Avalanche Advisory for Saturday, March 31, 2018

Huntington and Tuckerman Ravine have LOW avalanche danger today. All forecast areas have Low avalanche danger. Generally safe avalanche conditions exist.

AVALANCHE PROBLEM: Due to the melt-freeze cycle the mountain experienced over the past 48 hours, avalanche concerns have subsided for the day. A big drop in temperature following ¾” of rain has locked the surface of the snowpack and left avalanche terrain with a smooth, icy surface. Long, sliding falls will be the main concern today for skiers and climbers and will necessitate the skillful use of crampons and ice axes. In addition to this, other spring hazards are starting to appear, though weather today should prevent further development of undermined snow and keep most rock and ice in place rather than cascading down.  Climbers should be wary of ice dams as the cold snap will have trapped running water under a coating of ice that is waiting for pressure release in the form of a tool or screw placement. The Little Headwall is now open water and not recommended as an exit for those looking to ski out of Tuckerman Ravine.

WEATHER: On Thursday morning, the summit of Mount Washington recorded above freezing temperatures that stayed above 32F for 30 hours. During this time period, the summit also recorded 0.75” of rain. At noon on Friday, temperatures began a downward trend that bottomed out at a current 3F on the summit and 14F at Hermit Lake. As today progresses, a ridge of high pressure over the region will keep skies clear until late in the day when upper level moisture will bring clouds in the evening. Temperature will be colder than it looks today with highs on the summit maybe reaching 20F by early afternoon. Wind is currently out of the NW at 65mph and will shift to the SW as high pressure moves out of the region late in the day. Wind speeds should drop to the 30-45mph midday and then increase again when the wind shifts to the SW.

SNOWPACK: As expected, our snowpack took a hit from yesterday’s rain. There is significantly less snow in the tops of gullies than earlier in the week. That being said, due to the porosity of the snow that arrived in early March, the snowpack was able to accept the rain well and we saw no drastic changes beyond the Little Headwall opening up. Today certainly has the appearance of spring, though those stepping out of their cars in the Pinkham parking lot at 7am might beg to differ. During our morning forecasters meeting, we discussed whether we thought the snow would soften today. Despite a combined give or take 45 years of experience, we struggled to say yes or no. If you are looking for spring skiing today, it might happen given the clear skies. That being said, cold temperatures and forecast wind speeds may prevent even south-facing slopes like Right Gully and Lobster Claw from softening. Wise skiers will carry crampons and an ice axe today and be prepared to down climb or wait and pray for the snow to soften.

The Sherburne still has full snow coverage from top to bottom, though ice is starting to appear in the usual places.

Tonight is the last night of operation for the Harvard Cabin, Starting tomorrow, the only place to camp in the Cutler River Drainage will be at Hermit Lake Shelters.

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  8:00 a.m., Saturday, March 31, 2018. A new advisory will be issued tomorrow.

Helon Hoffer, Snow Ranger
USDA Forest Service
White Mountain National Forest
(603) 466-2713 TTY (603) 466-2858

2018-03-31

Avalanche Advisory for Friday, March, 30, 2018

Huntington and Tuckerman Ravines have MODERATE avalanche danger. All forecast areas have Moderate avalanche danger. Heightened avalanche conditions on specific terrain features.

AVALANCHE PROBLEM: Rain on cold, dry layers of snow raises our avalanche danger today. Warm temperatures and rain overnight will continue into the early afternoon hours today, adding strain to the weak layers that exist in the snowpack. There is a good chance that no natural avalanches will occur today, but any avalanche, natural or human-triggered, could be large and destructive. If, for some reason, you venture out into avalanche terrain in the cold rain today, keep this low probability but high consequence avalanche problem in mind. Temperatures will fall to the freezing level this afternoon and continue to drop through the night bringing improved stability to the snowpack. It will also create a hard, icy surface layer that sunshine and cool temperatures tomorrow may have a hard time breaking down.

Spring hazards are becoming prominent and should be considered in your terrain decisions. Long sliding falls on the hard, icy snow will be possible. Given the rain and refreeze, don’t count on the firm Styrofoam snow to be around tomorrow. Ice climbers should be aware of potential for ice dams in many climbs which can rupture with the placement of a tool, crampon, or screw. Above freezing temperatures will result in water flowing beneath ice which will become brittle in places when temperatures drop tonight. Undermined snow in stream beds will make exiting the Bowl challenging.

WEATHER: About a 0.4” (9.7mm) of rain fell overnight at Hermit Lake with more on the way today. The temperature is currently 39F on the summit and will slowly fall through the day, ultimately bottoming out at 8F on the summit at sunup tomorrow. West wind today will diminish a bit to 40-45 mph this afternoon but slowly ramp up and blow 65-70 mph tomorrow morning. Summit wind will diminish a bit tomorrow afternoon to 55-60 mph. Sunny skies are on tap and will likely seem appealing for a spring ski day but be prepared for borderline snow conditions which may struggle to soften even on sunny aspects.

SNOWPACK: Field time on the summit yesterday was a reminder of how important the direct sun and above freezing temperatures are to soften the snow surface. The more east facing snowfields were rock hard at 12 noon, despite sunlight filtered only by very thin, high clouds and temperatures at 34F. Wind from the west near 40 mph and indirect sunshine were enough to keep the snow from softening. Lower down the mountain, conditions improved on slopes facing directly into the sun but temperatures were quite warm there early on. Solar gain will be critical tomorrow. If you are choosing to come up on Saturday, remind yourself that the pressure that comes from a crowd of people is hard to withstand. Long-sliding falls often result in no injury whatsoever but have, on many occasions, resulted in life altering injuries and death. Look for sun softened snow, not the boot ladder with the most people.

Check our Instagram page, linked on our website, for conditions photos and additional updates. You don’t need an account to view our posts!

The Harvard Cabin will be open tonight and Saturday night and then close for the season.

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  8:00 a.m., Friday, March 30, 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) 466-2858

2018-03-30

 

Avalanche Advisory for Thursday, March 29, 2018

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

AVALANCHE PROBLEM: Temperatures will rise well above freezing today. So far, heating has been limited to the sunniest slopes and even then, wind and cool temperatures has limited heating to the surface. Today’s weather and snowpack trend is similar to the day a few years ago when a very large human triggered avalanche occurred on the summit cone. The warm temperatures that melt bonds between grains in the snowpack and create great skiing and riding conditions also melt bonds deeper in the snowpack. The first strong warming trend tests the strength of the snowpack, and in our case today, creates a low probability, high consequence avalanche problem. Natural and human-triggered avalanches are unlikely in most of our terrain but the threat of a large, hard slab makes it advisable to ski or ride a slope one at a time and to continue to carry your avalanche rescue gear. Large convexities or thin spots would be the most likely locations to trigger this type of avalanche. Wet loose avalanches could also occur in areas with strong solar gain or in the limited areas where soft snow remains. Low avalanche danger does not mean no avalanche danger!

WEATHER: A strong inversion this morning has valley locations slightly cooler than the summit which has already reached 30F. Tuesday night brought a trace amount of mixed precipitation to the mountain. Today looks clear and fairly calm though SW flow will bring clouds and eventually rain later this afternoon and evening. It looks as if these clouds won’t lower to become summit fog until nighttime though high clouds already developing this morning may reduce solar gain a bit this afternoon as they thicken. Temperatures should reach to the mid or high 30’s with 20-35 mph SW wind in the afternoon. Almost an inch of rain is forecast overnight and will further test our snowpack into tomorrow. Percolating rain in the snowpack will likely raise our avalanche concerns further tomorrow. 

SNOWPACK: The hard, icy melt-freeze crust that exists deep in the snowpack, beneath the firm wind slabs which developed March 17th, is one of the layers that will be a player in avalanche activity that occurs over the next couple of days. Rapid warming is one of the classic red flags signaling avalanche danger, along with heavy precipitation of any variety. The next 48 hours will bring changes to the snowpack which will ultimately reduce our avalanche concerns to the surface. Until then, we will continue to have the potential for a larger hard slab avalanche.

The Sherburne Ski Trail has good coverage top to bottom and should soften through the day. The usual scoured areas may start to reveal some rocks.

Check our Instagram page, linked on our website, for conditions photos and additional updates. You don’t need an account to view our posts!

The Harvard Cabin will be open all nights this week.

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  7:45 a.m., Thursday, March 29, 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) 466-2858

2018-03-29

Avalanche Advisory for Wednesday, March 28, 2018

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

 AVALANCHE PROBLEM: Snow on sun exposed slopes yesterday saw at least some degree of softening, which was followed by a quick refreeze in the afternoon. Areas seeing less direct sun continued to hold dry snow. Avalanche concerns are limited to small loose dry sluffs in this dry snow and loose wet sluffs when the refrozen snow warms again. The snowpack is exhibiting good stability and the current wintry mix of precipitation will not significantly change this. That said, we’re still far from a spring snowpack and it remains wise to travel one at a time in avalanche terrain while carrying a beacon, probe, and shovel.

 Spring hazards are becoming prominent and should be considered in your terrain decisions. Long sliding falls on the hard snow, which essentially all steep terrain holds, is a key concern today. If you brave the weather to travel in the alpine, crampons and an ice axe will be crucial equipment. Ice climbers should be aware of potential for ice dams in many climbs which can rupture with the placement of a tool, crampon, or screw. Recent above freezing temperatures has resulted in water flowing beneath ice and can create this hazard.

 WEATHER: A sunny and above freezing day yesterday gave way to increasing clouds which ultimately brought a wintry mix of precipitation to the mountain. Under an inch of mixed precipitation fell overnight and precipitation has tapered off this morning. Summit temperatures will hover around freezing as NW wind blows around 20 mph. Cloud cover should decrease to partly cloudy conditions by late today before increasing again by late tomorrow, bringing another round of precipitation that is currently forecast to fall as rain on the higher summits.

SNOWPACK: The nor’easters of two weeks ago ultimately built a firm upper snowpack which has exhibited good stability. Warming over the last two days did not penetrate deeply into this firm snow, though did allow softening yesterday to allow 4-6” of boot penetration on areas seeing greatest solar heating. These areas refroze quickly. Terrain which remained shaded or saw less direct sun continued to hold dry, cold, and firm snow. The mix of snow and sleet which fell overnight totaled less than a half inch at Hermit Lake. It has likely created additional variability in our snow surface but is not posing a stability concern. Avalanches are unlikely in the current conditions but the limited freeze-thaw action in recent weeks means that we still have a winter-like snowpack structure. The transition to an isothermal spring snowpack will likely occur in the coming weeks and is a time to begin planning for a variety of mountain hazards.

Check our Instagram page, linked on our website, for conditions photos and additional updates. You don’t need an account to view our posts!

The Harvard Cabin will be open all nights this week.

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  8:00 a.m., Wednesday, March 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) 466-2858

2018-03-28

Avalanche Advisory for Tuesday, March 27, 2018

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

 AVALANCHE PROBLEM: A significant warm-up today will make loose wet sluffs the primary avalanche problem on sun exposed aspects. Loose dry sluffs are still possible on steep and shady aspects. We expect these small avalanches which could easily knock you off your feet to occur primarily in the few inches of snow which fell late Saturday and into Sunday. The small and isolated pockets of soft and thicker wind slab which formed from that recent snow could begin to act as a wet slab on south facing slopes and should be on your radar in all terrain. The older, widespread, and hard wind slab that is thinly covered in many areas by the newer snow has been unreactive to human and natural triggers and this trend will likely continue. That said, a significant warming like our sun-exposed slopes will experience today can awaken previously unreactive layers at or near the surface. It’s again a reason that “Low” does not mean “No” avalanche danger, and that travelling one at a time, with your beacon, probe, and shovel, is advisable.

 Also be aware that while the sun will soften some aspects, others will remain hard, and sun softened snow can quickly refreeze with the return of shade. Crampons, ice axe, your ability to use them, and wise terrain choice are all necessary tools to prevent a high consequence long sliding fall. Sun will also warm ice today, making icefall a key overhead hazard to consider and manage.

 WEATHER: Current summit temperature is approaching 20F, already nearing yesterday’s high of 24F and forecast to exceed the freezing mark today. Yesterday’s high of 41F at Hermit Lake will almost certainly be exceeded. Yesterday was warm and spring-like, but today will be our first truly warm weather in several weeks. Southeasterly summit winds will remain under 20 mph until a warm front arriving late today brings slightly higher wind speeds and increasing cloud cover. Precipitation of a wintry mix is forecast to begin tonight but only fall in light amounts. Snow and sleet are forecast to total a trace to 2” by the end of tomorrow, with freezing rain or plain rain possible as well.

SNOWPACK: The few inches of snow which fell this weekend lies on a hard and stubborn two week old wind slab. This older snow also exists at the surface in many places. Today’s weather will be the first significant warming event on our current snowpack structure. Strong springtime solar energy and above freezing temperatures in the ravines will begin to transform our dry upper snowpack, though shady aspects may see minimal affects. Sun exposed aspects, which experienced some warming yesterday and a refreeze overnight, present the possibility for loose wet sluffs in the newer and softer snow today. The effect of warming on a previously unreactive hard slab, which is currently dominant in our upper snowpack, is notoriously tricky to forecast. We don’t expect avalanches from this layer, but it’s worth travelling as if one could occur. Skiers and snowboarders will likely find surface snow become more forgiving today on sunny aspects, though nearly all terrain holds snow allowing decent edge grip and excellent conditions for crampon travel.

The Harvard Cabin will be open all nights this week.

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  7:50 a.m., Tuesday, March 26, 2018. A new advisory will be issued tomorrow.

Ryan Matz, Snow Ranger
USDA Forest Service
White Mountain National Forest
(603) 466-2713 TTY (603) 466-2858

2018-03-27

Avalanche Advisory for Monday, March 26, 2018

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

 AVALANCHE PROBLEM: Limited wind transport of the several inches of snow which fell in the past 48 hours make loose dry sluffs our primary avalanche problem. Loose snow avalanches won’t bury you today but could knock you off your feet and are possible on most steep slopes. The new snow is distributed fairly evenly across our terrain, though a few areas saw wind scouring and the possibility for small, isolated pockets of wind slab does exist. A firm and generally smooth surface of older snow exists beneath the thin new snow. Conditions are generally edge-able and good for crampon and ice axe travel, but don’t expect to arrest a fall with any ease. A long sliding fall which could be caused by a loose dry sluff or just a stumble is likely your primary hazard to manage today.

 WEATHER: Skies have trended toward the current clear conditions as northerly wind has remained below 30 mph, with the exception of a few gusts. Currently, wind on the summit is NE at 20 mph with a temperature of 6F. High pressure is allowing this weather to hold through today and tonight, with temperatures warming by a few degrees and wind remaining mild by Mount Washington standards. These generally pleasant conditions should persist into tomorrow morning before clouds, rising temperatures, and increasing winds arrive with a warm front later in the day. Precipitation forecast to begin late tomorrow or early Wednesday is currently forecast to be a wintry mix.

SNOWPACK: The significant snow which fell nearly two weeks ago now was heavily wind transported. It ultimately became hard, dry, and stubborn to unreactive slabs which are widespread in our terrain. Three inches of snow has fallen since Saturday and has been relatively unaffected by wind, with the exception being isolated areas of scouring and even more isolated pockets of wind slab. It’s not quite dust on crust conditions, with the old hard snow providing decent turning conditions and great crampon purchase, but certainly consider sliding falls when choosing terrain today. Though it’s nearly April and spring-like weather may be coming later this week, expect winter snow on this crisp but blue sky day.

The Harvard Cabin will be open all nights this week.

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  8:00 a.m., Monday, March 26, 2018. A new advisory will be issued tomorrow.

Ryan Matz, Snow Ranger
USDA Forest Service
White Mountain National Forest
(603) 466-2713 TTY (603) 466-2858

2018-03-26

Avalanche Advisory for Sunday, March 25, 2018

Huntington Ravine will have MODERATE and LOW avalanche danger today. Central Gully will have Moderate avalanche danger. Heightened avalanche conditions exist on specific terrain features; identify those of concern. All other forecast areas in Huntington have Low avalanche danger. Watch for unstable snow on isolated terrain features

Tuckerman Ravine will have MODERATE and LOW avalanche danger today. Sluice, Lip, and Center Bowl will have Moderate avalanche danger. All other forecast areas will have Low avalanche danger. Watch for unstable snow on isolated terrain features.

AVALANCHE PROBLEM: Snow that arrived overnight has the potential to form wind slab and dry-loose avalanches. Another shot of snow this morning will exacerbate this problem. While wind speeds should remain mild by our standards, the recorded snow has a very light density, making wind transport possible on low wind speed. Wind speeds should increase slightly this morning to above 40mph. This has the potential to load snow into the northern gullies in both ravines as well as cross-load Moderate rated terrain. With the combination of snow density and wind speeds, expect wind slab to be touchy to a human trigger, particularly with the firm bed surface it will reside on. While northern gullies in Huntington are more in the direct lee of today’s wind, a smaller fetch and confined, steep terrain will make dry-loose sluffing more of a an issue. If an avalanche occurs, it is likely to be small, but potentially enough to swipe your feet out from underneath you and lead to a long, sliding fall. As the bed surface in all avalanche terrain is firm, arresting a fall today will be difficult.

WEATHER: Afternoon and overnight snow showers capped off a largely bluebird day yesterday. As of this morning, the Summit recorded 1.1” of snow while Hermit Lake recorded 2.8” of 4% snow. Around dusk last night, wind speeds dropped to calm and shifted from the NW to the NE, before slowly increasing to a current speed of 35mph. Another inch of snow may arrive this morning while wind should shift to the N later in the day. Wind speed may increase slightly this morning before decreasing to the 20-35mph range for the afternoon.

SNOWPACK: March began with a bang in terms of snowfall and was followed by a period of 100mph wind. This left areas of firm wind slab with some areas seeing scouring. The firm wind slab has proven to be edgeable and unreactive to human or natural triggers. Areas of softer snow do exist in Huntington, but it still firm enough to make stopping a fall very difficult. Snow prior to yesterday afternoon will act widespread as a bed surface and should not contribute any volume of snow to an avalanche should one occur. New snow will likely cover variability in the old snow, hiding transitions in textures and possibly leading to mis-steps while skiing or climbing that could lead to a fall.

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  8:00a.m., Sunday, March 25, 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

2018-03-25

Avalanche Advisory for Saturday, March 24, 2018

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

AVALANCHE PROBLEM: High temperatures in the low teen’s F, very firm snow surfaces and summit fog may have skiers dreaming about days of elevated avalanche danger today. Though climbers will appreciate the ease of climbing on the firm surface, skiers will be dealing with hard, fast conditions with no chance for softening snow. Light snow showers on light NW winds early this morning have created the illusion of fresh snow but don’t be fooled by the dust on crust effect. More snow showers today may create pockets of wind slab that will serve only to exacerbate the long sliding fall concern. For these reasons, expect low avalanche danger in all forecast areas due to new wind slabs this afternoon. Ice climbers should be aware that a climber fell up to their waist in the icy water behind an ice dam in Odell Gully yesterday. Expect the potential for an ice dam rupture to exist for a while on all ice climbs as spring continues and temperatures swing around the freezing point. Large chunks of ice are also beginning to appear on the floor of both Ravines.

WEATHER: Two inches of new snow may fall late this afternoon as a cold front pushes into the area today. Currently, the summit is in and out of the clouds at 10F with wind from the N at 11 mph. High clouds will thicken and lower through the day, bringing summit fog and challenging visibility, especially if snow showers develop later in the afternoon. All in all, today will play out like a mild winter day with the temperature struggling to reach above its current position. Relatively light NW winds should make travel above treeline more comfortable than usual.   

SNOWPACK: It’s been six days since any measureable precipitation fell on the summit besides the trace that fell overnight. Sixty-six inches of snow has fallen on the summit so far this month, accompanied by colder than normal temperatures, allowing our snowpack to bounce back a bit from the deficit we entered in January and February. There is currently 168cm of snow at the stake at the Hermit Lake snowplot, showing 5 cm of settlement since Thursday of what has remained a cold, dry snowpack at upper elevations. The 30” snowfall 10 days ago and 100mph+ westerly wind and avalanche cycle that followed, filled out most east and south facing slopes and runouts in an impressive way. For now, Ravines are in pretty good shape, though gullies on the right sides have top to bottom, but limited snow coverage. Snow surfaces most everywhere above treeline are very hard, but pockets of softer snow, some of it covered by a thick and grabby wind skin, exist in sheltered locations like the edges of gullies. This variability will keep you on your toes when skiing or climbing, especially considering the hard surface in most fall lines.

The Sherburne Ski Trail improved a lot after last week’s snowfall. Great coverage exists, though a bit of scouring may have exposed a rock or two in the usual wind hammered sections.

Be sure to check out our Instagram posts (@mwacenter) for up to date photos and videos. You don’t need an account to view them on your computer!

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 7:50 a.m., Saturday, March 24, 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

2018-03-24

Photo Update on March 23, 2018

 

Tuckerman Ravine. The hard wind slab is manageable on skis but ice axe and crampons are reassuring even on lower angle parts of the terrain.

The avalanche debris in lower snowfields and the bottom of Hillman’s is navigable and slowly filling in.

Huntington Ravine. The hard windslab is providing a excellent surface for cramponing. Ice fall is starting to show up in the bottom and will continue to be a problem as temperatures increase.

Pinnacle & Odell

Yale & Damnation

Multiple large chunks were observed in the floor this morning. Remember overhead hazards while making travel choices as the temperatures warm up.

 

Avalanche Advisory for Friday, March 23, 2018

 

Huntington and Tuckerman Ravine have LOW avalanche danger today. Generally safe avalanche conditions exist. Watch for unstable snow on isolated terrain features.

AVALANCHE PROBLEM: Wind slab is the avalanche problem today. It is unlikely that a human could trigger the current wind slab in our terrain due to its firm and supportive nature. As the slab itself has a high degree of tensile strength, an avalanche would be large, giving travelers in avalanche terrain a classic low probability, high consequence situation. Small areas of softer slab exist that are providing the isolated pockets of less stable snow. The surface of our snowpack is largely smooth, providing quality skiing, but also the ideal surface for a long, sliding fall. Losing a ski edge or catching a crampon point in steep terrain today will likely have dire consequences. With the possibility of 1” of snow today, dry loose sluffing in extreme terrain should be on your radar as wind speeds are forecast to be on the low side.

WEATHER: The fourth Nor’easter of March was less impressive than the others, bringing overcast skies and mild temperatures. We saw no new snow yesterday (or any of the previous four days), recorded a high temperature of 19F and a low of 9F on the Summit, and saw NE wind shift to the NW and stay in the 30-50mph range. Today will be somewhat similar, though summit fog should move in this afternoon. Wind will drift between N and NW and stay in the 25-40mph with periods of lower speeds. Up to an inch of snow may materialize today, though this should be hold off until later in the day if at all.

SNOWPACK: Significant snowfall in early-March followed by recent strong wind has left widespread, firm wind slab in most of avalanche terrain. This wind slab is supportive and is providing excellent climbing and good skiing provided you bring crampons and stay on your edges. Softer pockets of snow exist under terrain features and near the edges of gullies, particularly in the trees. Off trail travel that is not in a gully may require serious post-holing.

The Harvard Cabin is open this weekend.

Please Remember:
• Safe travel in avalanche terrain requires training and experience. This advisory is just one tool to help you make your own decisions in avalanche terrain. You control your own risk by choosing where, when, and how you travel.
• Anticipate a changing avalanche danger when actual weather differs from the higher summits forecast. For more information contact the Forest Service Snow Rangers, the AMC at the Pinkham Notch Visitor Center, or the caretakers at Hermit Lake Shelters or Harvard Cabin.
• Posted 7:50 a.m., Friday, March 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

2018-03-23

Avalanche Advisory for Thursday, March 22, 2018

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

AVALANCHE PROBLEM: A low pressure system passing to our south and east may generate 2” of snow today on the mountain. This snow will fall on N and NE winds and may build and cross-load small wind slabs in sheltered locations, particularly northern gullies in Huntington and the right side of Tuckerman Ravine. Any wind slabs that build will be on a very firm, and in most places, smooth snowpack. The hard snow surface will increase the likelihood of triggering a small wind slab and raise the consequences if you were to be surprised or swept off of your feet. If you are playing in steep terrain, an ice axe and crampons will make you feel a lot more secure due to the hard and just barely edge-able snow. Though wind slab may be the primary avalanche problem, a long sliding fall is a close second on the list of hazards.  

WEATHER: It is 20F at Hermit Lake this morning and 16F on the summit with relatively light easterly winds in the 40mph range. Winds will increase to the 50-70mph range as they wrap around to the north through the day. Expect temperatures in the high-teens F on the summit with a chance of snowfall bringing up to 2”, though likely less. Summit fog may obscure visibility at times. Certainly not a bluebird day on tap for this early spring day, but not a bad day to be out and about.

SNOWPACK: It’s been four days since any measureable precipitation fell on the summit, though cool temperatures between 0 and 20F have preserved this new snow well. Sixty-five inches of snow has fallen so far this month on the summit accompanied by colder than normal temperatures, allowing our snowpack to bounce back a bit from the deficit we entered in January and February. There is currently 173cm of snow at the stake at the Hermit Lake snowplot. With a warm and dry pattern in the long-range forecast, who knows how long the snowpack will last. The 30” snowfall last week and the howling 100mph+ westerly wind that followed filled out the slopes and runouts in an impressive way. For now, Tuckerman Ravine is in pretty good shape, though gullies on the right side still have limited coverage despite having enough bed surface to generate avalanche activity there during the last avalanche cycle. Snow surfaces are predominately hard, but pockets of softer snow, some of it covered by a thick and grabby wind skin, exists in sheltered locations like the edges of gullies. This variability will keep you on your toes when skiing or climbing, especially considering the hard surface in most fall lines.

The Sherburne Ski Trail benefited greatly from last week’s snowfall. Great coverage exists, though a bit of scouring may have exposed a rock or two in the usual wind hammered sections.

Be sure to check out our Instagram posts (@mwacenter) for up to date photos and videos. You don’t even need an account to view them online if you are trying to avoid social media!

The Harvard Cabin will be open all nights this week.

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 8:10 a.m., Thursday, March 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

2018-03-22

Avalanche Advisory for Wednesday, March 21, 2018

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

 AVALANCHE PROBLEM: The widespread and firm wind slabs formed late last week are becoming generally unreactive as they gain stability. Isolated and softer pockets may still be touchy to a human trigger. Also consider that solar warming, which could occur today before cloud cover increases, has potential to decrease stability of existing slabs. Low avalanche danger means that both natural and human triggered avalanches are unlikely, but that doesn’t rule out avalanches as a potential concern for your mountain travel. Continue to pay attention to the snow you’re travelling on and plan to travel, looking for signs of instability to identify the isolated pockets that may remain touchy to a human trigger. Travelling one at a time in avalanche terrain is still wise with avalanches unlikely but not impossible.

 WEATHER: High cloud cover will increase through the day following yesterday’s clear skies and moderate summit winds. It’s currently nearly calm on the summit, with easterly wind speeds under 10 mph. This wind will increase through the day, ultimately shifting NE and exceeding 50 mph tonight. The high temperature on the summit should be near 20F. This unsettled weather is the result of yet another Nor’easter, though this system is forecast to largely miss the Presidential range. Snowfall which will begin late tonight and continue into tomorrow could total anywhere from 2-6” as wind eventually shifts N and gusts to around 80 mph.

SNOWPACK: Successive storms late last week built an upper snowpack of layered wind slabs on an old melt/freeze crust. These generally firm slabs are gaining stability and becoming unreactive, though isolated pockets that you could still trigger do exist. It’s worth considering that wind slab is a spatially variable avalanche problem by nature as you choose and move through terrain today. Our snow surface is a mix of smooth and wind textured firm wind slab with the scattered pockets of softer slab that pose a greater stability concern, and is providing enjoyable conditions for skiers and climbers alike. This morning looks to provide a continued nice weather window to enjoy the mountain before clouds and wind increase later today.

The Harvard Cabin will be open all nights this week.

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 8:00 a.m., Wednesday, March 21, 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

2018-03-21

Avalanche Advisory for Tuesday, March 20, 2018

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

 AVALANCHE PROBLEM: Wind slab which varies in size and character across the terrain remains our primary avalanche problem. Present in all forecast areas and largest in Moderate rated areas, these slabs should be stubborn to a human trigger but could result in a large avalanche. Cold temperatures which slow bonding between recently formed layers lead us to believe that human triggered avalanches are still possible today, though natural avalanches will be unlikely. Surface snow is fairly firm and supportable in many areas, but softer pockets can be found as well. This spatial variability necessitates careful evaluation of the avalanche problem on your specific route, and that travelling one at a time on and below all avalanche terrain remains appropriate. “Low” avalanche danger does not mean “no” avalanche danger!

 WEATHER: Yesterday’s 60-80 mph NW summit wind has finally begun to diminish. This should continue through the day, possibly to below 30 mph this afternoon. A high of 15F on the summit, compared to -3F yesterday, will combine with slackening winds and generally clear skies to make for a nice day in the mountains. Wind is forecast to shift through N to NE tonight and into tomorrow while increasing slightly. Cloud cover should increase through the day tomorrow, bringing a chance of minimal snowfall late Wednesday and into Thursday.

SNOWPACK: The repeated 100+ mph wind events at the tail end of last week’s storm cycle moved a great deal of snow and left little for our 50-80 mph winds to transport in the past few days. Combined with a widespread natural avalanche cycle, our alpine terrain holds much more snow than it did a week ago. This new snow is generally firm layers of wind slab, with some softer pockets both on and below the surface. These slabs are generally stubborn to a human trigger but are large and well connected in some areas, providing a low probability/high consequence kind of avalanche problem. Particularly cold temperatures which are finally easing today have slowed stabilization of these layers formed at the tail end of last week. Today’s warmer though still below freezing temperatures could result in a brief and minor decrease in stability before ultimately increasing strength of bonds in our upper snowpack. Don’t let your guard down, continue to respect avalanche terrain, and enjoy the milder weather and generally good skiing and climbing conditions.

The Harvard Cabin will be open all nights this week.

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 8:00 a.m., Tuesday, March 19, 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

2018-03-20

Avalanche Advisory for Monday, March 19, 2018

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

 AVALANCHE PROBLEM: Wind slab remains our primary avalanche problem today. Generally firm and relatively stubborn to a human trigger, these recently formed surface layers are of most concern in Moderate rated areas where they are particularly large, potentially well-connected, and smooth on the surface. These surface slabs are layered over others formed in the past week, and while we’re not overly concerned with an avalanche initiating deep in the snowpack, it’s worth considering that an avalanche today could ultimately entrain a great deal of snow. It’s a low probability/ high consequence kind of day, with your likelihood of triggering an avalanche not exceeding “possible”. Travelling one at a time through and below avalanche terrain, from safe zone to safe zone, remains a wise and relevant practice on days like today.

 WEATHER: Today is forecast to be a near repeat of yesterday, as high pressure holds a cold air mass over our region. High temperatures on the summit should mimic the -3F recorded yesterday as wind remains NW in the 60-80 mph range until possibly diminishing a little tonight. The current summit fog should give way to clear skies. Tomorrow looks to be a more pleasant day, with temperatures 10 degrees warmer and NW wind decreasing through the day. Increasing high clouds are also forecast tomorrow but we shouldn’t see any precipitation.

SNOWPACK: Cold temperatures which slow stabilization and minimal wind transport in the past 24 hours mean that our snowpack remains much as it was yesterday. The multiple bouts of 100+ mph summit wind since last week’s series of Nor’easters has created largely firm snow conditions. These wind speeds create a great deal of spatial variability in our snowpack, with new slabs of great thickness in some areas while fairly thin in others. Character of these new layers varies accordingly, though we don’t expect sensitivity to a trigger to push beyond “stubborn” in these generally hard slabs. The exception would be small and isolated pockets of softer snow which may remain touchy. Yesterday was the first day of good visibility following our successive storms, and it revealed evidence of widespread mid-storm avalanche activity. Gullies that did not produce an avalanche, if any, were the exception rather than the rule. Of particular note are significant broken trees and avalanche debris just a few feet looker’s right of Connection Cache in Tuckerman Ravine. We don’t believe an avalanche has run to this area in recent years, and it’s an excellent reminder that a large avalanche can threaten flat terrain well below it.

The Harvard Cabin will be open all nights this week.

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 8:00 a.m., Monday, March 19, 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

2018-03-19

Human-triggered avalanches, Hillman’s Highway & Gulf of Slides, 2018-3-10

On Saturday, March 10, 2018, two separate avalanche incidents were reported. During the previous 2 days, 14.5″ of snow was deposited at Hermit Lake from a nor’easter and the upslope snowfall that followed. This storm was accompanied by moderate winds that rose to the 60’s mph the afternoon before. Saturday’s advisory called for 4.5″ more snow with increasing wind shifting slightly to the NW. Avalanche danger was rated Considerable in Hillman’s Highway, along with Left Gully and the Headwall forecast zones.

Around mid-day, a party of three talked with a snow ranger on duty who advised that low visibility and continued wind loading made their plan to travel into Hillman’s Highway unwise. The party hiked to Hillman’s and entered the 75′ wide couloir onto a 15-20 degree section of the otherwise steeper runout. Soon after the party returned to the courtyard and reported that everything the snow ranger had cautioned against had played out. Two were struck by debris, knocked down, and carried downslope. Fortunately, much of the energy of the debris flow was absorbed by boulders and holes from a warm spell which reduced our snowpack substantially. When the threat of natural avalanches occurring is elevated, the risks are as well. The natural avalanche that occurred in Hillman’s Highway was much larger and would likely have been unsurvivable.

The same day a party of two skiers set a skin track near the middle gully in the Fingers area of Gulf of Slides, in sparse trees. As the terrain steepened, they began to boot along the left edge of the gully next to the trees. The snow was loose and dry with “no shearing and bonding felt okay”. The first skier had been to this area many times and stayed out of the gully as they made their way towards the rollover near the top. They had spread themselves out as they moved up the slope but paused as they reached the rollover because “something felt wrong”. In moments, the slab failed a “couple hundred feet above” the party and hit both skiers. The first skier was carried but, being on the edge of the gully, he escaped the main flow of debris while the other skier clung to a nearby bush. The skier that was carried turned his beacon to search and could not locate a signal of his partner, who was still above him. Shortly after the caught and carried skier texted for help on his cell phone, the pair made contact and eventually were able to call off the rescue response. The skier who held onto the bush lost his poles while the skier who was carried lost all his equipment though eventually recovered one ski.

Later conversations with the skiers in Gulf of Slides revealed a debate as to whether or not they triggered the slope. They considered it likely that they did not trigger the slope, but rather that it had avalanched naturally. From our perspective, the trigger is relatively unimportant in this instance. If the avalanche had not released while ascending, it is possible that they could have made it to the top and triggered the slope on the way down. In that case, much more of the slab could have been above them with more serious consequences likely. After some reflection, looking at weather data and reading the avalanche advisory, the triggering skier admitted that “overconfidence due to personal experience” in that particular area led him to ignore the obvious red flags that existed due to the snow and weather conditions that day. After the period of warm weather and ice crust which had dominated recent ski conditions, it seems likely that the scarcity heuristic was in play as well. The call of fresh powder is hard to ignore sometimes but it is important to remember that good luck can play a role in good outcomes like this one and luck is one thing no one can count on.