Avalanche Advisory for Monday, February 29, 2016

All forecast areas of Tuckerman and Huntington Ravines have Moderate avalanche danger. Natural avalanches are unlikely but human-triggered avalanches are possible. Evaluate snow and terrain carefully.

AVALANCHE PROBLEM:  We are starting this morning with Low avalanche danger in both ravines.  The Moderate rating will develop as the forecasted weather moves in.  Strong west winds and 1-3″ of new snow, possibly mixed with rain or even all rain, will create the instability for the day.  New wind slab will form if this precipitation falls as snow due to forecast wind speeds and direction. If a mix of precipitation types fall, anticipate potential wet loose avalanches or even a wet slab. Travel in avalanche terrain today will require a vigilant eye on the weather to keep track of increasing danger and what type of danger that will be.

 WEATHER: Summit and valley temperatures hovered just below freezing overnight. Currently, a mid-elevation warm band sandwiched between the summits and settled cold air in the valleys, is yielding temperatures in the high 30’s in the Ravines, with 41F at Hermit Lake. The mercury will creep up even further this morning before the first of two cold fronts passing through the area today returns the temperature to more seasonable levels. The first front should arrive mid-day, bringing with it higher windspeeds (60-80mph) and a chance for 1-3” of new snow. Unfortunately, temperatures are such that Ravines may see rain rather than the desperately needed snow. A second front will arrive near or after dark. By midnight, winds will push even higher into the 90’s mph with gusts to 110mph overnight with temperatures falling to 0F by tomorrow morning. Our rating today is most influenced by the first fast moving system to arrive mid-day.

 SNOWPACK: Last night, it is likely that the warm air band encouraged slow settlement of the old, firm wind slabs that exist in a few strong lee areas like Sluice and the Lip. Given the lack of ice crust on the snow’s surface at Hermit Lake, it is possible that some softening of the icy melt/freeze crust has occurred in the Ravines but this softening will be short lived. Hard surface conditions will return as temperatures drop this afternoon and leave the potential for long sliding falls near the top of the list of hazards you’ll face. If the coming precipitation falls as rain expect our avalanche hazard to increase slightly due to increased load on the older wind slabs. If precipitation falls as snow, expect new wind slabs to develop and be the main stability concern. In either case, assessments will be challenging due to reduced visibility.

Icy conditions on trails are creating very slippery conditions. Microspikes for down low with crampons and an ice axe in the steeps areas are recommended. Ski conditions are generally poor on the Sherburne with long stretches of water ice, particularly lower on the mountain.

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 8:15am, February 29, 2016. A new advisory will be issued tomorrow.

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

2016-02-29

 

Sherburne Conditions February 28, 2016

The top of the Sherburne is a little better than what you’ll see in this video, but not by much. The upper trail is very hard icy snow and less water ice.

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Avalanche Advisory for Sunday, February 28, 2016

This advisory expires tonight at 12:00 midnight.

Tuckerman Ravine has Moderate and Low avalanche danger. The Sluice and Lip have Moderate avalanche danger. Natural avalanches are unlikely and human-triggered avalanches are possible. All other forecast areas have Low avalanche danger. Natural and human-triggered avalanches are unlikely. However, watch for unstable snow in isolated terrain features. The Lobster Claw, Lower Snowfields, and Little Headwall are not posted due to a lack of snow.

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

AVALANCHE PROBLEM: Areas of wind slab will be the primary avalanche problem today. In the Sluice and Lip, these areas are sufficiently large to warrant a Moderate rating. If you are looking to trigger an avalanche today, your most likely location would be in the Lip. Other areas rated Low may also have smaller areas of wind slab in sheltered areas that are worth avoiding. Examples include Right Gully, Chute, and Central Gully, but be watchful for unstable slabs wherever you travel.

Aside from avalanches, falls in steep terrain are a very serious threat. Vast amount of icy surfaces exist; it will be very challenging to arrest a fall on this surface. Fall lines are chock full of rocks and trees, increasing the risks associated with a fall. Consider using roped travel techniques for climbing through steep icy terrain, especially for those without significant and relevant mountaineering experience.

WEATHER: Thursday and into Friday the mountain received about 3” (7.5cm) or more of new snow. No additional precipitation has fallen since then, and it’s unlikely that we’ll get any more today. Light amounts of snow may fall tonight and Monday, before another potentially wet storm on Tuesday/Wednesday. Today your biggest weather issues will be thick fog and strong winds above treeline.

SNOWPACK: The rain that fell last week did a great job resetting the layers in the snowpack. For today’s avalanche issues, we aren’t much concerned about what is below the most recent crust. It’s the little bit of snow blown into wind slabs above the crust that’s the cause of our avalanche concerns. Due to the crowds on the mountain this weekend, we haven’t been able to get our hands into this snow to gauge its stability directly. Skiers intent on making turns in softer snow should be aware that the only places we have concerns about the stability appear to be the most appealing skiing. Be cautious out there.

The amount of ice that is present on Mt. Washington is incredible. This is not only the steep icy surfaces already mentioned in the ravines. It’s also on the lower Tuckerman Ravine Trail, the Alpine Garden Trail, the John Sherburne Ski Trail…we are strongly recommending bringing some form of traction for lower elevation trails and crampons and ice axes for anything steep or in the alpine. Skiers, you’ll want to carry your skis to the top of the switchbacks before trying to skin up the rest of the way.

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 8:00am, February 28, 2016. 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

2016-02-28

Avalanche Advisory for Saturday, February 27, 2016

This advisory expires tonight at 12:00 midnight.

Tuckerman Ravine has MODERATE and LOW avalanche danger. Right Gully, Sluice and the Lip have Moderate avalanche danger.  Natural avalanches are unlikely and human triggered avalanches are possible.  Heightened avalanche conditions exist on specific terrain features. Evaluate snow and terrain carefully to identify features of concern.  Other forecast areas have Low avalanche danger. Natural and human triggered avalanches are unlikely except in isolated pockets. The Lobster Claw, Lower Snowfields, and Little Headwall are not posted due to an overall lack of snow in these areas.

Huntington Ravine has LOW avalanche danger. Natural and human triggered avalanches are unlikely except in isolated pockets.

AVALANCHE PROBLEMWind Slab is the avalanche problem today.  High winds blew the 3″ of new snow that fell on Thursday night and Friday morning off the alpine snowfields and down into some areas of the Ravines.  Most areas are scoured to old icy surfaces, but expect a few places to harbor some instabilities.  These locations are limited, but stay aware of changes as you transition from old ice to new slab.  A busy Saturday should also focus your attention to others above and below you.

WEATHER: High winds have dropped off for a beautiful start to the day.  Cool temperatures will rise to about 10F on the summit with an increasing W wind moving from 30 to 40 mph, gusting over 80 later today.  Expect a growing cloud deck with a slight chance of afternoon snow showers.  This shouldn’t effect danger ratings, but will reduce this morning’s awesome visibility.

SNOWPACK: With March just around the corner I am finally facing the music that winter has little chance of recovery.  All areas continue to be thinly covered and am starting to believe some of our forecast areas will never get a rating this season.  Our travel up the mountain has fallen apart and we are now walking the lower sections, which has us scrambling to get the advisory out on time.  The main snowpack issue are new slabs at the surface in some areas.  Theses issues were developed yesterday through the day as winds increased and are sitting on a slick old surface due to rain from several days ago.  Anticipate poor bonding and be suspect of slab strength until proven otherwise.  New slabs are most prominent in Tuckerman’s Lip and Sluice, followed by Right gully.  The Center Bowl, the upper climber’s right of the Chute, and down low in Left gully have some isolated pockets, but are most accurately rated at Low.  In Huntington, the standout pocket is in the lower section of Central Gully.  Otherwise the vast majority of Huntington is scoured down to old surface.  Falls are the main hazard today.  It will be very challenging to stop any kind of fall on the old icy surface.  A rope would be a prudent choice for groups having members of limited skills and experience in terrain when the consequences are high.

The Sherburne ski trail ice is growing by the day and is the most I have seen in 26 years.  Don’t take this as a challenge, but you will not be able to get up the Tuckerman Ravine trail from Pinkham without some kind of traction like crampons of micropikes.  We hope a busy day will grind up the ice a bit.

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 8:40am, February 27, 2016. A new advisory will be issued tomorrow.

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

2016-02-27

Avalanche Advisory for Friday, February 26, 2016

This advisory expires tonight at 12:00 midnight.

All forecast areas of Tuckerman and Huntington Ravine have LOW avalanche danger. Natural and human triggered avalanches are unlikely except in isolated pockets. The Lobster Claw, Lower Snowfields, and Little Headwall are not posted due to an overall lack of snow in these areas.

 AVALANCHE PROBLEM: Pockets of Wind Slab are the avalanche problem today.  The rain and melt water in the snowpack from the recent weather maker is now freezing quickly as temperatures continue to plummet over the past 18 hours.  This newly frozen surface will act as the bed surface for the light snow which added up to between 2.5″ (6cm) and 3″(7.5cm) on the Washington summit last night.  Expect pockets of new wind slab in strong lee areas such as below steep roll overs, steep water ice, rock buttresses, etc.

WEATHER: Since yesterday afternoon, the summit mercury has fallen from +34F to -4F and continues to drop. Upslope snow showers, from yesterday afternoon until now, have added up to about 3″ (7.5cm) but should start tapering off this morning.  Expect below 0F temperatures and west winds in the 60-70 mph range with low visibility this morning creating challenging travel conditions above treeline. Winds should shift from the NW later with an increasing wind speed, peaking above 90mph (144kph).

SNOWPACK: Unfortunately, the Ravines are shrouded in frozen fog this morning and obscuring the view of signs of recent avalanche activity. The heavy rain and warm temperatures fell on a mix of old melt freeze crust as well as more recent, predominantly pencil hard, wind slabs. Wet avalanches are notoriously difficult to predict but we are expecting to see signs of it in many areas, hopefully later today if the summits clear. The rain wreaked havoc on the already boney east side trails, as you might expect. Water ice floes stretch wall to wall on the Tuckerman Ravine trail as well as the Sherburne ski trail. Though the stretches of blue water ice slowly decrease in size and extent with altitude, there is still boilerplate, refrozen snow in most places. There is a dusting of the new snow and drifts due to the high winds this morning. I would not even think of leaving Pinkham parking lot without microspikes on much less leaving sharp, steel crampons in the car. The Lion Head Winter Route is likely to be a mix of refrozen crust (neve) along with ice and bare rock making for higher consequences and more challenging climbing than in heavier snow years.

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 8:20am, February 26, 2016. A new advisory will be issued tomorrow.

Chris Joosen/Frank Carus, Snow Rangers
USDA Forest Service
White Mountain National Forest
(603) 466-2713 TTY (603) 466-2856

2016-02-26

Avalanche Advisory for Thursday, February 25, 2016

This advisory expires tonight at 12:00 midnight.

All forecast areas of Tuckerman and Huntington Ravine have Considerable avalanche danger. Dangerous avalanche conditions exist. Natural avalanches are possible and human-triggered avalanches are likely. The Lobster Claw, Lower Snowfields, and Little Headwall are not posted due to an overall lack of snow in these areas.

 AVALANCHE PROBLEM: Two inches (5cm) of rain over the past 36 hours, with 3/4″ (1.9cm) or more of that falling overnight, has stressed our snowpack. Deeper layers could fail and slide in a Wet Slab avalanche as this water continues to drain through upper layers and reach weak layers below. Ice dams in the more sizable drainage channels such as the Lip waterfall in the Headwall of Tuckerman Ravine have a history of stopping up and blowing out in sizable wet avalanches. If today’s weather forecast isn’t enough to keep you away from slopes and gullies in the Ravines then the threat of a natural wet avalanche should have you choosing your route through the rotten snowpack very cautiously.

WEATHER: The bulk of the rain has passed but expect fog, rain showers and even the threat of a passing thunderstorm to continue through the afternoon. 2″ (5cm) of rain was collected at Hermit Lake in the past 24 hours. Currently summit temperature is 37F. Temperatures will begin to drop later today as a cold front passes through the area with an increase in wind speeds this afternoon. Air temperatures are not expected to reach the freezing point on the summit until sundown which will begin to refreeze our snowpack and reduce the threat of wet avalanche activity through the night. Snow showers should develop overnight with 1-3″ new snow possible.

SNOWPACK:  By tomorrow we will have officially gone through another “hitting of the reset button”.   Before yesterday’s warm up there was a high degree of snowpack spatial variability with a variety of weaknesses in different areas.  This left us a little spooked in isolated pockets and very confident on old icy surfaces.  Beginning yesterday morning light rain began across the mountain with intensity picking up late in the day.  Following a brief period of wet snow early, avalanche terrain got hit with about 1.75” (4.5cm) of rain as of 6am this morning.  Avalanche danger increased quickly through the afternoon yesterday, peaking during the overnight.  Early this morning we have come off a period of High avalanche danger and currently sit at Considerable due to concern of wet slab failure.  Through daylight hours today, we expect a slow decrease in the avalanche danger as rain and melt water continue to drain from our thin snowpack.   We are likely to pick up a bit more rain this afternoon followed by a changeover to snow.  Rain adds weight, lubricates ice lenses that restrict percolation, and melts bonds between snowpack grains reducing strength. These big three results of rain on an initially cold snowpack screams “watch out” for us.  This requires either very conservative well-thought through risk decisions using vast experience, or avoidance.  Eventually, on Friday morning the snowpack lock up will bridge over deeper concerns and the new issues may be related to new upslope snow.  This new snow is expected as temperatures drop bring us back to a potential wind slab problem tomorrow.

The John Sherburne Ski Trail today is wet with running water, is large sections of ice, however it is vastly better that the grim survival skiing you will likely encounter 24 hours from now.

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 8:15am, February 25, 2016. A new advisory will be issued tomorrow.

Frank Carus/Chris Joosen, Snow Rangers
USDA Forest Service
White Mountain National Forest
(603) 466-2713 TTY (603) 466-2856

 

Avalanche Advisory for Wednesday, February 24, 2016

This advisory expires tonight at 12:00 midnight.

All forecast areas of Tuckerman Ravine will have Considerable avalanche danger. Dangerous avalanche conditions will exist. Natural avalanches will be possible and human-triggered avalanches will be likely. The Lobster Claw, Lower Snowfields, and Little Headwall remain not posted due to an overall lack of snow in these areas.

Huntington Ravine has Considerable and Moderate avalanche danger. Yale, Central, Pinnacle, Odell, South, and the Escape Hatch have Considerable danger. Natural avalanches are possible and human-triggered avalanches are likely. North and Damnation gullies have Moderate avalanche danger. Natural avalanches are unlikely and human triggered avalanches are possible.

 AVALANCHE PROBLEM: Avalanche danger will be increasing quickly today as new precipitation changes from snow to a wintry mix and then to rain. All areas will be increasing in danger, but the type of problem you’ll find depends on your aspect and timing. Early on, the dominant problem will be wind slab, either previously existing or newly developing slab from today’s snowfall. Later, as temperatures rise, you will be faced with a wet slab or wet loose avalanche problem. New wind slabs will build primarily on N-facing slopes, and to a lesser degree on E-facing slopes. Prior to new snow, problems existed largely on E-facing slopes such as Chute and Lip in Tuckerman or Central and Pinnacle in Huntington.

WEATHER: It’s these types of storms that make New Englanders a hardy bunch. A few inches of snow followed by record breaking warm temperatures and heavy rain, only to be followed by a sharp drop in temperatures before the weekend. Today we can expect up to a few inches of snow to fall before we start to see a wintry mix of precipitation types. This will come in on a S wind in the 35-45mph (56-72kph) range. As the changeover takes place, the wind speeds will start to increase significantly with hurricane force gusts in the afternoon. Temperatures will rise today, easily surpassing the freezing mark at all elevations, likely breaking records in the nighttime. Total liquid equivalents for this storm will be somewhere between 1″ and 3″, most of which will come as rain overnight and on Thursday.

SNOWPACK: The key to today’s advisory is to understand that we will have increasing avalanche danger on a variety of aspects due to new snow and rain. If you need (or want) deeper information than that, I hope it’s only for your personal interest, and not to help you make travel decisions. But here it is anyhow…We had a widely variable range of stability out there prior to new snow this morning. Good to fair stability could be found in much of the terrain, but our observations kept bringing us back to a Moderate rating due to there being too many different layers in a highly variable snowpack. Much of the slabs we found were 1F hard with weak interfaces within the slab at various depths above the weakening crust. I could see avalanche activity in today’s wind slab stepping down into these layers, or as rain saturates the snowpack, the failure initially being at or below the crust layer. All told, it’s a fairly complex snowpack for now, so focus your attention on the weather today and you’ll be see the most important data.

The Lion Head Winter Route is open and the recommended east-side route to the summit that avoids avalanche terrain. The John Sherburne Ski Trail is icy and challenging beneath a veneer of new snow.

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 8:15am, February 24, 2016. 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

Huntington Photos, February 23, 2016

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Damnation desperately wanting more snow

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Escape Hatch

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Yale Gully

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Huntington south side

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Tucks had an ominous gray cloud while the snow was lit by morning sunshine.

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Hillman’s area

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North Gully

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Helon contemplating his next move on the second pitch of Pinnacle.

Avalanche Advisory for Tuesday, February 23, 2016

This advisory expires tonight at 12:00 midnight.

All forecast areas of Tuckerman Ravine have MODERATE avalanche danger. Natural avalanches are unlikely and human-triggered avalanches are possible. Heightened avalanche conditions exist. Evaluate snow and terrain carefully and identify features of concern. Lobster Claw, Lower Snowfields, and the Little Headwall are not posted due to lack of snow cover. Exercise caution in these areas.

Huntington Ravine has MODERATE and LOW avalanche danger. Yale, Central, Pinnacle, Odell, South, and Escape Hatch have Moderate avalanche danger. Natural avalanches are unlikely and human-triggered avalanches are possible. Evaluate snow and terrain carefully and identify features of concern in these areas. North and Damnation have Low avalanche danger. Natural and human-triggered avalanches are unlikely. Watch for unstable snow on isolated terrain features and well-sheltered lee areas.

 AVALANCHE PROBLEM: Wind slab is the primary avalanche problem today. These slabs are varying in size, thickness and location.  Many areas with a Moderate rating can be navigated with wise travel assessments.  Areas rated Low will contain pockets of isolated wind slabs that could be reactive to a human trigger.  All areas will contain some areas of exposed melt-freeze crust.  Wise travel choices will be crucial today.  Runouts to all gullies are slow to fill in and a fall on impenetrable melt-freeze crust or due to being swept by a small isolated pocket of wind slab could have disastrous results.

WEATHER:  The 9″ of snow that arrived over the past weekend arrived on SW and W winds that deposited much of this snow into our ravines.  Temperatures have remained cold, preventing the stabilization of this wind slab.  Yesterday’s sun, while bright and direct, had no warming effect on the snowpack.  Today’s temperatures will be warmer than the past several, however I expect the developing clouds due to the incoming low pressure to prevent further warming. Precipitation will start well after dark and with the significant increase in temperatures expected(in the 40s), tomorrow we’ll be saying, “You should have been here yesterday!”

SNOWPACK: Today, the bottom of my snow pit would be the melt-freeze crust that formed on February 17.  I found it 20cm thick in several places, hard enough that I had to backtrack to put my crampons on, and impossible to put a shovel through.  The wind slab sitting on top of this is incredibly variable, which will make wise travel decisions crucial today.  The wind slab formed on SW winds and since has been subjected to strong W winds for several days.  Lee areas like the climber’s left of Right Gully and approaching the Chute, the top of Hillman’s, Central in Huntington, and the area below the ice in Pinnacle all have smooth surfaces of new snow, clearly indicating this wind slab.  Tests in Right and Left Gully found this slab to fail on CT11-16 on the melt-freeze crust with a shear of Q3.  We also found several layers in the wind slab itself to fail in the CT5-10 range with clean shears.  Our extended column did not propagate.

Throughout both ravines, there is large amounts of debris from the wet avalanche cycle last week.  This can be seen in the runouts of Yale, Central and Pinnacle in Huntington as well as the Center Bowl and Chute in Tuckerman.  Upon approaching the choke of the Chute, we found an 8″ thick flank of a wind slab that avalanched most likely Saturday night.  This was indiscernible from below as it had reloaded with graupel and other heavily rimed particles that fell early Sunday morning.  Evidence of this avalanche cycle was also visible in Right Gully, with a crown 10″ thick tapering to old surface in 10 feet.  The remaining pocket is less than 50 square feet.  I would expect these touchy pockets to linger in multiple areas around the ravines.  Areas of heightened concern today in Huntington would be the start zones of Damnation and Yale, Central Gully, and the snowfields below the ice bulges of Pinnacle and South.  In Tuckerman, I would exercise extra caution in Right, Sluice, the Lip and the Chute.  Other areas harbor smaller pockets of wind slab and larger areas of knife-hard melt-freeze crust that will require crampons even on low-angled slopes.  Spatial variability is the name of the game today.

The Lion Head Winter Route is open and the recommended east-side route to the summit that avoids avalanche terrain. For one of the few times this winter, the John Sherburne Ski Trail looks like good skiing.

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 9:00am, February 23, 2016. 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

02-23-2016

 

Avalanche Advisory for Monday, February 22, 2016

Tuckerman and Huntington Ravine have MODERATE avalanche danger. Natural avalanches are unlikely but human-triggered avalanches are possible. Evaluate snow and terrain carefully.

 AVALANCHE PROBLEM: Wind slab is the primary avalanche problem today. Widespread, smooth slabs reach from wall to wall in most gullies in both Ravines this morning. These slabs have a layer of lower density snow beneath them and will create challenging conditions in which to apply safe travel skills, careful terrain management as well as ongoing, critical assessment of slope stability. Expect the wind slabs to vary in thickness with the consequences of triggering any size avalanche particularly dangerous due to the ice crust beneath and the many rocks and ice cliffs that remain exposed.

WEATHER:  We received around 9” (22cm) of new snow in the past 3 days with only 1” (2.5cm) falling yesterday. Wind speeds ramp up for a brief period but no real scouring occurred. Today’s weather should be clear and cold with summit temperatures around 0F. Currently, brilliant sunshine and calm winds at Ravine level are providing a nice break from the last several days of murky gray but unseasonably warm weather. This time of year the increased daylight and angle of the sun has the possibility of rapid warming on the list of concerns but we won’t likely get there today. Expect continued cold today as high pressure settles in with NW winds in the 30-45mph range.

SNOWPACK: Only a few areas of the Feb 17th melt freeze crust are showing in the Ravines. The avalanche debris showing in Huntington Ravine is from wet loose activity last Thursday. Higher in the start zones a crown line in Chute from the same cycle is now buried as is the older crown line through Center Bowl and the Lip. The 8” (20cm) of new snow coupled with southwest winds on Friday and Saturday really filled in upper sections of Hillman’s Highway and Left Gully, though both are still well behind a normal snow level. Winds shifted from the south to the west, crossloading or just plain loading much of the terrain, leaving very little of the textured sastrugi snow that we see following high winds. South facing gullies in Huntington indicate that some scouring may have occurred early in the 8” storm cycle but subsequent cross loading has built slabs in the mid-sections.

The Lion Head Winter Route is open and the recommended east-side route to the summit that avoids avalanche terrain. The John Sherburne Ski Trail is in a typical mid-winter state with packed snow and some bare patches of ice that become a more significant problem the lower you go on the mountain. Recent snow was highly elevation dependent with some rain falling at Pinkham Notch so expect icier trail conditions down low.

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 8:20a.m., February 22, 2016. 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

2016-02-22 Printer friendly version