Avalanche Advisory for Tuckerman and Huntington Ravines

Posted 8:23a.m., Monday, January 31, 2011

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

Huntington Ravine: All forecast areas have Moderate avalanche danger. Natural avalanches are unlikely and human triggered avalanches are possible. The only exception to this rating is the Escape Hatch which has Low avalanche danger. Natural and human triggered avalanches are unlikely in this area.

I could get used to these clear blue sky mornings, but I don’t think I’ll ever get used to the -5F temperatures we currently have at Hermit Lake. The clear skies are providing ample visual clues as to what transpired in the ravines yesterday and overnight, and the morning sunshine is illuminating the plumes of blowing snow over areas such as Hillman’s Highway and the Lip. While the most significant loading and peak instability are probably behind us at this time, this morning’s 65mph (105kph) NW winds are providing sufficient wind loading to keep avalanche danger ratings elevated today. We do expect wind speeds to diminish slightly, but so far this morning they haven’t shown any signs of doing so. Additionally, cold temperatures will limit the amount of solar gain that can take place, so newly developed slabs will stay elastic, snappy, and reactive to additional loads. In Tuckerman, the areas of most concern are from the Sluice through the Center Bowl. A notable feature of this area is the absence of recent avalanche activity, as well as the low drifting snow that continues to pour down through these locations. Hillman’s also has a significant snow plume blowing over the top, which keeps the threat of natural avalanche activity present. On the northern side of Tuckerman, recent avalanche activity has helped remove some of the threatening snow from the gullies. With that said, understand that not every bit of unstable slab was cleaned out, and some reloading has occurred. These areas are at the upper end of the Moderate rating. Should you find yourself traveling in these areas you should expect new slabs to be reactive to human triggering.

Huntington Ravine also has a few “head’s up” locations, but on the whole this ravine presents a lesser avalanche danger than Tuckerman. We do believe it would be possible for you to trigger an avalanche in several locations, hence the Moderate rating. The bottom of South Gully, above the ice bulge in Central, and above the ice in Odell are just a few examples of where you can find potentially unstable snow. In the northern gullies it is the lower to middle sections that will pose the greatest threat.

A couple other noteworthy thoughts for this morning come to mind. First, the Escape Hatch and Little Headwall are both posted at Low avalanche danger. I personally don’t think either of these locations are quite ready to be used as descent routes. The Escape Hatch would be an epic bushwack, and the Little Headwall still has some open water and ice bulges. Remember, it’s still recovering from a 100% meltout at the start of January. Second, we have a hefty winter storm heading our way for Wednesday. I’ll go out on a limb and predict over a foot of snow, maybe 14-16″ by Thursday morning–but I’m not a meteorologist so don’t blame me when we only get a dusting! Hire the neighborhood kids to shovel your driveway and book your hotel room for Tuesday night so you don’t need to make the drive in the middle of the storm.

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.
  • This advisory expires at midnight. 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

Printable Advisory

Avalanche Advisory for Tuckerman and Huntington Ravines

Posted 8:23a.m., Sunday, January 30, 2011

Tuckerman and Huntington ravines will have CONSIDERABLE avalanche danger today. Natural avalanches are possible and human-triggered avalanches are likely.  The only exception to this rating is the Little Headwall in Tuckerman which has Low avalanche danger.  Natural and human-triggered avalanches are unlikely in this area today.

This morning’s alpenglow was like a dream.  The tops of the ravines were ablaze in sunlight, barely a cloud was in the sky and the windless conditions made you forget that the mercury was still sitting below 0F at the summit.  Everything continues to appear so calm and peaceful but you just wait eight hours!  A passing disturbance has already started to cause the clouds to thicken and snow flurries to develop.  Maybe an inch (2.5cm) of new snow will fall before a trailing cold front pushes in and things begin to get interesting.  When this happens we’ll see an increase in winds as they blow out of the W at speeds up to 50mph (81kph).  These weather variables by themselves are probably leaving you scratching your head and wondering how the avalanche danger ratings have climbed in all areas today.  All you need to do in order to answer your own question is go kick around the Alpine Garden or Bigelow Lawn.  Since Thursday the Observatory has recorded just under 4” (10cm) of snow with an overall density of 3.1%.  Fluff like this isn’t very well designed for typical Mt Washington winds but the readings from the summit anemometer have been lower than normal since the low density snow began falling.  It hasn’t gusted over 50mph (81kph) since Thursday morning and yesterday’s average wind speed was a mere 13mph (21kph)!!!  During this period the blanket of champagne powder has lain waiting for the wind to set its travel plans in motion and today looks to be the day.  Wind-transported snow should begin to form soft slabs high in starting zones during the midday before higher speeds allow deposition farther down in the ravines late in the day.  Although they’re supposed to stay out of the W for the daylight hours you’ll want to keep an eye on their direction as a shift to the NW is expected this evening.  A shift to the NW would likely produce even greater levels of wind transport. 

Starting the day out we’re in a mix of Moderate and Low avalanche danger but expecting to climb the scale as we move into the second half of the day.  Windslab development will first take place atop unconsolidated light density snow thus creating the the “upside-down snowpack” that we are taught to keep an eye out for.  Because 3% snow has very little strength we expect to see small avalanches in many areas as winds ramp up.  After one avalanche cycle wraps up in an area I would expect reloading of the same slope to occur with development of thicker and more dangerous windslab. This is most likely in areas with E aspects such as the Center Bowl in Tucks and the gullies from Odell to Central in Huntington.  The areas on the periphery with N and S aspects will see cross-loading occur and we believe natural avalanches are possible late in the day.  Some of these areas like Huntington’s Escape Hatch are far less of a concern than say the top of Pinnacle but the snow densities and forecasted wind may still cause avalanche activity to occur.

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.
  • This advisory expires at midnight. A new advisory will be issued tomorrow.

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

Printable Advisory