Avalanche Advisory for Wednesday, February 28, 2018

Huntington and Tuckerman Ravines have LOW avalanche danger. All forecast areas have Low avalanche danger. Watch for unstable snow on isolated terrain features.

 AVALANCHE PROBLEM: Wet weather today may reduce stability in wind slabs formed earlier in the week, making wet slab our primary avalanche problem today. This problem is isolated to areas of existing wind slab which can be visually distinguished from the hard, refrozen snow also present at the surface. Timing of peak instability depends directly on the type and timing of precipitation in our terrain. Watch for precipitation falling predominantly as rain to result in the greatest potential for unstable snow. If we receive less rain and more frozen precipitation particles, expect lesser instability of existing slabs. Bear in mind that significant portions of our terrain have firm, slick, refrozen snow at the surface. The risk of a long sliding fall that would be near impossible to arrest may be of greater concern than an avalanche today. Also remember that “Low” avalanche danger does not mean “No” avalanche danger.

 WEATHER: Unsettled weather returns today after sunny and below freezing conditions yesterday. Forecasts are trending towards mixed and wet precipitation that will develop through the day. It appears that the snow level today will be around 5000’, above which a trace to 2” of snow is expected. This translates to modest amounts of moisture falling as rain, freezing rain, sleet, and maybe a little snow in our terrain which is mostly below 5000’ in elevation. This snow level could push up or down and affect the type of precipitation we ultimately see, affecting avalanche conditions as mentioned in the Avalanche Problem section. Mixed precipitation will continue tonight, possibly trending more towards snow, and taper off by tomorrow. Wind will be westerly and peak early today with gusts up to 80 mph on the summit, diminishing this afternoon and tonight.

SNOWPACK: The surface wind slabs formed earlier this week alternate with exposed refrozen snow to make up the surface in our terrain. A series of melt/freeze events has eliminated concerns of deeper instabilities for the time being. These pockets of wind slab that will become less stable with wetting through the day vary in size and character across the terrain. Areas receiving most solar warming yesterday will even hold a sun crust this morning. Pockets of surface snow instability which may increase today suggest that you should not let you guard down, but risk of long sliding falls on the slick snow absent of today’s avalanche problem should be respected as much or more. Two individuals took such falls this past weekend. Both were lucky enough to escape with injuries allowing them to walk out, but such close calls remind us that steep, icy snow slopes demand respect.

The John Sherburne Ski Trail remains mostly snow covered though holds sections of exposed ice and thinly covered rocky ground. It is mostly skiable, but expect sections of challenging variable conditions.

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 Harvard Cabin.
• Posted 8:00 a.m., Wednesday, February 28, 2018. A new advisory will be issued tomorrow.

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

2018-2-28

Avalanche Advisory for Tuesday, February 27, 2018

Huntington Ravine has MODERATE and LOW avalanche danger. Central, Pinnacle, Odell, South, and Escape Hatch Gullies have Moderate avalanche danger. Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully to identify features of concern. North, Damnation, and Yale Gullies have Low avalanche danger. Watch for unstable snow on isolated terrain features.

Tuckerman Ravine has MODERATE avalanche danger. All forecast areas have Moderate avalanche danger. Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully to identify features of concern. The Little Headwall is an open stream and is not rated.

AVALANCHE PROBLEM: Areas of wind slab exist across much of our terrain amid a more widespread refrozen surface of older snow. Size of this wind slab varies across Moderate-rated terrain and is distributed most widely in Central Gully in Huntington and Hillman’s Highway in Tuckerman. Today provides both an obvious and challenging avalanche problem to deal with for those seeking good turns. The new slab in which it is possible for you to trigger an avalanche is easy to see, appearing very white in contrast with the grey old surface. You can avoid the avalanche problem by avoiding travel on or below this visually apparent wind slab. That said, searching for good turns will lead you to travel on the avalanche problem, as the refrozen old surface will be far less than ideal for skiers and riders. Climbers will find good crampon purchase on the refrozen surface and likely be less tempted to travel on wind slab. This slick refrozen surface will easily allow a long sliding fall that most would struggle to arrest. If a stumble or even the smallest of avalanches causes you to lose your footing, you could take a long high-speed slide with potentially serious consequences. Take care, avoid falls and carefully assess consequence when choosing terrain.

WEATHER: Warmer, though below freezing temperatures, and W summit wind around 50 mph prevailed yesterday as skies trended toward clearing. We should have minimal cloud cover today with temperatures approaching 20F on the summit and remaining below freezing in our terrain. Westerly wind is forecast to increase through the day and ultimately gust to 80 mph this afternoon on the summit. A cold front arriving late tonight will bring back a snowy pattern to the mountain, with potential for several inches of new snow tomorrow and snowfall continuing into tomorrow night.

SNOWPACK: The wind slab that formed late Sunday, and into Monday morning, is our only stability concern at the present time. Our deeper snowpack has seen successive melt/freeze events, and the hard, refrozen surface on which our pockets of wind slab sit, does not hide deeper layers posing much avalanche concern. Significant wind transport over the last few days has created great variability in distribution and character of the new wind slab across our forecast area. Further, select aspects which saw greatest exposure to solar warming yesterday will hold a melt-freeze crust on the wind slab. As mentioned above, realize that the hunt for good skiing in these variable conditions will lead you to the avalanche problem and that there is a lot of icy, refrozen snow at the surface.

The John Sherburne Ski Trail holds a wide variety of conditions, including significant exposed ground, areas of water ice, thinly veiled rocks, and also some skiable snow. While mostly skiable it is certainly in challenging condition.

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 Harvard Cabin.
• Posted 8:20 a.m., Tuesday, February 27, 2018. A new advisory will be issued tomorrow.

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

2018-02-27

Avalanche Advisory for Monday, February 26, 2018

This advisory expires at Midnight.

Huntington will have CONSIDERABLE and MODERATE avalanche danger today. Central, Pinnacle, Odell, South, and Escape Hatch have Considerable danger. Natural avalanches are possible and human-triggered avalanche are likely. North, Damnation, and Yale have Moderate avalanche danger. Heightened avalanche conditions on specific terrain features.

Tuckerman Ravine will have CONSIDERABLE avalanche danger today. Dangerous avalanche conditions exist. Natural avalanches are possible and human-triggered avalanche are likely. Careful snowpack evaluation, cautious route-finding and conservative decision-making are essential.

AVALANCHE PROBLEM: Today’s avalanche problem is wind slab. This hazard will increase slowly through the day as wind continues to transport snow from the fetch into avalanche terrain. Areas of largest concern are those in the direct lee of W and NW wind as those will see the most loading today. Also of concern would be gullies that were in the lee of yesterday’s S and SE wind. Areas rated Moderate today had less developed bed-surfaces prior to yesterday.

WEATHER: Snowfall began Sunday around 8:30am when the Summit was recording a temperature of 7F and SE wind with speeds around 35mph. As the day progressed, temperatures warmed to the high-teens and wind shifted S with speeds increasing by about 10mph. A period of freezing drizzle was observed during the last hour of precipitation in the late afternoon. Total accumulation on the Summit was 5” of snow with a snow water equivalent of 0.56” while Hermit Lake recorded 2.4” of snow with a SWE of 0.47”. Today, temperature will fall from the teens into single digits and wind will shift to the NW and stay in the 50-70mph range. We may also see up to 2” of upslope snow arrive through the day.

SNOWPACK: Before snowfall began yesterday, our refrozen snowpack posed no avalanche concerns. Rather, that hard, icy snow will now provide a slick bed surface for developing wind slab. Wind slab that began forming yesterday and will continue to develop today will likely have an upside-down structure due to warming temperatures as snow arrived. With wind shifting from SE yesterday all the way to NW later today, multiple aspects will see direct loading as well as cross-loading. Visibility into avalanche terrain this morning is minimal, but enough to see signs of wind transport as well as scattered areas of old surface low in avalanche paths. This leads us to believe that the combination of wind speed and snow density will generate greatest wind slab development high in start zones. As visibility may prevent seeing these start zones, it may be hard to evaluate this from a safe distance. Also keep in mind that several gullies with a northerly aspect that we do not forecast may have significant wind slab development and potentially could run into or across other slide paths. This is particularly true on the Boott Spur ridge.

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 Harvard Cabin.
• Posted 8:00 a.m., Monday, February 26, 2018. 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

2018-02-26

Temporary Harvard Cabin Closing

Harvard Cabin will be temporarily closed mid-week due to a staffing shortage. The cabin will be open Friday and Saturday nights. This closure includes tenting outside the cabin. For those interested in overnighting in the Cutler River Drainage, you may do so at Hermit Lake Shelters. We will provide updates to this closure on our website or you may contact the AMC Pinkham Notch Visitor Center at (603) 466-8116 to see if there is availability.

Long Sliding Fall, February 24, 2018

At about 1:00 PM, a climber took a long sliding fall while ascending Right Gully in Tuckerman Ravine. The subject lost their footing on very hard, icy snow and was unable to self-arrest with an ice axe. The fall occurred near the top of Right Gully and the resulting high speed slide was halted below the gully by exposed bushes and rocks. The fall totaled approximately 300 vertical feet. The subject was able to walk away from the accident, traveling on foot with help of their climbing partner down to Hermit Lake. The primary injury was presumed to be bruised or fractured ribs from impact with the bushes and rocks that stopped the fall. U.S. Forest Service Snow Rangers transported the subject via snowmobile from Hermit Lake to Pinkham Notch.

The subject and witnesses of this accident unanimously described the event as a close call, all surprised that the outcome was not more serious. The subject was indeed lucky to eventually slide into a generally bushy area as opposed to the many nearby rocks that would have likely resulted in greater injuries. Further, the subject was not wearing a helmet and was very fortunate to avoid hitting their head. The party had climbed Right Gully several times in past seasons and stated that they normally did wear helmets while travelling in steep alpine terrain. Further, they did have experience climbing steep snow and were otherwise properly equipped with mountaineering boots, crampons, and ice axes.

This accident highlights the risk of climbing on steep snow slopes when conditions are hard and icy, making self-arrest all but impossible. Such snow conditions can develop when steep slopes in Huntington and Tuckerman Ravines are snow covered. While firm conditions can inspire confidence for climbers travelling uphill with crampons, it can be incredible difficult to arrest a fall once sliding with any amount of speed. While strong self-arrest skills are crucial for travelers on steep snow slopes, it’s just as important to remember that you may not be able to self-arrest in hard snow. Close calls like this one should remind us to always consider the likelihood and consequences of a long sliding fall when travelling on steep snow. These incidents are common and can easily have more serious outcomes.

Avalanche Advisory for Sunday, February 25, 2018

Huntington Ravine may reach CONSIDERABLE and MODERATE avalanche danger. Yale, Central, Pinnacle, Odell, South, and Escape Hatch gullies may reach Considerable avalanche danger. Careful snowpack evaluation, cautious route finding, and conservative decision making are essential. North and Damnation Gullies may reach Moderate avalanche danger.  Evaluate snow and terrain carefully to identify features of concern.

Tuckerman Ravines may reach CONSIDERABLE and MODERATE avalanche danger. Sluice, Lip, Center Bowl, Chute, Left Gully, and Hillman’s Highway may reach Considerable avalanche danger. Careful snowpack evaluation, cautious route finding, and conservative decision making are essential. Lobster Claw, Right Gully, and the Lower Snowfields may reach Moderate avalanche danger.  Evaluate snow and terrain carefully to identify features of concern. The Little Headwall is an open stream and is not a viable route out of Tuckerman Ravine.

AVALANCHE PROBLEM: All forecast areas this morning are icy and firm with low avalanche hazard. Incoming precipitation will create a widespread wind slab avalanche problem throughout our forecast terrain and increase our avalanche danger to Considerable as the day progresses. The size and tendency of avalanches to release naturally will largely depend on the amount of snow that falls this afternoon. The forecast snowfall of four to six inches of snow in the higher terrain is plenty of snow to create slabs that are capable of knocking you off your feet and carrying you down slope. Combined with an icy bed surface on our steep 35-50-degree terrain, even a small avalanche today can have serious consequences. While winds from the south might seem to target only north facing terrain for wind loading, count on cross-loading and sluffing to load east facing slopes in a similar fashion. If the steep icy base and wind loading aren’t enough of a challenge today, remember that this precipitation will be warming and becoming increasingly dense. This will create an “upside down” snowpack that may begin to act like a wet slab, making the new snow more sensitive to a human-trigger.

WEATHER: Yesterday, no precipitation fell after sunrise as the higher terrain remained mostly in the clouds while temperatures remained below freezing at Hermit Lake. The weather system currently approaching is forecast to bring 4-6” of new snow on wind that should shift from SSE to SW and finally W after dark. Summit wind speed will increase as it wraps around, pushing towards 50 mph this afternoon and likely exceeding that tonight. Temperatures are forecast to trend upwards through this storm with a high near 30F on the summit forecast for this afternoon. As snowfall tapers off late today we may see a changeover to sleet and other mixed precipitation types. Precipitation should end tonight as wind continues to increase and ultimately shifts NW tomorrow.

SNOWPACK: Today’s new snow will fall on an icy refrozen surface. Friday night, precipitation fell in mixed forms and was dominated by ice pellets which contributed to the generally smooth and hard snow surface in our terrain. Beyond providing a slick bed surface for slabs forming today, the existing snowpack does not pose stability concerns. As the day and the storm progresses we will see new slabs develop from the new snow and wind. Varying forecast snowfall totals mean that you should pay close attention to the weather and developing conditions on the ground when making terrain choices. Shifting winds will have the potential to rapidly build touchy slabs on a variety of aspects.

A number of other spring-like hazards exist in our terrain and will become masked by snow through the day. This includes waterfall holes, moats, undermined snow, and rocks that are both in and below our avalanche paths. The John Sherburne Ski Trail holds icy snow with patches of water ice and bare ground.

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 Harvard Cabin.
• Posted 7:45 a.m., Sunday, February 25, 2018. A new advisory will be issued tomorrow.

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

2018-2-25

Avalanche Advisory for Saturday, February 24, 2018

Huntington Ravine and Tuckerman Ravines have LOW avalanche danger. All forecast areas have Low avalanche danger. Generally safe avalanche conditions. Watch for unstable snow on specific terrain features. The Little Headwall is an open stream and is not a viable route out of Tuckerman Ravine.

AVALANCHE PROBLEM: Small and isolated pockets of new wind slab may exist in our terrain. Minimal new snow overnight has been heavily affected by westerly wind. Most of our terrain remains a hard, refrozen snow surface where avalanches will not be your primary concern. This icy and particularly slippery snow will require appropriate traction devices in any terrain. This means crampons and ice axes on snow slopes and steep trails and microspikes elsewhere. Consequences of a sliding fall on our hard, icy snow remain high, with numerous rocks and other hazards exposed below steep terrain. Appropriate terrain choices and travel skills will help you avoid a high speed fall that could result in serious injury or worse.

 WEATHER: Yesterday brought 0.30 inches of water to the summit which fell mostly as rain, freezing rain, and sleet. Only 0.5 inches of snow was recorded. The little snow we received fell on SW wind that shifted W and ramped up overnight to the current gusts over 100 mph. Temperatures hovered just above freezing at Hermit Lake and just below freezing on the summit late yesterday and last night. It has now turned colder, with a steady summit temperature around 20F forecast today and likely a few degrees warmer in our terrain. Wind and summit fog should decrease through the day. A system moving in late tonight will bring snow and possibly mixed precipitation tomorrow as summit temperatures approach the high 20’s F. This storm which is forecast to become increasingly warm could bring over 6” of new snow, though timing of the forecast changeover to mixed precipitation will ultimately determine new snow accumulation.

SNOWPACK: The mixed bag of precipitation late yesterday and overnight largely fell as rain, freezing rain, and sleet, all of which refroze and now contribute to our hard and icy snow surface. The limited new snow mixed in this storm was heavily transported by wind, and at best amounted to quite small wind slabs that pose little danger to travelers in the alpine. Potential for a long sliding fall on our largely hard and slick snow surface should guide your terrain choices today. Realize that preventing such a fall is essential, as arresting one would be very difficult. Crampons, ice axes, and your ability to use them are essential on snow slopes. Clear skies and sun may briefly and slightly soften snow on south-facing aspects this afternoon, but this window of anything but rock-hard snow will be brief if it happens at all.

 The John Sherburne Ski Trail holds icy snow with patches of water ice and bare ground.

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 Harvard Cabin.
• Posted 7:45 a.m., Saturday, February 24, 2018. A new advisory will be issued tomorrow.

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

2018-2-24

Avalanche Advisory for Friday, February 23, 2018

This advisory expires at midnight.

Huntington and Tuckerman Ravine will have LOW avalanche danger today. Generally safe avalanche conditions exist for all forecast areas.

AVALANCHE PROBLEM: This morning, there is no avalanche problem. Avalanche terrain consists of refrozen snow that with its hard, icy surface, will require the use of crampons and an ice axe to navigate safely. Long sliding falls are currently the greatest danger. Up to 2” of snow is forecast on increasing SW wind in the afternoon and will create areas of wind slab. If we receive the upper end of the forecast snow total, areas in the lee of SW and W wind may exceed the current Low rating.  Be aware of this in Hillman’s Highway, Left Gully and the Chute in Tuckerman as well as Escape Hatch, South and Odell in Huntington. Warming temperatures late may mix sleet and freezing rain into this snow, adding a wet layer to the snow surface. Travelers out late in the day should keep an eye on the sky and be prepared to re-evaluate plans if we receive the upper end of forecast totals.

WEATHER: Yesterday consisted of scattered clouds and a mild NW wind. Temperatures at Hermit Lake and the Summit both saw a maximum in the low 20sF. Lingering high pressure this morning will keep skies largely clear with mild winds and temperatures in the 20sF. Incoming low pressure this afternoon will allow fog to develop on the summits. Current W wind of 25mph will shift to the SW this morning and steadily increase through the day to 50-70mph. Once darkness arrives, the wind will shift to the W and eventually NW by midnight. Snow showers are likely before the temperature rises enough for a transition to mixed precipitation. The amount of liquid precip should remain low, with up to 0.15” by midnight. If we receive the high end of forecast precipitation, we may see 2” of snow.

SNOWPACK: Record-setting temperatures Tuesday and Wednesday were followed by a freeze Wednesday night. This has stabilized our snowpack and created icy surfaces in avalanche terrain. If you venture off-trail in the woods, it may still be possible to post-hole in areas, though above-treeline surfaces should remain solid. Traction is necessary even on flat trails at the moment. The Little Headwall is now an open river and no longer an option for skiing out of Tuckerman Ravine. The Sherburne has stretches of bare ground and water ice. Be prepared to remove your skis at times on the way down.

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 Harvard Cabin.
• Posted 8:10 a.m., Friday, February 23, 2018. 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

2018-02-23

Avalanche Advisory for Thursday, February 22, 2018

Huntington and Tuckerman Ravines have LOW avalanche danger. All forecast areas have Low avalanche danger. Generally safe avalanche conditions exist. The Little Headwall is not rated and is once again an open waterfall with very little snow coverage remaining.

AVALANCHE PROBLEM: Avalanche concerns today have been erased by the record setting warmth and rain over the past several days followed by a return of colder temperatures. An inch and a half of rain early Tuesday and record high temperatures have melted ice and snow in many locations. Avoidable and easily assessed spring hazards have emerged. Today, slide for life conditions will exist on all aspects of steep slopes making an ice axe and crampons and the ability to employ them effectively key tools for safe travel. Running water behind ice climbs in Huntington may have damaged ice or created ice dams that could rupture with a misplaced swing of an ice tool. In Tuckerman Ravine, the Open Book waterfall hole, low in the Lip forecast area, has opened along with the main waterfall hole higher. Both of these waterfall holes have been the scene of fatal accidents so consider giving them a wide berth. Moats and cracks have also developed across the Lip and Center Bowl though remain narrow. All of these hazards should remain on your radar as new snow arrives on Friday. 

WEATHER: The temperature on the summit reached a record high of 48F yesterday which tied the record high not just for the month but for the winter season previously set on Jan 13, 2013. Hermit Lake reached 55F. The warm air temperatures were accompanied by a couple hours of sunshine and high winds before clouds rolled in. Today’s weather is decidedly more wintry, with a current temperature at Hermit Lake of 19F while on the summit it is 15F with a NW wind at 45 mph. Today’s high is expected to reach into the upper teens to low 20’s F. Northwest winds will blow in the 45-60 mph range but diminish through the day to the 25-40 mph range.

SNOWPACK: Free water has mostly drained from the snowpack and cold temperatures are once again bonding grains together in the firm, and now icy, snow of our forecast areas. If you are venturing off trail, or onto seldom used trails, you are likely to encounter post-holing conditions since softer snow doesn’t set up as firmly as the snow in our steeper and more wind hammered terrain. Rocks and ice will dominate most of the length of the Lion Head Winter route making microspikes a good choice for the lower angle sections of that and other similar routes. Even the Tuckerman Ravine trail to Hermit Lake is too slippery for easy walking without some sort of traction devices in your feet. And lastly, in the litany of grim news, the Sherburne Ski Trail is no longer continuous snow with several long sections of previous wind scoured trail now bare grass and dirt.     

The next chance for precipitation comes late Friday when the mountain may receive a few inches of snow but with mixed precipitation at lower elevations.

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 Harvard Cabin.
• Posted 7:45 a.m., Thursday, February 22, 2018. A new advisory will be issued tomorrow.

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

2018-2-22

Avalanche Advisory for Wednesday, February 21, 2018

Huntington Ravine has MODERATE and LOW avalanche danger. Central Gully has Moderate avalanche danger.  Heightened avalanche conditions exist on specific terrain features. All other forecast areas have Low avalanche danger. Watch for unstable snow on isolated terrain features.

 Tuckerman Ravine has MODERATE and LOW avalanche danger. Sluice, Lip, Center Bowl and Chute have Moderate avalanche danger. Heightened avalanche conditions exist on specific terrain features. Evaluate snow and terrain carefully. All other forecast areas have Low avalanche danger. Watch for unstable snow on specific terrain features.

AVALANCHE PROBLEM: Our primary problem will be in the form of the skier or rider initiated loose wet avalanches which are trending towards likely today. Loose Wet avalanches which will be possible for a skier or snowboarder to initiate in steep terrain are our primary avalanche problem. Moderate rated areas held more soft snow at the surface prior to the current warm and wet weather and will be capable of producing large loose wet sluff and point release avalanches. While such avalanches would likely not bury you without a significant terrain trap, they can easily cause a fall and even carry you downhill. Realize that the steep terrain where loose wet activity is most likely to occur is also a particularly high consequence place to take a fall.

 If you venture into the terrain today, be aware that the record warmth is awakening a number of our typical spring hazards. Water flowing beneath the snow surface is creating areas of undermined snow that you could easily break through. Overhead hazards including icefall and to a lesser extent rockfall should be respected. When choosing terrain today, remember that these avoidable hazards have resulted in many accidents, some of them fatal. Don’t neglect to look at safer and equally rewarding options.

 WEATHER: The summit recorded 1.53” of rain during the early morning hours yesterday. The 24 hour high temperature reached 45F at this writing. It is still climbing and has reached 66F already at the base of the Auto Road. Though a down-valley breeze is keeping it cooler in valley locations, a record setting high temperature reading on the summit seems likely as mild air continues to pour into the area. Clear skies and sunshine will speed this warming early before a cold front brings clouds and a tenth of an inch of rain this afternoon and evening. A flood watch is in place for the area due to runoff and melt which serves as a good reminder of the emerging spring hazards. Winds will continue to ramp up from the current 70’s mph on the summit through the day with gusts well into the 90 mph range by sundown. Overnight gusts will reach near 110 mph.

SNOWPACK: Prior to this warmup, our snow surface was a mix of soft wind slab and hard refrozen crust. Rain and warm temperatures yesterday will continue today which will drastically change the upper snowpack. We expect that moisture has fully soaked and then drained from what was wind slab, resulting in less cohesion and minimizing concerns for slab avalanches from this layer. These areas will continue to hold the softest snow with the greatest potential for loose wet avalanches. The former crust surface should provide more dense snow, but could also allow loose wet activity as all snow continues to warm. Expect to posthole to at least your knees in much of our terrain this afternoon. The present hazards and sloppy conditions suggest that our alpine terrain may not be the most rewarding place to enjoy the sunshine today.

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 Harvard Cabin.
• Posted 7:45 a.m., Wednesday, February 21, 2018. A new advisory will be issued tomorrow.

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

2018-2-21

Avalanche Advisory for Tuesday, February 20, 2018

Huntington Ravine has Considerable and Moderate avalanche danger. Central and Pinnacle Gullies have Considerable avalanche danger. Careful snowpack evaluation, cautious route finding, and conservative decision making are essential. All other forecast areas have Moderate avalanche danger. Evaluate snow and terrain carefully to identify features of concern.

Tuckerman Ravine has Considerable and Moderate avalanche danger. Sluice, Lip, Center Bowl, Chute, and Hillman’s Highway have Considerable avalanche danger. Careful snowpack evaluation, cautious route finding, and conservative decision making are essential. All other forecast areas have Moderate avalanche danger. Evaluate snow and terrain carefully to identify features of concern. The Little Headwall is the exception with a Low rating and potential for snow undermined by running water to be a larger concern.

AVALANCHE PROBLEM: Wet Slab is our primary avalanche problem with small slabs in many areas and large slabs in specific areas decreasing in stability through the day. Rain and melt water should wet recently formed wind slabs and percolate to the robust crust beneath them, lubricating this bed surface for avalanches to run on. Moderate rated areas hold significantly less new wind slab and are instead dominated by an old melt/freeze crust snow surface that is again melting. Wet slab avalanches are unlikely in anything but the recently formed wind slab. Peak instability of wet slabs is difficult to predict, but we expect human triggered avalanches to become likely and natural avalanches possible at some point later today. Loose Wet avalanches will be a rising concern as well today and could occur in much of our terrain. If in our terrain today, be on the lookout for overhead hazards in the form of icefall, rockfall, and of course the wet slab avalanches mentioned above. Also watch for weak snow undermined by water running beneath it which you could break through.

 WEATHER: Temperature could push to the upper 40’s F in our terrain today as around 0.5” of rain falls. In total, this warm and wet system looks to be bringing approximately 0.75” of rain. Showers today are forecast to generally taper off tonight and into tomorrow with a chance at clear skies by the end of Wednesday. Our typical westerly wind won’t be absent, blowing in the 60 mph neighborhood for much of the day and increasing tonight. Below freezing temperatures are likely to return by Thursday morning.

SNOWPACK: Our mixed snow surface conditions of wetting wind slab and older melt/freeze will react in distinctly different ways to the rain and warming temperatures today. Wind slab overlying the crust, today’s primary avalanche problem, will become wet and could avalanche on the crust which will become lubricated by percolating rain and melt water. These surface slabs have been formed since Saturday and are largest in the Sluice, Lip, Center Bowl, Chute, and right fork of Hillman’s Highway in Tuckerman Ravine as well as Central Gully in Huntington Ravine. This slab is relatively soft and should increase in sensitivity to a trigger through the day. Our upper start zones and significant portions of our other terrain experienced more scouring over the past few days and hold much more exposed melt/freeze crust from earlier last week. These areas in which the crust is currently softening will offer a safer and likely more enjoyable option for skiers and climbers. Keep in mind that wet loose avalanches will be possible in this snow as the crust becomes fully melted.

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 Harvard Cabin.
• Posted 7:50 a.m., Tuesday, February 20, 2018. A new advisory will be issued tomorrow.

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

2018-2-20

Avalanche Advisory for Monday, February 19, 2018

Huntington Ravine has CONSIDERABLE, MODERATE, and LOW avalanche danger today. Central and Pinnacle have Considerable avalanche danger. Dangerous avalanche conditions exist. Careful snowpack evaluation, cautious route-finding and conservative decision-making are essential. Yale, Odell, South, and Escape Hatch have Moderate avalanche danger. Evaluate snow and terrain carefully; identify features of concern. North and Damnation have Low avalanche danger. Watch for unstable snow on isolated terrain features.

Tuckerman Ravine has CONSIDERABLE, MODERATE, and LOW avalanche danger. Sluice, Lip, Center Bowl, and Chute have Considerable avalanche danger. Large avalanches in specific areas are possible. Dangerous avalanche conditions exist. Lobster Claw, Right Gully, Left Gully, Hillman’s Highway, and Lower Snowfields have Moderate avalanche danger. Evaluate snow and terrain carefully; identify features of concern. The Little Headwall has Low avalanche danger.

AVALANCHE PROBLEM: Today’s avalanche problem is wind slab. Continued wind transport today will add more snow to pre-existing wind slab. Areas of greatest concern are slopes in the lee of W and NW wind (Considerable rated areas) as well as mid-elevations of other aspect, such as Hillman’s and Yale. This wind slab has connected several forecast areas in Tuckerman Ravine, meaning an avalanche triggered in the Lip may include Center Bowl and possibly more. Some areas of steep terrain do not have this wind slab and are wind-scoured to the older, icy snow surface. Crampons and an ice axe will not go amiss on any adventure in steep terrain today.

WEATHER: A total of 5” of snow fell yesterday through the day. While snow was falling, wind shifted between the W and NW and ranged from 40mph to 70mph, with strongest wind speeds recorded around noon. As snowfall died last night, wind speeds diminished and shifted to the SW. This morning, the wind is from the SW and currently blowing 42mph. Wind will likely trend toward the W and should remain in the 40-60mph range for the day. High pressure will keep skies clear for this morning before the incoming warm front approaches. It looks like temperatures should remain below freezing for daylight hours. Fog should develop in the afternoon as the temperature starts to rise with mixed precipitation possible in the evening.

SNOWPACK: Wind slab that formed over the weekend sits on a firm bed surface that has gone through multiple melt-freeze cycles. Yesterday’s 5” of snow fell on increasing wind speeds, creating large areas of wind slab. Wind speeds were at times strong enough to scour areas down to the icy bed surface, though these tend to be in lower portions of our terrain and present themselves with the appearance of gray snow or may even have a reflective sheen with today’s sun. Areas with a northerly and southerly exposure have the most scouring down low and contain firm-looking sastrugi up high, including Damnation and North in Huntington as well as the looker’s left fork of Hillman’s Highway. Places of most concern today will be the Sluice through Chute in Tuckerman and Central and Pinnacle in Huntington. Smooth wind slab dominates these areas and has covered rocks and old crown lines that were visible on Friday, giving an indication to the amount of loading that took place yesterday. Current blowing snow on SW wind of 45 mph is a sign that wind transport has not ended and our fetch still has transportable snow. SW shifting W wind today will allow areas of wind slab to grow in size today. While many gullies have old surface down low due to wind scouring, mid-elevations contain the largest smooth-looking wind slab that could prove touchy to human-triggers today.

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 Harvard Cabin.
• Posted 8:30 a.m., Monday, February 19, 2018. 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

2018-02-19

Local Mountain Weather Course

The White Mountain Avalanche Education Foundation and the NHOC are sponsoring a Mountain Weather Workshop in North Conway, NH. Senior Forecaster and Education Specialist Mike Carmon, of the Mount Washington Observatory, will be teaching topics relevant to avalanche forecasting and mountain travel in the White Mountains.

Topics will include weather variables and measurement, mesoscale and synoptic scale features, case studies on winter storms and forecasting challenges such as Norlun Troughs, Nor’easters, Alberta Clippers, Upsloping Events and more.

Sign Up Now!

This course is geared to avalanche professionals, guides, and mountain rescuers.

Registration is limited in number with scholarship seats available for $40 awarded by nomination to 2 members of each local rescue team. More seats will be available to people unaffiliated with local teams for $80.

 

The class is 16 hours long and spread over the following dates:

  • Wednesday, February 21, 5-9pm at IME
  • Friday, February 23, 5:30-9pm at the MWObs Weather Discovery Center (WDC)
  • Wednesday March 7, 5-9pm at the MWObs WDC
  • Wednesday March 21, 5-9pm at the MWObs WDC

 

Proceeds of the course will benefit the White Mountain Avalanche Education Foundation.

 

Avalanche Advisory for Sunday, February 18, 2018

Huntington and Tuckerman Ravines have CONSIDERABLE avalanche danger. All forecast areas have Considerable avalanche danger. Large avalanches in specific areas and small avalanches in many areas are possible. Dangerous avalanche conditions. Careful snowpack evaluation, cautious route finding, and conservative decision making are essential.

AVALANCHE PROBLEM: Wind Slabs that will continue to develop through the day are our primary avalanche problem. Avalanche danger will increase through this afternoon as wind builds our several inches of new snow into much thicker slabs. Increasing wind speeds mean than snow deposited will be generally more dense over less dense snow and therefore be increasingly sensitive to a trigger. Natural avalanches will be possible and human triggered avalanches will be likely. Dry loose sluffs which could knock you off your feet, initiated naturally or by a human, should also be on your radar in our steep terrain. We still have relatively thin snow coverage in much of our terrain, particularly Huntington Ravine. This means that many hazards in the runout of our avalanche paths elevate the consequences of even a small avalanche. Consider the rocks, vegetation, and terrain traps which may be below you if you choose to travel in avalanche terrain today. Also remember that though avalanches typically occur on slopes steeper than 30 degrees, they can run well into flat areas like the floor of Tuckerman Ravine.

 WEATHER: New snow overnight is currently tapering off as wind increases and shifts NW. Mixed snowfall totals and accumulation on the ground lead us to approximate 3” of new snow in our terrain. This morning could bring another trace to 1” with no precipitation expected later today. New snow density at Hermit Lake is 6.9%. SW shifting to W summit wind of around 40 mph accompanied the bulk of precipitation. Wind has shifted NW this morning and should increase with a peak in the 50-60 mph range early this afternoon. Temperature on the summit will hover around 10F. Tomorrow should bring warmer temperatures ahead of a weather system arriving late in the day that could bring mixed precipitation.

SNOWPACK: The wind slabs that are currently forming lie on a mixed surface of icy refrozen snow and areas of wind slab formed early yesterday. Snow deposited Friday night into yesterday morning formed many pockets of wind slab that were largest in areas like the Sluice and Lip of Tuckerman Ravine and smoothed the icy snow surface with a thin layer of snow in areas with lesser slab development. This means that today’s newly forming slabs will have a smooth bed surface and avalanches in this slab could entrain additional snow and become larger. A series of melt/freeze cycles last week limit stability concerns to snow which has fallen in the past two days. Expect varied slab characteristics in this new snow which is loading on shifting and increasing wind with potential for touchy slabs in much of our 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 Harvard Cabin.
• Posted 8:15 a.m., Sunday, February 18, 2018. A new advisory will be issued tomorrow.

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

2018-2-18

Avalanche Advisory for Saturday, February 17, 2018

Huntington Ravine has MODERATE and LOW avalanche danger. Central and Pinnacle Gullies have Moderate avalanche danger. Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully to identify features of concern. All other forecast areas have Low avalanche danger. Watch for unstable snow on isolated terrain features.

Tuckerman Ravine has MODERATE and LOW avalanche danger. Sluice, Lip, Center Bowl, and Chute have Moderate avalanche danger. Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully to identify features of concern.  All other forecast areas have Low avalanche danger. Watch for unstable snow on isolated terrain features.

AVALANCHE PROBLEM: New snow in the past 24 hours, combined with strong winds, created wind slabs on our icy snowpack. These wind slabs are on the smaller side but are likely poorly bonded to snow beneath making human-triggered avalanches possible in wind loaded areas. Areas of wind slab will be easy to identify as they will stand out in contrast to the gray, old refrozen snow that still exists. Smooth pillows of new snow should be evaluated carefully for signs of instability or avoided all together. The new snow helped refill some of the forecast areas but “dust on crust” conditions will be likely in all but a few sheltered areas like Sluice and Lip in Tuckerman Ravine and Central and Pinnacle Gullies in Huntington. Be on the lookout for propagating cracks or hollow sounding pockets of wind slab in low rated areas as well where the icy crust can provide safer travel but a challenging self-arrest surface if you fall.   

WEATHER: The summit recorded snow with 0.5” of SWE since about 3pm yesterday afternoon. It became pretty clear while riding up the Tucks trail this morning that this snowfall was elevation dependent due to the meager inch or so on the ground at Pinkham Notch that grew in depth a bit at mid-elevations. The Hermit Lake snowplot recorded 4 cm of 11.8% new snow on the board. Winds during the snowfall from the WNW ramped up to the 60-70 mph range and moved snow into increasingly dense wind slabs. The snowfall trailed off as winds diminished. Temperatures dropped yesterday from a high of 30F on the summit to -9F early this morning. Winds are currently light under bluebird skies. Winds will diminish further this afternoon to the 20-35 mph range as temperatures rise to 11F under increasingly cloudy skies.

SNOWPACK: Deeper instabilities in our snowpack were more or less erased with the two warm spells that occurred this past week. Cold temperatures returned overnight and have once again locked up percolating water and sintered old snow. In our forecast areas, you will find the refrozen snow will easily support your weight except in areas around bushes or boulders. If you look hard enough, you may be able to find some early faceting going on around the crust but it is unlikely to be a weaker layer than the new and old snow interface or the soft early storm snow.  

If you are in town for the weekend and looking for something to do, join us at International Mountain Equipment at 5 pm for Ryan’s talk on snow stability tests and how to use them. With luck, we will live stream this on Facebook Live.

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 Harvard Cabin.
• Posted 8:01 a.m., Saturday, February 17, 2018. A new advisory will be issued tomorrow.

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

2018-2-17