Apr 162014
 

Tuckerman Ravine has Low avalanche danger. Natural and human triggered avalanches are unlikely.

Huntington Ravine is under a General Advisory. You will need to do your own snow stability assessments when traveling in avalanche terrain in Huntington. A danger of falling ice exists, and will persist until it all comes down.

AVALANCHE PROBLEM: Plunging temperatures overnight are freezing our snow pack and beginning to lock up free water. A small amount of new snow (<1″) with continued upslope snow may create small pockets of unstable Wind Slab in lee areasThis morning, high winds are likely scouring high start zones and depositing snow lower in the Ravines. As winds slow later, look for the potential for wind slab development in higher start zones. Monitor the amount of new snow fall today and anticipate a potentially growing hazard, particularly if more upslope snow falls than is forecast.

WEATHER: The summit temperature graph was bearish last night, to say the least. Temperatures dropped to -2F (-19C) from a steady 40F (4C) last night at 6pm. Cold frontal passages like the one we are experiencing often spawn upslope snow shower activity on the mountain, though the Obs is only calling for a trace to one inch (2.5cm) of new snow today. Winds are blowing pretty steadily around 90 mph (115 kph) this morning. NWS point forecast is for 115 mph (185 kph) gusts this morning. Either way, it is pretty darn windy out. NW winds should fall off to 30-45 mph (50-70 kph) by sunset with clearing skies and temperatures rebounding a bit to the mid-single digits F (+/-  -15C).

SNOWPACK: To sum it up, hard and icy everywhere and undermined in many areas. If weak layers deep in the snowpack remain intact after the warm spell, they will be thoroughly bridged over by a icy skin of frozen slush and cold hard slabs of melt forms in the upper layers. The 2.18″ of rain that fell in the past 36 hours have opened waterfall holes and crevasses and undermined snow bridges covering water channels. Despite the cold, water is still flowing and continuing this process so if you venture into the Ravines be aware of the potential for punching through into these voids which can be surprisingly deep. Some thin areas in Right Gully and Sluice and areas over high volume water courses like the Lip and Center Bowl could collapse. The Little Headwall is now a waterfall. The Lip/Center Bowl waterfall hole and a crevasse along the base of the ice opened up on Monday and likely grew yesterday. I wouldn’t be surprised to see a slot lower near the top of the Open Book when visibility improves later today.

OTHER HAZARDS:  Today, we are standing at the busy intersection of winter and spring hazards. Cold temps and high winds coupled with open waterfall holes and icy trails make travel in the mountains challenging. Recent rain and warm weather really melted out snow spanning streams like the one that flows out of Tuckerman. With our deep snowpack, the distance from snow surface to rushing streambed below could make it difficult to climb out of some of the holes.

Micro-spikes and other creeper style traction devices may be helpful on some lower angle trails, but they do not provide the security of crampons. Be prepared to handle steep, firm snow and fast, icy surfaces. A fall on steep terrain today would be next to impossible to self-arrest. Don’t fall today, especially above a crevasse or streambed.

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.
  • Posted 7:55 a.m. 4-16-2014. A new advisory will be issued tomorrow.

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

2014-04-16 Print friendly

Apr 152014
 

This advisory expires at 12:00 midnight.

Tuckerman Ravine has Considerable avalanche danger. Natural avalanches are possible and human triggered avalanches are likely. Dangerous avalanche conditions will exist after rainfall begins. Careful snowpack assessment, cautious route finding and conservative decision making are essential.

Huntington Ravine is under a General Advisory. You will need to do your own snow stability assessments when traveling in avalanche terrain in Huntington. A danger of falling ice exists, and will persist until it all comes down.

AVALANCHE PROBLEM: Potentially heavy rain today will create the potential for Wet Slab avalanches. The largest of these would be most likely to occur in the Sluice, Lip and Center Bowl area if the larger water courses overflow their channels and run out over deeper slabs or ice lenses. The greatest chance of these types of avalanches will be later in the day after the rain has penetrated more deeply through the snow and melt runoff increases beyond it’s already high levels. Most other forecast areas will share this problem so if skiing in the rain is your thing, consider lift service today.

WEATHER: Rain should begin this morning and pickup in intensity into the afternoon. An inch of rain will fall before changing over to snow late tonight and in the wee hours of Wednesday. Temperatures, now standing at 42F will start to decline in the late afternoon and evening to around freezing at sundown and then down to around 10F by morning. 1-3″ snow may fall by morning. SW Wind will ramp up a bit from it’s current 45 mph or so as rain increases in intensity before slowing a bit later in the day. Overnight wind will shift to the NW and crank up to the 80-100 mph range by morning. Expect temperatures well below normal tomorrow.

SNOWPACK: Todays rain will be falling on an already rotten, unsupportive snowpack. Even packed trails will have the potential for postholing as water channels beneath the melting bonds between snow grains. All the warm weather has weakened the snowpack and encouraged the inevitable downhill creep of the snowpack. Smaller crevasses near rocks were opening over the past several days but were minor compared to what you could expect to see today. The main waterfall hole that opened yesterday in the Lip/Center Bowl area makes a crossing of the Tuckerman Ravine trail a dangerous proposition.

OTHER HAZARDS: Rain and more warm temperatures today continue to flood streams and undermine snow. Larger stream channels like the brook coming out of Tucks can be dangerous. Imagine falling into a treewell with water rushing through the bottom…..just as hard to get out of and with hypothermia and drowning a real possibility. To spice things up further, icefall potential will be on the rise today making Lunch Rocks an especially bad choice of places to hang out and enjoy the cold, wind driven rain.

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.
  • Posted 7:00 a.m. 4-15-2014. A new advisory will be issued tomorrow.

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

2014-04-15 Print friendly