and Chute have Moderate avalanche danger. Natural avalanches are unlikely and human triggered avalanches are possible. Left Gully, Hillman’s Highway, the Lower Snowfields, and Little Headwall have Low avalanche danger. Natural and human triggered avalanches are unlikely.

All forecast areas of Huntington Ravine have Low avalanche danger. Natural and human triggered avalanches are unlikely. Watch for unstable snow in isolated terrain features.

AVALANCHE PROBLEM: In Tuckerman Ravine, you’ll be dealing with large snowfields with thick wind slab as your avalanche problem today. Huntington is mostly scoured of new snow, with the exceptions of down near the approaches and lower sections of Central, Pinnacle, and Odell. In these areas you may find softer dry loose deposits mixed with wind slab. In Tuckerman, the slabs will have a lot of strength in many locations, but remember that you only need to find a hidden weak spot and you could easily trigger a sizeable avalanche.

WEATHER: It’s pretty hard to ignore the hyperbole around the “historic” winter storm that is poised “bury the Northeast from New Jersey to Maine.” This will begin tonight, but won’t be affecting today’s avalanche issues. Later today, I’ll take a look at this storm in more detail in The Pit on our website. But for today, you will want to know that Mt. Washington received just under 4” (10cm) of new snow in the past 3 days at the upper elevations. Down at Hermit Lake, we received less than half of this amount. Yesterday winds blew from the NW at 60-90mph throughout much of the day before diminishing overnight. Today begins with gorgeous calm, cold weather and clear skies…a perfectly cliché calm before the storm.

SNOWPACK: As mentioned, Huntington was mostly scoured of the new snow, leaving behind a lot of old surface including some old, gray crust in some spots. Areas at the base of Central, Pinnacle, and Odell have caught our eye as where you might find isolated pockets of unstable snow. Often strong winds carry snow lower down into the terrain and sluffing contributes to this as well. If you’re alert, you should be able to avoid or manage these issues without too much difficulty.

In Tuckerman Ravine, Hillman’s and Left Gully are also mostly scoured. The biggest issues in Tuckerman are found in locations strongly protected from NW winds, such as the Sluice and Lip. The crown line left behind from Tuesday’s avalanche in the Sluice and Lip has been fully reloaded. Looking farther left, the Center Bowl and Chute show lesser amounts of loading, but are not scoured as Left Gully is. Expect slabs in this area to be thick and reasonably strong, but to hold the potential for a large avalanche if they were to be triggered.

We continue to hear reports of just how bad the skiing is on the Sherburne. I drove down it yesterday and can confirm these reports to be true. Let’s hope there is enough snow to bury the current ice layer so deeply that it doesn’t reappear until May. The Lion Head Winter Route remains closed; use the summertime Lion Head Trail if going this way. Trees on the traverse section at treeline are still standing tall and proud, so we’ll see how the coming storm develops this avalanche path and reassess it later.

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.
  • Posted 8:20 a.m. January 26, 2015. 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

2015-01-26

 Posted by at 8:23 am
Jan 252015
 

This advisory expires tonight at 12:00 midnight.

All forecast areas of Tuckerman Ravine and Huntington Ravine have CONSIDERABLE avalanche danger. Dangerous avalanche conditions exist. Natural avalanches are possible and human triggered avalanches are likely. Careful snowpack evaluation, cautious route finding, and conservative decision making are essential. The only exception to this is the Little Headwall in Tuckerman which has Moderate danger. Natural avalanches are unlikely and human triggered avalanches are possible in this forecast area.

AVALANCHE PROBLEM: Wind slab will be developing today, causing avalanche danger to be on the rise in all forecast areas. Some locations will be directly loaded from blowing snow being deposited on strongly sheltered slopes. The areas of greatest concern include the Sluice, Lip, and Center Bowl in Tuckerman as well as Central and Pinnacle Gullies of Huntington. Other adjacent locations will also have new slab development, and although not quite as quickly, the avalanche danger will rise in these areas to the Considerable level.

WEATHER: Yesterday evening Mt. Washington picked up some more new snow totaling just less than 3” (7.5cm) by 6am. Additional snow will continue through this morning. When it’s all said and done, 4-6” of new snow will be available for 65-85mph (105-139kph) NW winds to pick up and deliver to the eastern-facing ravines. You can expect falling temperatures through today along with the possibility of clearing out of the fog later. Until then, visibility will be quite poor due to fog and blowing snow.

SNOWPACK: Your primary focus on the snowpack today should be on the upper layer of slab that is developing. Some deeper issues may be of interest to serious snow geeks, but from the recreational perspective you can keep your attention at the surface and in the air above. Winds at 65-85mph have the capacity to pick up and move snow that has fallen far away from the ravines. Even if this morning’s forecasted 2-4” comes in at the lower end, we expect all areas to be loaded to a point where we have concerns of naturally triggered avalanches. If we do get the upper end of forecasted snowfall, in some locations we might be moving from naturally triggered avalanches being “possible” toward “likely.” Ultimately, today you should know that there are concerns about stability today, particularly with regards to human triggered avalanches if people are out in the avalanche start zones.

If you’re expecting boot-deep powder on the Sherburne, you’ll have a disappointing day. There may be drifts where it’s gotten that deep, but from Hermit Lake down to Pinkham there is less new snow that up above treeline.

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.
  • Posted 8:20 a.m. January 25, 2015. 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

2015-01-25

 Posted by at 8:17 am