Avalanche Advisory for Tuckerman and Huntington Ravines

Posted 8:30 Thursday 3-31-2011

Tuckerman Ravine has Moderate and Low avalanche danger.  The Lobster Claw, Sluice, Lip, Center Bowl, the Chute and the Lower Snowfields have Moderate avalanche danger.  Natural avalanches are unlikely and human-triggered avalanches are possible.  Right Gully, Left Gully, Hillman’s Highway, and the Little Headwall have Low avalanche danger. Natural and human-triggered avalanches are unlikely in these areas.  Watch for unstable snow on isolated terrain features.

Huntington Ravine has Low avalanche danger. Natural and human-triggered avalanches are unlikely.  Watch for unstable snow on isolated terrain features.

Even though the sun finally popped out yesterday, winds kept slopes cool allowing some instabilities from last weekend’s storm to linger.  This event gave us about a foot of low density snow which has been transported since on NW winds.  Loading diminished to become insignificant on Wednesday as we enter a brief lull until tomorrow’s weather maker. The main areas of concern continue to be the Lip and the Center Bowl followed by their outliers, namely the Sluice and the Chute. The Lobster Claw has stable snow along the climber’s far right side which is also where most of the gully’s traffic has been.  The upper reaches of the climber’s right fork and the entire left fork from the bottom of the “Y” have more snow of concern and is the cause for the Moderate rating.  Brian and I were impressed with the amount of snow the Lower Snowfields picked up during the prolonged loading event following the weekend storm.  It is on the lower end of the Moderate rating, but not quite down to Low.  You will find a lot of spatial variability in this diverse forecast area that stretches from Hillman’s Highway to the Little Headwall.  Hillman’s Highway has pockets of snow to be aware of particularly in some isolated locations in the climber’s right hand fork.  In Right gully the climber’s left wall, which has an easterly aspect, have some isolated terrain features to watch.

The big news is the impending Winter Storm bearing down on the Northeast.  The National Weather Service (NWS) has issued a Winter Storm Warning from 2 am Friday morning until 8pm.  This Nor’easter has good agreement between models so we are confident we are in for a wallop. Initially snow will be lighter density with low wind speeds from the East.  Wind speeds will ramp up a bit before the shift towards the N occurs, likely moving snow from the earlier thin blanket.  I would expect cross-loading on W and SW slopes to occur during this period.  As daylight appears tomorrow snowfall intensity will increase, snow density will get heavier, and winds will increase to 60+mph (97kph) as they begin to shift and come from the NNW.   Total snowfall may surpass 12” (30cm) at higher elevations.  The NWS is forecasting 8-15” (20-38cm) for the region.  You will likely see a number of “High” ratings tomorrow with the potential for a Considerable or two, or even…… yes the “E” word…..Extreme.  If the system continues to pan out as expected travel in avalanche terrain will not be recommended tomorrow.  I would also expect lingering avalanche issues into the weekend with some elevated danger ratings.

The Lion Head Winter Route is filling in and evidence of recent avalanche activity can be found on both sides of the route.  The best line up the ridge is marked with bamboo poles.  Stay on this path to avoid the more significant avalanche terrain on either side. Saturday night April 2nd will be the last night the Harvard Cabin will be open this season.  After that, the only place you can camp on the east side of Mt. Washington will be at Hermit Lake Shelters in Tuckerman Ravine.

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.

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

Printer Friendly Advisory

Avalanche Advisory for Tuckerman and Huntington Ravines

Posted 8:00 a.m., Wednesday, March 30, 2011

Tuckerman Ravine has Moderate avalanche danger.  Natural avalanches are unlikely and human-triggered avalanches are possible.  The only exceptions to this rating are the Little Headwall and Left Gully which have Low avalanche danger. Natural and human-triggered avalanches are unlikely in these areas.  Watch for unstable snow on isolated terrain features.

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

It has been a dynamic week with more weather expected to keep the show going.  Today and tomorrow morning are forecasted to bring a welcome lull in the active weather pattern before a Nor’easter impacts the region on Thursday night and Friday.  Today’s stability concerns are lingering wind slabs from last weeks 11.8″ (30 cm) of snow and a prolonged period of winter weather punctuated by relentless winds.  The mountain has been punishing lately and avalanche activity has been abundant.  The last storm, which was actually an unforecasted up slope snow event, produced our largest avalanche of the season in Tuckerman and numerous avalanches in terrain that hasn’t really had avalanche activity this season.  Natural avalanche activity calmed down on Sunday but we have had two natural avalanches since then that we know of.  The most recent of these occurred on Monday night when a sluff from the Duchess triggered a small slab in the Lower Snowfields.  Trace amounts of snow have fallen over the past two days which may have formed some softer slabs in strong lee areas of NW winds.  Of all the stability issues today, these will be the easiest to trigger but of less consequence than the hard slab that dominates Tuckerman.  The hard slab provides good bridging over weaker layers below and it could be challenging to trigger an avalanche.  If someone were to find a “sweet spot” that causes failure and fracture in the hard slab, expect a nasty avalanche to ensue.  Strong and sustained winds have created a mosaic of snow conditions that will require you to stay alert to changing conditions.  In Huntington, this mosaic exists but isn’t as complex as Tuckerman.  For the most part, Huntington has been pounded into a stable state by recent winds.  Tuckerman offers some options for the avalanche savvy traveler and clearing conditions should make it easier to make sense of what is going on.

We look forward to taking advantage of the clearing trend to better evaluate the current avalanche issues.  Expect similar stability ratings tomorrow with potential for some areas posted at Moderate to move down to Low.  As mentioned, we are starting to have more confidence that this next storm will bring accumulating snow to the mountains Thursday night and Friday.  Expect elevated avalanche danger to spill over into the weekend.  We will keep you posted on this in the coming advisories and in Friday’s weekend update to help you with your trip planning.

The Lion Head Winter Route is filling in and evidence of recent avalanche activity can be found on both sides of the route.  The best line up the ridge is marked with bamboo poles.  Stay on this path to avoid the more significant avalanche terrain on either side.

Saturday night will be the last night the Harvard Cabin will be open this season.  After that, the only place you can camp on the east side of Mt. Washington will be at Hermit Lake Shelters in Tuckerman Ravine.

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.

Brian Johnston, 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 8:20a.m., Tuesday, March 29, 2011

Tuckerman Ravine has Moderate avalanche danger today.  Natural avalanches are unlikely and human-triggered avalanches are possible.  The only exceptions to this rating are the Little Headwall and Left Gully which have Low avalanche danger. Natural and human-triggered avalanches are unlikely in these areas but you’ll need to watch for instability in isolated areas.

All forecast areas in Huntington Ravine have Low avalanche danger.  Natural and human-triggered avalanches are unlikely but you’ll need to watch for instability in isolated areas. 

Yesterday’s forecast for a small amount of snowfall didn’t hold true and I wish I could say it was because we had a large amount of snowfall instead.  Unfortunately such was not the case and I’d be hard pressed to call what we received even a trace.  There were in fact snowflakes in the air off and on throughout the day but when I headed down the hill in the afternoon there wasn’t a hint of new snow at Hermit Lake.  Needless to say we did not reach our forecasted avalanche danger ratings.  The summit did record a trace of snow yesterday and blowing snow continued to find its way into every hourly observation as it has for the past four days.  As a result drifting and wind transport continued to occur but most of this was limited to mid and lower elevations.  The strong winds continued to pummel the snow in upper elevations and I expect to see lots of scouring and windpack once this darn cloud cover lifts.  We plan to get out in the field later today and figure out how much energy is left in the steel slabs that surround us.  If you’re venturing into avalanche terrain today expect to find a variety of surface conditions with nearly all of them hard and/or icy.  Most of the old icy crust has been buried at this point but you may find patches peeking out here and there.  Have your ice ax ready if you’re traveling on this surface as it is quite slick and sliding falls are a concern.  Hard slab and wind-pack conditions dominate most areas and afford some great cramponing on squeaky Styrofoam snow.  Your ice ax will come in handy here as well.  Should you come across softer snow it should raise a red flag as it will likely be medium hardness windslab that is more reactive to a human trigger. Likely locations include the Lip, Sluice and any other areas that are well protected from NW winds. 

The trend over the next couple of days is for warmer and less windy conditions. Although today we’ll continue to deal with thin cloud cover the next couple of days should bring more sun to the snowpack.  The hard windslab and exposed old surface that dominate steep slopes will appreciate that sun almost as much as me! It’s still a ways out but there appears to be a system with some potential headed our way for the weekend.  The potential for what remains to be seen.  Stay tuned!

The Lion Head Winter Route is filling in and evidence of recent avalanche activity can be found on both sides of the route.  The best line up the ridge is marked with bamboo poles.  Stay on this path to avoid the more significant avalanche terrain on either side.

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

Avalanche Advisory for Tuckerman and Huntington Ravines

Posted 8:10 am, Monday, March 28, 2011

 

Tuckerman Ravine and Huntington Ravines will have Considerable avalanche danger todayNatural avalanches are possible and human triggered avalanches are likely. There are two exceptions to this rating.  The Escape Hatch in Huntington Ravine will have Moderate avalanche danger today.  Natural avalanches are unlikely and human triggered avalanches are possible in this area.  The Little Headwall in Tuckerman Ravine will have Low avalanche danger.  Natural and human triggered avalanches are unlikely in this area. 

 Today is starting much like yesterday with clear blue skies up high, summit temperatures in the negative numbers (F), and winds that are howling out of the WNW at sustained speeds of 65-80mph (105-129kph).  One notable difference is that the air mass has slightly more moisture in it than 24 hours ago and as a result a thin blanket of clouds is hovering just above Hermit Lake.  This moisture is driving today’s rise in forecasted ratings as up-slope snow showers are expected in the higher terrain.  Accumulations are notoriously difficult to predict under these conditions but the Observatory staff is forecasting 1-3” (2.5-7.5cm) while the National Weather Service is calling for 2-4” (5-10cm).  Both are in agreement that winds will remain out of the NW but should decrease to 55mph (89kph) later in the day.  Such conditions should create new windslab of concern primarily on slopes with SE aspect such as the Center Bowl through Right Gully in Tucks and the top part of South through Yale Gully next door in Huntington. 

 We are beginning the day with better overall stability than we had yesterday and the day’s rating are mostly based on the changes expected with today’s forecasted weather. Arctic temperatures have allowed energy to remain in the snowpack but all exposed areas have been getting hammered by the relentless wind.  The result is a mix of scouring, windpack and very hard windslab that would not be very reactive to human triggers except where it is thin.  Slopes that have a higher degree of protection from WNW winds are the exception and Brian noticed evidence of new avalanche activity on his way into Huntington that wasn’t there yesterday morning.  The slope that failed is in an area that we call Broken Leg Gully and is located well down the ridge from Escape Hatch.  Unfortunately the Bowl has been obscured by a thin cloud layer all morning and we’d really like to see if the Lip and/or Sluice ripped out overnight as well.  Aside from the new snow coming in there are a number of areas in Tuckerman that are on the cusp between Low and Moderate this morning.  Hillman’s Highway and Left Gully were both candidates for a drop to Low today but the weather forecast isn’t allowing that to happen.

As mentioned earlier, arctic conditions continue to grip the mountain and yesterday was pretty punishing.  Few people tested their luck above treeline and the smarter crowd hung low and sipped tea out of their thermoses.  Today is going to be similar.  Dropped or unattended gloves blow away in two shakes of a lamb’s tail.  Frostbite happens quicker than you realize and hypothermia impairs your ability to recognize when the going has gotten too rough.  Even if you’re going for a walk on the lower part of the mountain carry extra gear, travel in pairs, and don’t hesitate to head down to the visitor center for a mug of cocoa.   If you do go above treeline the Lion Head Winter Route is filling in and evidence of recent avalanche activity can be found on both sides of the route.  The best line up the ridge is marked with bamboo poles.  Stay on this path to avoid the more significant avalanche terrain on either side.

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

Avalanche Advisory for Tuckerman and Huntington Ravines

Posted 8:30 am, Sunday, March 27, 2011

Tuckerman Ravine: Sluice, Lip and Center Bowl have Considerable avalanche dangerNatural avalanches are possible and human triggered avalanches are likely. All other forecast areas in Tuckerman Ravine have Moderate avalanche danger.  Natural avalanches are unlikely and human triggered avalanches are possible.

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

Today’s weather makes it feel like February is just around the corner, not April!  A very winter like weather pattern will continue to bring challenging conditions to the mountains today.  Summit temperatures are forecasted to max out around 0F (-18 C) and NW winds will remain strong with speeds between 60 and 80 mph (97 ad 129 kph) through the day.  The mountain has cleared out and we have been able to see some of the aftermath from recent avalanche cycles.  There is a pretty big crown line on the south side of Tuckerman Ravine and remnants of avalanche debris, flanks and fracture lines in numerous other areas.  Last night winds ramped up beyond their forecasted speeds with periods of steady 90 mph (145 kph) winds and gusts over 100 mph (161 kph) for several hours.  This caused avalanche activity to work its way down to lower elevations including in Raymond’s Cataract, on the Lion Head Summer Trail and a gully located down the ridge from the Escape Hatch in Huntington Ravine.   These high winds also scoured out most of Huntington Ravine which is why it is rated Low today but there are still pockets of concern such as the lowest sections of Pinnacle and South.  Tuckerman Ravine is a different story.  The primary concern here is the Lip and Sluice. The evidence of a recent avalanche on a neighboring slope, the absence of a fracture line in these areas and on-going wind loading is all the information I need to stay the heck away from these forecast areas.  Expect unnerving conditions that fall within the Moderate rating in the Lobster Claw, Right Gully and the Chute.  Left Gully and Hillman’s Highway fall on the lower end of the Moderate rating.  In these locations, wind scouring and packing has left plenty of variability in the snowpack but you may find some parts that are still unstable, especially in the mid-sections of these two gullies and the top climber’s right of Hillman’s.  The Lower Snowfields are variable but I would expect to find some pretty reactive snow in this forecast area in protected areas under the buttresses.  As for the Little Headwall, you can easily navigate your way though here without too much concern; however, there is a bunch of wind deposited snow on the snowfields at the top of it.

The Lion Head Winter Route is filling in and evidence of recent avalanche activity can be found on both sides of the route.  The best route is marked with bamboo poles.  Stay on this path to avoid the more significant avalanche terrain on either side.

Snow showers are forecasted to move in this afternoon and linger through tomorrow.  At this time, we are not expecting much in the way of accumulation but we will have to see if the mountain can work its magic to give us another 12″ like last week’s snow showers.  Wishful thinking?

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.

Brian Johnston, 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 7:45 am, Saturday, March 26, 2011

Tuckerman Ravine: Sluice, Lip, Center Bowl and Chute have HIGH avalanche danger.  Natural avalanches are likely and human triggered avalanches are very likely. Travel in avalanche terrain is not recommended. All other forecast areas in Tuckerman Ravine, with the exception of the Little Headwall, have Considerable avalanche danger.  Natural avalanches are possible and human triggered avalanches are likely.  The Little Headwall has Moderate avalanche danger.  Natural avalanches are unlikely and human triggered avalanches are possible.

Huntington Ravine: All forecast areas in Huntington Ravine have Considerable avalanche danger.  Natural avalanches are possible and human triggered avalanches are likely.

Winter’s talons are keeping a firm grip on the mountain this weekend.  Numerous avalanche issues, strong winds and temperatures struggling to reach 0F (-18C) on the summits will make you forget that we celebrated the first day of spring last week.  Today is a heads up day for anyone venturing into avalanche terrain.  The mountain picked up a surprise 11.8″ (30 cm) of new snow over the past two days and W and NW winds have been transporting it into the ravines resulting in natural avalanche activity.  The new snow density is light, around 5%, and it has proven to work effectively with the wind to create very reactive wind slabs.  While visibility was limited yesterday, we were able to see some impressive crown lines from recent avalanches, including in terrain that doesn’t usually avalanche.  While additional snowfall will be limited today, we are expecting a notable increase in winds.  They will remain out of the NW and climb into the 55 to 75 mph (88 to 120 kph) range with higher gusts.  These will be the strongest winds the new snow will have endured so we expect significant wind loading to continue today.  Natural avalanche activity remains a significant issue.  You may notice that we dropped many areas down to Considerable from High.  This is because we think peak instability has passed; however, we think the definition of Considerable reflects our expectations of the snowpack very well:  Natural avalanches are possible and human triggered avalanches are likely. We left some areas in Tuckerman Ravine at High because we think it is likely that these forecast areas will continue to avalanche when the winds increase.  One thing to keep in mind is that we could have some pretty substantial avalanches today, including in areas rated at Considerable.  Walking into the base of either Ravine will put you in the run-out of multiple paths.

The Lion Head Winter route is filling in and avalanche terrain exists around this route.  Chris marked the best route with bamboo poles yesterday.  Stay on this path to avoid the more significant avalanche terrain on either side. If you were hoping for a mellow saunter up to the summit, you better plan your trip for another day.  Today’s conditions will test your winter mountaineering skills due to poor visibility, strong winds and cold temperatures.  This stretch of weather will continue tomorrow with slightly higher winds and similar temperatures.  While some areas may come down a rating tomorrow, expect similar avalanche problems to persist.  Cold temperatures won’t allow for much settlement in the 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.
  • This advisory expires at midnight. A new advisory will be issued tomorrow.

Brian Johnston, 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 8:28am, Friday 3-25-2011

Tuckerman and Huntington Ravines 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 only exception to this is the Little Headwall which has Considerable avalanche danger.  Natural avalanches are possible and human triggered avalanches are likely.

Once again the mountains are giving weather forecasters a little surprise as they are forcing quite a bit of fluffy accumulation out of the clouds.  As of midnight the summit of Washington reported 7.8” (20cm) of 3.8% low density snow. Snow density increased to 7.8% from midnight to 6am this morning as an additional 2.7” (7cm) fell for a total of 10.5” (26.5cm).  This came in on a shifting wind beginning out of the E, moving to the N, and eventually coming from the NW Thursday afternoon.  Wind speeds began very light upon precipitation initiation putting a thin low density inch or two across the mountain.  I believe this undisturbed blanket will likely be the weak layer contributing to avalanche activity today.  NW winds began to ramp up overnight reaching 35-40mph early this morning.  These velocities are expected to continue today gusting higher occasionally from the NW and WNW.  The very low density snow at temperatures between 5-10 degrees F will load into both Ravines creating a very sensitive touchy soft slab.  I would also pay attention to these instabilities in unusual areas due to the very weak unconsolidated layer I just mentioned.

We have been monitoring the slabs deposited during Monday and Tuesday’s storm over the past couple of days.  These have been on a stabilizing trend, but with the new snow overnight avalanche activity could step down into these slabs which are sitting on a very firm hard crust.  To add to the instability problem is the presence of a very very thin sun crust that developed on a number of south aspects due to some short bursts of intense sun midweek.  This crust now has a low density snow weakness above it with an increasing density slab building on top.

The Bulls-eye points:

  • 10.5” (26.5cm) of new snow which began very light at 3.8% and became heavier albeit still quite dry at 7.8%.
  • Winds began very light around 10-15mph as snow began and increased overnight gusting to 45mph this morning.
  • Low density snow coupled with moderate wind velocities from the NW and WNW will generate very touchy soft slabs on a variety of aspects and slope angles.
  • Additional snow is expected today as upslope conditions exist giving us perhaps 2 or 3 additional inches
  • Expect numerous soft slab avalanche cycles as new snow quickly reloads in strong lee areas.

With the information I have right now I expect HIGH avalanche danger to exist into the weekend.  Increasing winds on Saturday from the NW at 45-50mph in the morning to over 70mph in the afternoon will bring copious new snow into avalanche terrain.  The touchy nature of new slabs may generate snow instabilities on the upper section of the winter Lion Head route above treeline.  It will be important to stay on the route to avoid the majority of these issues.  However, it is still possible unstable snow will exist on the route.  It will be important to have good assessment skills.  This is particularly true tomorrow as winds increase and more people acting as triggers will be out for the weekend.  Be sure to check out our Weekend Update later today for more information on the projected issues for Saturday and Sunday.

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.

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

Print Friendly Advisory

Avalanche Advisory for Tuckerman and Huntington Ravines

Posted 7:45a.m., Thursday, March 24, 2011

 

All forecast areas in Tuckerman and Huntington Ravines have Moderate avalanche danger today.  Natural avalanches are unlikely and human-triggered avalanches are possible.  The only exception to this rating is Tuckerman’s Little Headwall which has Low avalanche danger. Natural and human-triggered avalanches are unlikely in this area.

The good news is that today’s weather is not expected to have a significant impact on overall snow stability.  The bad news is that we still have lingering issues from the snow that fell at the beginning of the week. Scattered snow showers are forecasted for today but they’re supposed to be light and spotty with little measureable accumulation.  We’ll likely spend the majority of the day in the clouds with difficult light for picking out visual clues.  Winds are expected to stay below 25mph (40kph) except for an occasional gust so transport of snow will be limited.  They will wrap counter-clockwise from where they now sit out of the E and eventually land in the NW.  This scenario may provide just enough wind from the correct direction to cause the development of very light density windslab high in the start zones of slopes with S and SE aspects.  It may look like powder but if it breaks apart in chunks it is cohesive enough to fail and fracture as a slab. Although the new snow may create small localized issues what drives today’s forecast is really the existing areas of windslab that are fairly widely distributed.  As a quick recap the mountain picked up about 6” (15cm) of cold dry snow at the beginning of the week.  Moderate winds from the S accompanied the snow’s onset before they slid around through the W and then the NW, effectively loading all forecast areas.  The soft slab created was laid down on top of a slick crust in many places so adhesion at this interface was poor.  Temperatures have remained seasonally cold so settlement and bonding have been slow to occur.  Field observations yesterday showed slabs with a significant amount of energy that was still willing to propagate a fracture.  Within the Moderate rating there is a range of conditions to be found in the forecast areas.  The primary concern is for human-triggered avalanches on E to SE aspects such as the Center Bowl through the Sluice in Tuckerman and O’Dell through Yale in Huntington.  These areas developed the thickest windslab from the last storm event and will be in the direct lee of whatever loading occurs today.  As you move away from these aspects you begin to find areas that provide more reasonable options for travel.  As an example Hillman’s Highway has a fair amount of old surface showing and the new snow is easily identifiable. I believe that you can still have a good time out there if you keep your plans flexible, practice safe travel techniques and continually assess stability as you move through the terrain. 

The thick icy crust that provides a poor bonding surface for the snow also creates trouble for visitors where it isn’t buried.  The cramponing may be top notch but the potential for sliding falls is also high where the crust is exposed.  Ice axes are used to self arrest yourself in such conditions and if you don’t have one you have little hope for stopping a sliding fall once it’s begun.  Crampons will get you up there but the ax will make sure you don’t come rocketing down.  And as a quick reminder, snowshoes have no place in steep terrain!  They may have “crampons” on the bottom but they are not designed for anything more than 15 or 20 degree slopes.  Last week we had one incident that resulted from an attempted snowshoe ascent of Right Gully.  Come prepared with the correct equipment and skills for the conditions and terrain!

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

Avalanche Advisory for Tuckerman and Huntington Ravines

Posted 8:15a.m., Wednesday, March 23, 2011

Tuckerman Ravine: The Sluice, Lip, Center Bowl and Chute have CONSIDERABLE avalanche danger. Natural avalanches are possible and human-triggered avalanches are likely.  All other forecast areas in Tuckerman Ravine 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: Central Gully has CONSIDERABLE avalanche danger. Natural avalanches are possible and human-triggered avalanches are likely.  All other forecast areas in Huntington Ravine have Moderate avalanche danger.  Natural avalanches are unlikely and human triggered avalanches are possible.

Heads up out there today!  Don’t let the blue skies and calm winds lull you into thinking the snow is stable. In the past two days, the Summit has received 6.1″ (15.5 cm) of new snow.  This was accompanied by winds that started from the south, then shifted to the SW, W and NW.  Yesterday’s average wind speed up top was 38 mph (61 kph) with a peak gust out of the NW at 60 mph (97 kph).  These winds are not strong by our standards and looking around the mountain today we see a lot of smooth wind slab.  The Lip has a faint hint of a recent fracture line and a jagged fracture line can be seen in the top of the Duchess.  Recent wind deposited snow is hiding any other evidence of recent avalanche activity.  Today’s winds will be shifting to the W and decreasing though the day.  This will make natural avalanche activity less likely but we are quite concerned about the ability of new soft slab to withstand the stress people could put on them.  The new wind slabs are sitting on a hard and icy bed surface and I don’t expect slab hardness to promote stability.  In other words, if you travel in avalanche terrain today, I think you could trigger an avalanche. Good route finding and snow stability skills may open some opportunities; however, most forecast areas don’t have options that avoid new wind slab.  If you play it safe, you can still have plenty of fun today.  The Sherburne Ski Trail is in great shape, the Little Headwall itself has reasonable snow stability and the Lion Head Winter Route will provide you an opportunity to get up above treeline without putting yourself at risk of avalanches.

Clouds will move in later this afternoon and there will be a chance of snow showers.  A weak disturbance will provide the mountains an opportunity to pick up a trace to 2″ of snow tonight and another trace to 2″ tomorrow.  Be sure to check tomorrow’s advisory to see how new snow may be effecting the avalanche danger.

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.

Brian Johnston, 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 8:10a.m., Tuesday, March 22, 2011

Tuckerman Ravine: The Center Bowl, Lip and Sluice have HIGH avalanche danger.  Natural avalanches are likely and human-triggered avalanches are very likely.  All other forecast areas in Tuckerman have Considerable avalanche danger.  Natural avalanches are possible and human-triggered avalanches are likely. The only exception to this rating is the Little Headwall which has Low avalanche danger. Natural and human-triggered avalanches are unlikely.

Huntington Ravine:  All forecast areas in Huntington Ravine have CONSIDERABLE avalanche danger. Natural avalanches are possible and human-triggered avalanches are likely.

This morning’s measurements below the ravines show that we picked up somewhere in the neighborhood of 4” (10cm) of new snow while the Observatory staff recorded about the same up top.  Cold temperatures allowed snow to stay nice and dry but riming on the crystals has caused slightly higher densities than one might expect.  Winds hung out of the S yesterday until around midnight when they made the quick transition to the W and then NW.  Speeds ranged from 30-50mph (48-81kph) for most of this period though they dipped down after dark to less than 20mph (32kph) for a while before rising again in the early morning hours.  This wind pattern primarily loaded slopes with a N aspect though E-facing aspects likely developed new windslab through cross-loading.  Though little new snow is expected today the wind is going to be the key factor in the day’s elevated avalanche danger.  As the day progresses we should see an increase in wind speeds with sustained speeds up to 60mph (97kph) and gusts that push even higher.  These winds will originate from the NW and thus snow will be moved into the ravines from the summit cone, Alpine Garden and Bigelow Lawn.  As this snow blows in it will be deposited on top of the thin layer of unconsolidated fluff that came in during the evening lull in wind speeds.  Although this layer might not be easily discernable by eye or the occasional probing of the snowpack I would expect that stability tests would highlight this weakness within the new storm snow.  Just make sure you’re not doing your stability tests out in one of the gullies!  We expect visibility to remain limited today and our avalanche paths are all fairly well-developed for this point in the season.  This means that avalanches have the potential to run fairly far including across the floors of both ravines.   Areas in the direct lee of today’s winds, such as those rated as High, have the greatest likelihood of avalanche activity and their run-out paths extend across the regular access to most of the other forecast areas.  Of the areas that are rated Considerable today there is a range of conditions.  Some such as the Escape Hatch in Huntington are on the lower end of the rating with the primary concern being the potential for human-triggered slides.  Its next-door neighbor South Gully is quite a bit higher in the Considerable range with a large portion of its start zone in the direct lee of forecasted winds.  Be smart out there and don’t hesitate to grab one of the Snow Rangers if you have any questions.

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