Avalanche Advisory for Wednesday February 20th, 2013

This advisory expires at midnight 2-20-2013

Tuckerman Ravine has HIGH, CONSIDERABLE, and MODERATE avalanche danger.  The Sluice, Lip, Center Bowl, and Chute have High avalanche danger.  Natural avalanches are likely and human triggered avalanches are very likely.  Very dangerous avalanche conditions exist. Travel in avalanche terrain is not recommended.  The Lobsterclaw, Right Gully, Left Gully and Hillman’s Highway have Considerable avalanche danger.  Natural avalanches are possible and human triggered avalanches are likely.  Dangerous avalanche conditions exist and conservative decision making is essential. The Lower Snowfields and the Little Headwall have Moderate avalanche danger. Natural avalanches are unlikely and human triggered avalanches are possible.

Huntington Ravine has CONSIDERABLE avalanche danger.  Natural avalanches are possible and human triggered avalanches are likely.  Dangerous avalanche conditions exist and conservative decision making is essential.

The summit has received approximately 4″ (12.5) of new snow, as have we down at Hermit Lake, with an additional 1-3″ expected through today.  Snow began last night around 5pm with winds from the S until about midnight when the shift began towards our current NW.  Southern winds associated with snowfall began with a velocity close to 40mph and fell through the evening into the teens. As winds transitioned to the NW through the early morning velocities increased again and have been gusting into the 60’s mph since dawn.  They are forecasted to continue rising, gusting over 70 later today.

As wind speeds slowed to 15mph around midnight, with new snow falling, a lighter “fist” hardness layer was deposited. In quick hand shears in my travels today I am getting easy shears on this unconsolidated soft layer.  This mid slab layer is the main weakness I am seeing this morning and the most likely issue leading to slab fracture and failure in the Ravines.

With cold air in place we are finding snow in the 5% range deposited in the trees down low.  However, in locations affected by the wind delicate stellars crystals are being destroyed into fragments, increasing the densities as shown at our snowplots and at the summit.  Therefore as winds continue to ramp up I expect slabs of increased hardness to be deposited over the early morning loose layer.  With this said this “increased” hardness is still likely pretty soft in sheltered locations, perhaps ”4 finger”, so anticipate new slabs to be delicate and reactive to human triggers.  As upslope snow continues today the increasing avalanche danger trend will continue.  Expect to see the potential of natural avalanches to be highest on the largest E and SE faces, with Tuckerman’s Lip and Center Bowl leading the charge.  It is likely that the forecasted snow tonight and tomorrow will continue our heightened avalanche dangers for Thursday.

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 8:30. 2-20-2013. A new advisory will be issued tomorrow.

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

2013-02-20 Print Version

 

Avalanche Advisory for Tuesday, February 19, 2013

This advisory expires at 12:00 midnight, February 19, 2013

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

All forecast areas of Huntington Ravine have Low avalanche danger.  Natural and human triggered avalanche are unlikely.

The damage done to our snowpack by yesterday’s high winds (129 mph or 210 kph peak wind speed) is the overwhelming impression of Tuckerman from Hermit Lake. Field time yesterday afternoon revealed evidence of four avalanches though the evidence of more would have been erased by the high winds.  Firm, stable, wind sculpted snow is the predominate surface in most of Huntington and Tuckerman Ravines today. Larger areas of windslab exist in the gullies rated Moderate with smaller pockets in Low rated gullies. The windslab creating our concern today will appear smoother and will be less resistant to triggers than the more textured and sculpted areas.  Beware of cracking and hollow sounding slabs in select lee areas. Though further field time today will help us more accurately pin down the hazard in our Moderate rated gullies within that rating, some clues visible from Hermit Lake point to the fact that further loading occurred as the winds died down overnight.  The three foot crown line below the ice in the Lip area has reloaded so that only about a foot, or maybe a bit more, is now visible. Right Gully was loaded more than scoured during the event but with little snow prior to the wind, only enough new slab exists to create a Moderate hazard.  Center Bowl and the Chute were heavily wind packed but some hangfire still exists in the upper portion of the hourglass below the ice in Chute.  The climbers upper left exit of Left Gully slid and didn’t reload but the upper right pocket would be best avoided or approached carefully. Hillman’s Highway was scoured out or wind hammered.  Huntington Ravine gullies suffered significant scouring.  The northern gullies look like they did a month ago…rocks near the top and a thin ribbon of ice and snow below. Central, Pinnacle and Odell Gully were also mostly scoured.

Today’s weather forecast is creating a good window for those looking to get out and climb and hike during this busy vacation week. Forecasting for crowds has proven to be challenging but it is safe to say that more than the usual caution is warranted due to the increased likelihood of people generating rock and ice fall or even finding the sweet spot that triggers the slab above you. Afternoon fog and cloud cover is forecasted to descend through the afternoon as winds increase so consider your pace and account for deteriorating visibility. Temperatures will rise to the mid 20’s on the summit but we have already hit 32F (0C) at Hermit Lake at 7:30 am with calm winds. Enjoy the balmy conditions while they last.  Enough snow is forecasted tonight and tomorrow to change our avalanche animal dramatically so check in tomorrow morning for the latest forecast before committing to a route.

Remember that Lions Head trail is a steep mountaineering route with several areas of 3rd class rated terrain.  Climbing rock and steep snow and ice slopes in crampons may require ropes to protect you or members of your party.  Anticipate possible delays due to crowds and be patient with others as they negotiate this terrain which has been the scene of numerous injuries in the past.

 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 8:15a.m., February 19, 2013. A new advisory will be issued tomorrow.

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

2013-02-19 Print friendly

Avalanche Advisory Monday 2-18-2013

This advisory expires at 12:00 midnight, February 18, 2013

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

All forecast areas of Huntington Ravine have Low avalanche danger. Natural and human triggered avalanches are unlikely except on isolated terrain features.

Hopefully if you’re reading this advisory today, it’s from the warmth and comfort of an indoor facility. Current conditions on the mountain are exceptionally brutal. Due to clouds and blowing snow, visibility is near zero.  Temperatures are just above zero F at Hermit Lake. Some trees are swaying back and forth like hippies at a Grateful Dead show, while other trees look more like headbangers at a Metallica concert. Don’t be fooled by the diminishing winds and clearing skies forecasted for today; the wind will only decrease 80-100mph (130-160kph) and you should expect airborne snow to be acting as a sandblaster until well after dark today.

Yesterday, the summit recorded 3.6″ (9cm) of snow with increasing wind speeds reaching a crescendo this morning. They’re currently 115mph (185kph) with gusts pushing close to 130mph (210kph). What is this doing for snow stability? The easier ravine to forecast is Huntington. Sustained winds overnight have likely scoured out and wind-hammered the gullies into stable hard slab and old exposed crust. There may be small and isolated pockets of unstable snow in the most well-protected locations, so as always, be vigilant to changing conditions. We have yet to get a view of the ravines, so there is some uncertainty to the rating, but I am fairly confident that it would be difficult to find stability problems in Huntington.

Tuckerman is a little different story. It’s less prone to scouring than Huntington due to its being more protected from strong winds. There is currently wind transport of snow taking place in all locations of Tuckerman. The snow moving around is likely from yesterday morning’s snowfall as well as older snow being picked up from the other side of the mountain. The Considerable forecast for many areas is due to the potential for slabs building in lee areas, creating the possibility of naturally triggered avalanches in these areas. Any slab being formed today will be hard and dense, which are typically quite strong. However, if these hard slabs do fracture and fail, the destruction left in their wake can be impressive. Overall I suspect that many of the areas are being hammered by the wind so strongly that they will be strong enough to not avalanche, but until we can confirm this, the safe bet is to go with the reliable data rather than the assumption. In this case, I know for certain that snow will continue to be transported into Tuckerman at a good rate today. The areas posted at Considerable are the strongest contenders for unstable snow. In areas posted at Moderate, remember that “unlikely,” which is used in the definition for naturally triggered avalanches in Moderate hazard, is different from “not possible,” which is not part of any danger rating definition but is commonly how we see people act in avalanche terrain. The lesser rating reflects the overall hazard compared with other forecast areas, but Moderate avalanche hazard is still dangerous, particularly when active loading is taking place.

Winds have created some good drifts on the Tuckerman Trail. My hope is that they also filled in the Little Headwall. We may find out more later today. The Sherburne will have some icy scoured locations and a few deep drifts to play around on.

 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 8:35a.m., February 18, 2013. A new advisory will be issued tomorrow.

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

2013-02-18 Print Friendly

Avalanche Advisory for Sunday, February 17, 2013

This advisory expires at 12:00 midnight, February 17, 2013

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

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

Avalanche danger in all forecast areas will be increasing from yesterday’s ratings through today!

Today’s impending wind event was apparent this morning as I got in the car in Brownfield, Maine. A steady wind and distant dull roar brought memories of near misses by hurricanes as a young lad growing up in the South. The big low pressure system, now southeast of Cape Cod, will remain too far away in the Gulf of Maine to bring the snow that the area desperately needs. However, pressure differentials will be deep enough to generate significant winds with 1-3” (3-8cm)of new snow today and a trace to 2” (5cm)tonight. The new snow, which is in the 4-5% range so far, will be transported by wind which will increase through the day. Currently, winds are blowing from the N at 35-50 mph (55-85 kph) but will shift to the NW and increase in velocity through the day to the 100 mph (160 kph) range this afternoon. This will load the upper avalanche start zones near the top of Damnation, Yale, Central and crossload other areas in the same gullies as well as Pinnacle, Odell, and South. North and Escape will also receive crossloaded pockets of snow but natural avalanches are unlikely there due to the scarcity of continuous snowfields and abundance of anchors. Lookout for the light density snow piling up into sizable slabs at the base of steep ice and rock features. In Tuckerman Ravine, the wind and new snow will also conspire to build new slabs in Right Gully, Sluice, Lip and crossload other areas particularly across the bowl in the Center Headwall Left Gully and even Hillmans Highway. Lobster Claw and Hillmans are rated at Moderate due to the smaller size of snowfields there but careful travel there is still warranted. The lower half of Hillmans is mostly ice chunder with a veneer of snow due to the huge ice dam slush burst during our last thaw.

If the forecasted snow totals pan out, the possibility of natural avalanches is definitely there in both ravines. If snowfall is lighter than expected, we still have two issues to consider. One is the cold slabs remaining from Monday and Tuesday.  These slabs are fairly stubborn, both in their longevity and their resistance to triggers. Hard wind slabs are tempting due to easier travel and consistently carvable skiing but the softer layer which exists below can spell doom when some unlucky soul finds the sweet spot that fractures and fails the slab.  Several skiers, including Joe and I, found thick slabs over one hardness step lighter snow in Central, Left and South over the course of the last two days. These slabs would take a large trigger, a new heavy load or a particularly well aimed trigger in a thin spot between rocks, for instance.  A natural avalanche of today’s storm snow could also step down into this layer creating a larger than expected problem.

Difficult off trail travel will make bailing off of usually packed out trails on the ridgetops a significant challenge.  The high windspeeds and low visibility will add to the challenge today. Speedy ascents will be the best option today to get off the mountain before the white witch unleashes her dragon. Remember that 60-75 mph (95-120 kph) NW summit winds make walking increasingly difficult and accidents more and more likely. Windspeeds will increase beyond that to upwards of 120mph (190 kph)tonight so wise climbers will adjust turn around times accordingly. Coupled with a plunging mercury to -15F (-26C) will make for unforgiving brutal conditions.

 

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 8:45a.m., February 17, 2013. A new advisory will be issued tomorrow.

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

2013-02-17 Print friendly

Avalanche Advisory for Saturday 2-16-2013

This advisory expires at 12:00 midnight, February 16, 2013

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

Huntington Ravine has MODERATE and LOW avalanche danger. Central and Odell gullies have Moderate avalanche danger.  Natural avalanches are unlikely and human triggered avalanches are possible. All other forecast areas in Huntington have Low avalanche danger. Natural and human triggered avalanches are unlikely.

Whether you’re here for just today or for the long holiday weekend, today looks to be the best day to get out and play on Mt. Washington. Temperatures will be seasonable, winds will be on the light side, and there is a chance that clouds on and above the summit will be breaking up. We got a dusting of new snow early this morning, but it’s not enough to increase the avalanche hazard. The stability problems we are currently monitoring are left over from two days of light snowfall on Monday and Tuesday totaling about 5″, which fell with strong SW winds Monday then strong NW winds on Tuesday. Through the course of the past week, we’ve been able to lower the danger ratings in a number of locations. Today, Pinnacle is the only additional area moving from Moderate to Low. The other areas that remain posted at Moderate will continue to trend in a similar direction, but we don’t have the confidence needed to drop them a full rating.

What you’ll find in many areas, particularly those posted at Moderate, is fairly deep wind transported snow. Layers of softer, weaker snow, and pools of graupel in some places, are lying underneath slabs that are more firm than what is below. We’ve seen clean shears at a lot of the interfaces between the various layers, but overall the snowpack is lacking “snap.” The technical way to say this is that there is limited potential for fracture propagation, but I like to think of it in terms of made-up words like snappiness. While the overall snowpack has limited snapiness, in some locations this property exists sufficiently for a person to trigger an avalanche. Examples include weak points in snow near buried rocks or ice bulges, shallower snow on top of water ice or rain crust, and more open steep slopes such as under the Lip in Tuckerman. Avalanche runout paths are not at all forgiving right now, most are filled with rocks, ice chunks, trees, etc., so the consequences of being involved in even a small slide could be dire.

It’s a holiday weekend, which typically means a lot of people on the mountain. While you and your group may be making good choices, don’t expect everyone out there to be knowledgeable about avalanches. Where you see tracks does not necessarily equate to prudent decisions! Pay attention to who may be above and below you, and whenever possible avoid traveling in the runouts of avalanche paths. The full fury of winter on Mt. Washington will be on display tomorrow and Monday. You’d be wise to get an early start Sunday and move quickly, because conditions will worsen through the day.

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 8:10a.m., February 16, 2013. 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

2013-02-16 Print Friendly

Avalanche Advisory for Friday, 2-15-2013

This advisory expires at 12:00 midnight, Friday 2-15-2013

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

Huntington Ravine has LOW and MODERATE avalanche danger. North, Damnation, Yale, South, and Escape Hatch have Low avalanche danger. Natural and human triggered avalanches are unlikely. Central, Pinnacle, and Odell have Moderate avalanche danger.  Natural avalanches are unlikely and human triggered avalanches are possible.

Though less than ideal weather conditions exist today for skiing, generally good stability could yield nice skiing and riding  in Tuckerman Ravine today for those willing to lower their standards a bit.  Our snowpack is still shallow for this time of year so lots of ice is showing in the headwall and Sluice and lots of bushes will limit you to short radius turns in Lobster Claw, Right and lower in Left Gully. Safe travel techniques when skiing will be challenging due to limited visibility, due to fog and a trace to 2″ (5cm) of new snow coming and may necessitate short pitches of skiing in order to maintain “eyes on” your partner. Climbers will find lots of ice trending to the “fatter” side in Huntington Ravine gullies.

Pockets of pooled, heavily rimed snow crystals are the areas of concern in both ravines today. Though not widespread, you will find areas of windslab on top of the weak rimed interface that are reactive to a moderate to hard trigger.  If you stumble into a larger, deeper area of this slab, you could trigger a consequential avalanche.  Yesterday, Chris and I observed several reactive layers, varying in depth from 6″-12″ (15-30cm), created by changes in snow density. These weak interfaces are probably deeper, perhaps significantly, in places.  Stay tuned in to the qualities of the upper layer(s) of snow and be alert to changing cohesion and reactivity of the slab.  Cracks shooting out more than a foot or so are a warning sign to remind you to manage the hazard by either tweaking your route to avoid the slab or finding and placing pro.

Boot penetration averages around 25 cm with deeper postholing in the faceted areas around rocks and bushes. Additionally, old rain crust is showing in spots and harder windboard exists in others. There was strong solar gain in the upper 4″ (10cm) of the snow on steep south facing terrain that moistened the snow and helped the stability process but created a bit of sun crust today.  Be sure to check our Weekend Update later today or this evening for more information about the busy upcoming holiday weekend.

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 8:35a.m. Friday 2-15-2013. 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

2013-02-15 Print friendly

Avalanche Advisory for Thursday, February 14, 2013

This advisory expires at Midnight, Thursday 2-14-2013

Tuckerman Ravine has LOW and MODERATE avalanche danger.  Hillman’s Highway, Lower Snowfields, the Little Headwall and Lobster Claw have Low avalanche danger. Natural and human triggered avalanches are unlikely. Right Gully, Sluice, Lip, Center Headwall, Chute and Left Gully have Moderate avalanche danger. Natural avalanches are unlikely and human triggered avalanches are possible.  Evaluate snow and terrain carefully to identify features of concern.

Huntington Ravine has LOW and MODERATE avalanche danger. Escape Hatch has Low avalanche danger. Natural and human triggered avalanches are unlikely.  All other forecasted gullies have Moderate avalanche danger.  Natural avalanches are unlikely and human triggered avalanches are possible.

Time and physical processes have brought slow stabilization to the windloaded areas of both ravines.  A wide variety of surface conditions exist so climbers and skiers planning  a trip into the ravines should be prepared for anything from hard wind slab, bullet hard rain crust as well as areas of soft snow thrown in to make things more interesting.  Most areas rated at Moderate are at the low end of the rating so arm yourself with key weather data and exercise sound travel skills today.

Over the past three of days the summit received 5.5” (13 cm) of new snow on winds coming from the SW to the NW with the majority of the snow (5.1″) falling on Monday and Tuesday. Winds abated through the day yesterday, with speeds dropping steadily from the 50’s mph 24 hours ago to around 25 mph by lunchtime yesterday and further into the teen’s mph (15-30 kph)where they have remained for the last 12 hours.  The low windspeeds have laid a veneer of new snow which is obscuring many of the visual clues that indicate the texture and, by extension, the travel qualities of the snow pack.  Opportunities to visually assess the snow will increase as the clouds lift through the day but expect a mix of riding and skiing qualities top to bottom in any gully from boot top height, but wind affected, snow to icy crust more suited to World Cup downhill record setting courses.  Be on the lookout for gray old surface just peeking through the new snow.  While the Chute, sections of the Center Headwall and the Lip appear attractive at first glance, remember that these areas suffered scouring as well as cross loading during the nor’Easter so the existing snow is extremely variable in thickness making more trigger points available as well as making a slide for life situation possible in places.

Huntington Ravine has a similar mix of surfaces and climbers will find it necessary to be flexible in their micro-route finding as they pick their way up a gully.  Escape Hatch is currently Low hazard with not much snow to avalanche, while South and Odell Gully are not far behind with a low side of Moderate rating.  Pinnacle through North gully have a greater area of bed surface and have large enough areas of new windslab that climbers should use caution when climbing these gullies as a human triggered avalanche is possible in select steep features and lee aspects.

Chris bulleted some key points yesterday which I have updated and carried over below:  

Main points to remember in the field today:  1. 3.3” of snow fell on Monday with high SW winds creating some instabilities on aspects with a NE facing component. 2.  Since Monday afternoon winds shifted to the W and WNW peaking midday Tuesday with an additional 1.8”of snow.   These Tuesday conditions developed new slabs mostly on E facing slopes.  3.  New loading will came close to shutting down yesterday morning as winds dropped to 15-20mph focusing our main concern on slabs created on Monday and Tuesday.  Some of these should be solidly in the Moderate rating. 4. 1/2″ of new snow in the last 24 hours has obscured many visual clues but not improved riding conditions. 5. Expect variable conditions so be ready for constant changing surfaces under foot depending on where you travel.  From sweating over a long slide on icy terrain one second, to triggering an avalanche the next, plan on encountering different hazards in both Ravines.

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 8:55a.m. Thursday 2-14-2013. 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

2013-02-14 Print friendly

 

Avalanche Advisory for Wednesday February 13, 2013

This advisory expires at Midnight Wednesday 2-13-2013

Tuckerman and Huntington Ravines 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.

Over the past couple of days the summit received 5.1” (12.5cm) of new snow on winds coming from the SW to the NW.  1.8” (4.5cm) of this came yesterday on an increasing wind from the W peaking at 96mph (154kph) during the late morning and afternoon.  New slabs that have developed recently are a mix of new stellars, graupel, and fragments of redistributed crystals from alpine zones broken up by high W and WNW winds.  This mixture was witnessed in Huntington and at Hermit Lake this morning.  Currently we still no visibility due to clouds, fog and a bit of blowing snow that has been the mainstay since Monday morning.

Peak instability was likely reached yesterday afternoon during maximum loading due to high winds and new snow.  Strong protected lee areas under the Tuckerman Headwall, Lip and Sluice and down low in Huntington’s Central, Pinnacle, Odell and South gullies were areas that likely picked up the most snow being more sheltered from W and WNW winds.  If these slabs stayed in place and did not avalanche they are the spots I would expect to be on the upper end of the Moderate danger rating today.  Additional slab development today will be quite limited as wind velocities are forecasted to fall down to 20mph (32kph) on the summits.  Because of this the vast majority of unstable slabs you will find in the Ravines developed over Monday and Tuesday.  In addition to areas of soft and hard slab you will still likely find plenty of old icy surfaces blown clean by high winds from the SW, W and NW.  Therefore, be ready to find a high degree of spatial variability on the spectrum from rock hard old surfaces to pockets of soft unstable slabs.  Until visibility improves with a dropping wind later today negotiating the best travel route to avoid instabilities will be difficult.   

Main points to remember in the field today:  1. 3.3” of snow fell on Monday with high SW winds creating some instabilities on aspects with a NE facing component. 2.  Since Monday afternoon winds shifted to the W and WNW peaking midday Tuesday with an additional 1.8”of snow.   These Tuesday conditions developed new slabs mostly on E facing slopes.  3.  New loading will come close to shutting down this morning as winds drop to 15-20mph focusing our main concern on slabs created on Monday and Tuesday.  Some of these should be on the upper end of the Moderate rating. 4. Expect variable conditions so be ready for constant changing surfaces under foot depending on where you travel.  From sweating over a long slide on icy terrain one second, to triggering an avalanche the next, plan on encountering different hazards in both Ravines.

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 8:29a.m. Wednesday 2-13-2013. A new advisory will be issued tomorrow.

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

2013-02-13 Print Version

Avalanche Advisory for Tuesday, 2-12-2013

Expires at 12:00 midnight, February 12, 2013.

All forecast areas of Tuckerman and Huntington Ravines will have Considerable avalanche danger.  Natural avalanches are possible and human triggered avalanches are likely. The only exceptions to the Considerable rating are the Lower Snowfields and the Little Headwall, which have Low avalanche danger. In these areas, natural avalanches are unlikely and human triggered avalanches are possible.

There are two important factors to the avalanche advisory today. The first is related to snow that fell and was blown around yesterday, the second is the additional wind loading that may take place during the day. These factors each affect different aspects, so your choice of routes  and ability to safely navigate through various snow conditions will be critical to avoiding avalanches. Avalanche danger will be increasing today.

Yesterday, Joe and I thought we could make a quick trip up through Tuckerman to take a look at what appeared to be an crown line high up on the Lion Head ridge. As we got into the Bowl, snow began falling at a good rate and SW winds began to crank. When we topped out of the Lobster Claw, it was pretty clear that we weren’t going to be taking any extra time to look around. The strong SW winds were nearly knocking us to our knees, so you can imagine what it was like for all the snow above treeline that was exposed to the winds. Snow was being transported across the flatter terrain and depositing in steep lee aspects such as Hillman’s, Left Gully, the Chute, Odell Gully, and South Gully. Stability issues leftover from yesterday will most likely be found in aspects ranging from N-facing to E-facing, as well as sheltered pockets in other areas. Overall yesterday, the summit recorded 3.3″ (8cm) of new snow before midnight and a little more since then. Our snowplot at Hermit Lake had 3″ (8cm) as well.

The weather forecast for today is calling for 1-3″ (2.5cm to 7.5cm) of additional upslope snow, thanks to an upper level trough, favorable wind directions, and low level moisture in the atmosphere. Winds today will be blowing strong from the NW, at 60-80mph (95-130kph) with higher gusts. These shifting winds will be able to find snow where the SW winds couldn’t, and it will be blown into the ravines. How much new snow we will actually receive is little more uncertain. We’re  rating the ravines today on the hope that we’ll get 2 or 3″ of new snow, which will mix with the older snow being relocated to new homes on steep lee aspects facing to the S, SE, and E. These slopes are starting the day in the Moderate range, but will rise into Considerable will additional slab development. As time passes, the possibility of naturally triggered avalanches will increase from “unlikely” to “possible,” which is to say we’ll be moving from Moderate to Considerable avalanche hazard.

The Lower Snowfields and Little Headwall are currently rated at Low danger. If we were in December instead of February, we’d be saying they are “not posted due to an overall lack of snow in these areas.” In reality, there is little quality recreational opportunities in these areas at this time. The Little Headwall resembles an ice climb. It is not a good option for descending out of the Bowl. The Lower Snowfields are still a tangled mess of shrubbery, but they are exposed to avalanches coming from slide paths above. Hillman’s Highway, in case you were wondering, is still a mess in the lower half. The January rain created a slush path in the lower third which is now a refrozen mix of old slush, sand, gravel, and tree branches.

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 8:09 a.m. February 12, 2013. 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

2013-02-12 Print Friendly

Avalanche Advisory for Monday, February 11, 2013

Expires at midnight 2-11-2013

Tuckerman Ravine has MODERATE and CONSDERABLE avalanche danger. All forecast areas have Considerable avalanche danger except the Little Headwall and the Lower Snowfields which have Moderate danger.  Natural avalanches are possible and human triggered avalanches are likely in Hillmans Highway, Left Gully, Chute, Center Headwall, Sluice, Right Gully and Lobster Claw. Natural avalanches are unlikely but human triggered avalanches are possible in the Little Headwall and Lower Snowfields.

Huntington Ravine has CONSIDERABLE avalanche danger. Natural avalanches are possible and human triggered avalanches are likely in all forecast areas. Careful snowpack evaluation, cautious route finding and conservative decision making are essential for those traveling in Huntington today.

Avalanche danger will be increasing through the day as 3-6” of snow, possibly mixed with sleet later on, fall in 55-75mph southwest winds.

Overcast skies this morning allow another look at the snowpack in the Ravines before a warm front reduces visibility with lowering clouds and blowing snow later today. The forecasted snowfall will add to our existing avalanche problem in areas previously loaded by the most recent Nor’easter and create new windslabs in areas that were scoured down to old surface during the same storm. Additionally, light snow deposited in the many lee areas and nooks and crannies of the alpine zone will be picked up by the increasing winds and dropped into the start zones of areas like Hillmans Highway, Left Gully, the Chute and Center Headwall in Tuckerman Ravine and South Gully, Odell, Pinnacle and Central Gully in Huntington Ravine.  Recall that these areas and others which face generally North and East were scoured out during Friday and Saturdays Nor’easter to the point that old surface rain crust will form today’s bed surface in those areas. The incoming snow, which will increase in density, will form sensitive windslabs with the dreaded “upside-down” configuration. While wind speeds will be high enough for loading in North and northeast aspects with new and transported snow, it will not reach speeds necessary to scour out more Southerly aspects. These East through South facing aspects will crossload strongly with the new snow adding weight to existing windslabs and cornices currently found out the top of areas like Right Gully, Lobster Claw, Yale and Damnation.

Those motivated to tangle with the white dragon had better be near the top or out of any gully by early afternoon. Avalanche issues today are complex and will only become more so as this storm develops.  Travel in avalanche terrain is not recommended for climbers or skiers without extensive experience making route finding decisions in avalanche terrain in unstable snow.  Speed will be paramount for climbers or ski mountaineers in the Ravines today.  If your pack weighs much more than 25 lbs or if all of the gear you are carrying is shiny and new, you should rethink your plans for traveling in avalanche terrain today. Those with solid judgment and impeccable technical skills could scoot up and down steep terrain this morning before said dragon descends looking for victims. This morning, our snowpack is generally more stable than yesterday so risk tolerant individuals could find some adventure if they carefully consider the instabilities Chris wrote about in yesterday’s advisory. The choice is yours.

Those intending to summit via the Lion head (Tête de Lion) trail should be prepared for increasingly challenging travel conditions as winds ramp up and visibility degrades. Remember that the trail is a steep mountaineering route and recent snow will make the rock step easier while deeper and drifted snow above treeline may slow your pace.

 

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 8:42a.m. 2-11-2013. 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

2013-02-11 Print friendly