Avalanche Advisory for Sunday, February 12, 2017

This advisory expires at Midnight.

Huntington and Tuckerman Ravine have MODERATE avalanche danger today. All forecast areas have Moderate avalanche danger. Natural avalanches are unlikely and human-triggered avalanches are possible. Heightened avalanche conditions exist on specific terrain features. Evaluate snow and terrain carefully to identify features of concern. The only exception to this rating is the Little Headwall which has Low avalanche danger. Natural and human-triggered avalanches are unlikely there.

A backcountry avalanche watch is currently issued. A warning will likely go into effect tonight through midnight on Monday. Tomorrow, snow totals approaching 24” combined with strong winds will create widespread natural avalanche activity.

AVALANCHE PROBLEM: Loose-Dry avalanches will be the concern for the main part of the day today. As snow accumulates, the likelihood of these will increase. Areas of Wind Slab that formed on Saturday remain primarily on north and north-east facing aspects. If traveling in terrain today, be on the lookout for softer pockets that exist near terrain features. While these soft wind slabs were cracking underfoot yesterday but not propagating, a loose dry overloading this today could add enough weight to propagate a fracture. As darkness falls and the bulk of the storm arrives during the night, expect storm slab and wind slab to form, rapidly increasing avalanche danger.

WEATHER: High winds from the NW that topped the century mark on Friday have gradually decreased to a current 12mph from the south. Yesterday, just over 4” of light density snow fell on our terrain. Today, snow looks to pick up in intensity in the early afternoon. By dark today, we may see up to 6” of new snow with winds shifting to the SE and increasing to 50mph. No matter how you look at the models for the approaching storm, there is a lot of snow coming. By Tuesday morning, we should see around 20” with high winds moving even more snow in avalanche terrain.

SNOWPACK: Scoured 1” thick breakable crust along with pencil-hard wind slab is the predominant snow surface to start the day. In lee areas of SW winds, scattered, soft wind slab formed yesterday and is primarily in mid-elevations of our terrain. This new softer slab was up to two feet deep in places under the steepest terrain, but made of light-enough density snow that it would not prevent postholing into the crust beneath. As snow arrives today, sluff management will present problems, especially if the sluff entrains this soft slab. As winds increase at the end of the day and the intensity of snowfall increases, storm slab and wind slab will become widespread. Expect rapidly increasing avalanche danger around dark this evening.

Please Remember:

  • Safe travel in avalanche terrain requires training and experience. This advisory is just one tool to help you make your own decisions in avalanche terrain. You control your own risk by choosing where, when, and how you travel.
  • Anticipate a changing avalanche danger when actual weather differs from the higher summits forecast.
  • For more information contact the Forest Service Snow Rangers, the AMC at the Pinkham Notch Visitor Center, or the caretakers at Hermit Lake Shelters or the Harvard Cabin.
  • Posted  8:25 a.m., Sunday, February 12, 2017. A new advisory will be issued tomorrow.

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

2017-02-12

Avalanche Advisory for Saturday, February 11, 2017

This advisory expires at Midnight.

Huntington and Tuckerman Ravine have MODERATE avalanche danger today. All forecast areas have Moderate avalanche danger. Natural avalanches are unlikely and human-triggered avalanches are possible. Heightened avalanche conditions exist on specific terrain features. Evaluate snow and terrain carefully to identify features of concern. The only exception to this rating is the Little Headwall which has Low avalanche danger. Natural and human-triggered avalanches are unlikely there.

AVALANCHE PROBLEM: Wind Slab and Loose Dry avalanches are possible in many areas today. Though on the smaller side, these avalanches could entrain enough snow to cause problems especially in steeper terrain or above terrain traps, boulders or trees. Small, loose dry natural avalanches could occur in a few areas like Pinnacle Gully and Chute. The primary concern however will be the wind slab avalanches that will likely be easy to trigger due to the low density snow coupled with light winds. Look for these wind slabs in upper start zones in the lee of features sheltered from southwest wind. Terrain with a north facing component is likely to have the greatest wind slab problem so be particularly heads up in Hillman’s Highway, Left Gully, South and Odell Gullies.

WEATHER: Currently in Pinkham Notch and Hermit Lake, the snowfall rate leads us to believe that we will reach the forecast 2-4” of snow early on today with 2-3” on the ground in Pinkham that fell mostly last night and this morning. Currently, wind speeds are blowing on the summit in the mid-30’s mph with some gusts near 50mph. NWS forecast models indicate that wind will continue from the southwest through daylight hours and only begin to shift to the northwest near dark. Wind will slack off through the day settling at the 20’s mph this afternoon. Temperatures on the summit are currently -3F but will rise to the teens.

SNOWPACK: Beneath this new snow you’ll find firm snow along with a dense ice crust in steep terrain. The crust will be breakable in sheltered or treed areas but will support your weight in our steep, open terrain. Areas of firm wind slab will be the primary bed surface in most of our mid-slope terrain. These older wind slabs developed on high wind speeds from the northwest, are stubborn and will likely be resistant to triggering due to the new snow load today.  Where the ice crust is closer to the surface and less insulated by the new wind slabs, you may find some faceting and weakening of the crust, though again it is not likely to be a player in avalanche activity today. These factors coupled with low density snow and light winds lead us to our moderate rating today. Remember that small avalanches can still hurt you so mind your runouts, approach steep, sluff deposited areas cautiously and use all your weather and snowpack assessment skills to confirm or deny the hazard level.

Please Remember:

  • Safe travel in avalanche terrain requires training and experience. This advisory is just one tool to help you make your own decisions in avalanche terrain. You control your own risk by choosing where, when, and how you travel.
  • Anticipate a changing avalanche danger when actual weather differs from the higher summits forecast.
  • For more information contact the Forest Service Snow Rangers, the AMC at the Pinkham Notch Visitor Center, or the caretakers at Hermit Lake Shelters or the Harvard Cabin.
  • Posted  8:00 a.m., Saturday, February 11, 2017. A new advisory will be issued tomorrow.

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

2017-02-11

Avalanche Advisory for Friday, February 10, 2017

This advisory expires at Midnight.

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

Tuckerman Ravine has MODERATE and LOW avalanche danger today. All forecast areas in Tuckerman Ravine have Moderate avalanche danger. Natural avalanches are unlikely and human-triggered avalanches are possible. The exceptions to this rating are Lower Snowfields and Little Headwall which have Low avalanche danger. Natural and human-triggered avalanches are unlikely.  Open water and ice remain exposed in the Little Headwall and the creek above. It is skiable but people have been occasionally punching through into water beneath.

AVALANCHE PROBLEM: Stubborn but potentially large wind slabs should be on your radar today if you brave the cold and wind to play in our terrain today. While the summit only recorded 1.5” of snow yesterday, we received closer to 5-6” at Hermit Lake. Our forecast area appears to have received something closer to that higher amount. Strong winds from the northwest built wind slabs last night which will likely be very stubborn to trigger in all but the steepest and most wind sheltered features. We more than likely reached peak natural avalanche activity in the evening last night. Anticipate some further loading today and possibly softer and easier to trigger pockets of wind slab this afternoon as winds abate.

WEATHER: The temperature at Pinkham Notch at this hour is hovering near zero with howling winds while the summit is in the fog with -21F with 90+ mph gusts. The hourly record of wind speeds and direction played out according to the NWS forecast models yesterday. They remained light through daylight hours and slowly shifted from the SW through the west, settling in from the NW and ramping up near nightfall. Overnight, windspeeds were in the 75-90 mph range with gusts to 115mph. Wind will calm through the day and continue from the northwest reaching the 50-70 mph range by nightfall. The temperature will warm to around -7F this afternoon.

SNOWPACK: Winds reached the speed and direction at which scouring typically occurs in northern gullies in Huntington Ravine, in upper start zones in many areas and low in the floor of Tuckerman which likely exposed the hard, icy crust that developed Tuesday night. Frigid temperatures last night and today created conditions for facet development near this crust but the hardness of new wind slab will make the slab bridge across that potential weak layer. Thinner areas of wind slab are more likely to break on early soft storm snow or perhaps weaker areas of faceted crust, but wide propagation is unlikely to occur. Heavily textured and or smooth, firm wind hammered snow will predominate the surface mid-slope. Poor visibility and cold challenges will make assessment difficult today. Looks like a trace to 2” is on its way tonight with 2-4” more tomorrow on moderating winds.

Please Remember:

  • Safe travel in avalanche terrain requires training and experience. This advisory is just one tool to help you make your own decisions in avalanche terrain. You control your own risk by choosing where, when, and how you travel.
  • Anticipate a changing avalanche danger when actual weather differs from the higher summits forecast.
  • For more information contact the Forest Service Snow Rangers, the AMC at the Pinkham Notch Visitor Center, or the caretakers at Hermit Lake Shelters or the Harvard Cabin.
  • Posted  7:50 a.m., Friday, February 10, 2017. A new advisory will be issued tomorrow.

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

2017-02-10

 

Avalanche Advisory for Thursday, February 9, 2017

This advisory will expire at Midnight.

Huntington Ravine will have HIGH and CONSIDERABLE avalanche danger today. Central, Pinnacle, Odell, and South will have High avalanche danger. Natural avalanches will become likely and human-triggered avalanches, very likely. All other forecast areas in Huntington will have Considerable avalanche danger. Natural avalanches will be possible and human-triggered avalanches likely.

Tuckerman Ravine has HIGH and CONSIDERABLE avalanche danger today. Sluice, Lip, Center Bowl, Chute, Left Gully and Hillman’s Highway will have High avalanche danger. Natural avalanches will become likely and human-triggered avalanches very likely. Lobster Claw, Right Gully, and Lower Snowfields will have Considerable avalanche danger. Natural avalanches will be possible and human-triggered avalanches likely.  Open water and ice remain exposed in the Little Headwall and the creek above. It is skiable but people have been occasionally punching through into water beneath.

 AVALANCHE PROBLEM: Wind slabs developing later today will be the primary avalanche problem. Light winds early today will allow new snow to develop into a soft, weak layer over the existing ice crust. West winds will shift northwest and ramp up through the day, ultimately building wind slabs that are likely to overcome the strength of the weak layer beneath. Natural avalanches will become increasingly likely by afternoon in leeward areas of a west or northwest wind with considerable danger even in areas with a southerly aspect. Travel in avalanche terrain later in the day is not recommended.

WEATHER: Currently, winds on the summit are in the 20 mph range from the southwest with 6F on the thermometer. Moderate snowfall began this morning on light winds at 6:30am at Pinkham Notch which is currently at 13F. Bands of precipitation on the radar show that the low pressure system to our south is likely to send the 4-6” snowfall our way pretty easily. A discussion with an NWS forecaster this morning indicates that models are incorrectly showing the wind speed and direction shift occurring 6-8 hours later than actual so make your travel decisions based on the MWObs forecast today. Expect west to northwest loading wind speeds to be blowing by noon and increasing to 50-70 mph by dark.

SNOWPACK: The 8” of snow and sleet capped by a 3cm crust is our bed surface today, at least in areas that did not avalanche. Anticipate the failure layer for avalanches later today to be the new snow falling this morning. Light winds this morning will allow new snow crystals to lay down relatively undamaged while cold temperatures will not improve settlement and bonding. Increasing wind speeds will create increasingly dense wind slabs that will grow in mass until they exceed the carrying capacity of the weak new snow below. Threading the needle today between dust on crust skiing and being swept by an avalanche will require impeccable observation skills, terrain management and a fair amount of luck. Seems like a good day to go to the resort or seek some lower elevation glades or trails in the afternoon. Our forecast areas are currently well developed so be aware of avalanches from places like Dodge Drop and Duchess to run into Hillman’s and Lower Snowfields. Avalanche path extent and the icy bed surface also indicate that dry, slab avalanches today and tonight, while not historically large, could run pretty darn far.

Please Remember:

  • Safe travel in avalanche terrain requires training and experience. This advisory is just one tool to help you make your own decisions in avalanche terrain. You control your own risk by choosing where, when, and how you travel.
  • Anticipate a changing avalanche danger when actual weather differs from the higher summits forecast.
  • For more information contact the Forest Service Snow Rangers, the AMC at the Pinkham Notch Visitor Center, or the caretakers at Hermit Lake Shelters or the Harvard Cabin.
  • Posted  8:15 a.m., Thursday, February 9, 2017. A new advisory will be issued tomorrow.

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

2017-02-09

Avalanche Advisory for Wednesday, February 8, 2017

This advisory expires at midnight.

All forecast areas of Huntington and Tuckerman Ravine have CONSIDERABLE avalanche danger. Natural avalanches are possible and human-triggered avalanches are likely. Dangerous avalanche conditions exist. Careful snowpack evaluation, cautious route-finding and conservative decision-making are essential. The exception to this is Little Headwall which has Low avalanche danger. Natural and human-triggered avalanches are unlikely.

AVALANCHE PROBLEM: The main avalanche concern today will be Wet Slab. If the weather forecast pans out and temperatures drop as slowly as predicted, avalanche danger will remain at this heightened level for most of the day as stabilization will be slow to occur. Limited visibility this morning revealed wet debris in Hillman’s Highway and some of the steeper gullies on the Boott Spur ridge. As some gullies appear to not have avalanched yesterday, these places without debris are of greatest concern. The snowpack may see an additional stresses today from possible snow and sleet as well as temperatures that are hovering around the freezing mark.

WEATHER: Steady snowfall, yesterday and overnight, delivered 7.4” (18.5cm) of snow at Hermit Lake and 8.6” (21.5cm) at the Summit. Around midnight, temperatures warmed enough to allow freezing rain and ice pellets to form. This morning, the top 1cm of snow is wet with cold dry snow beneath. Current temperatures on the mountain are around the freezing mark. With a slow moving low approaching the region, warm air will linger for the morning. An additional 1-3” of sleet and snow is expected today. Strong SW winds of 65-80mph will shift to the W and decrease to 50-70mph. Temperatures will begin to drop in the afternoon, maybe reaching single digits Fahrenheit by later tonight.

SNOWPACK: Yesterday, wind slab formed from 8” of snow and strong winds that came from multiple directions. It is likely that several locations saw avalanches during this time. Overnight, wind slab were covered with wet slab with the summit reporting six hours of ice pellets or freezing rain. Wet debris can be seen out of Hillman’s and is an obvious sign of instability. It is likely that last night and this morning a mix of newer wind slab and some older surface had to absorb the liquid, increasing the likelihood of natural activity. Additional loading today will come from a possible 1-3” of sleet and snow. There is the potential for melt water to find its way down to an ice crust and provide enough lubrication for a deeper slab to release. This should highlight the fact that even slopes that have avalanched still harbor instability. With this in mind, conservative decision-making will be crucial to safely navigate the dangerous avalanche conditions that exist.

Please Remember:

  • Safe travel in avalanche terrain requires training and experience. This advisory is just one tool to help you make your own decisions in avalanche terrain. You control your own risk by choosing where, when, and how you travel.
  • Anticipate a changing avalanche danger when actual weather differs from the higher summits forecast.
  • For more information contact the Forest Service Snow Rangers, the AMC at the Pinkham Notch Visitor Center, or the caretakers at Hermit Lake Shelters or the Harvard Cabin.
  • Posted  8:50 a.m., Tuesday, February 7, 2017. A new advisory will be issued tomorrow.

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

2017-02-08

Avalanche Advisory for Tuesday, February 7, 2017

Huntington Ravine has HIGH and CONSIDERABLE avalanche danger today. Central, Pinnacle, Odell, South, and Escape Hatch have High avalanche danger. Natural avalanches are likely and human triggered avalanches are very likely. Very dangerous avalanche conditions exist. Travel in avalanche terrain is not recommended. North, Damnation and Yale Gully have Considerable avalanche danger. Natural avalanches are possible and human-triggered avalanches are likely. Dangerous avalanche conditions exist. Careful snowpack evaluation, cautious route-finding and conservative decision-making are essential.

Tuckerman Ravine has HIGH and CONSIDERABLE avalanche danger today. Left Gully and Hillman’s Highway have High avalanche danger. Natural avalanches are likely and human triggered avalanches are very likely. Very dangerous avalanche conditions exist. Travel in avalanche terrain is not recommended. Lobster Claw, Right Gully, Sluice, Lip, Center Bowl, Chute, and Lower Snowfields have Considerable avalanche danger. Natural avalanches are possible and human-triggered avalanches are likely. Dangerous avalanche conditions exist. Careful snowpack evaluation, cautious route-finding and conservative decision-making are essential. Little Headwall has Low avalanche danger today. Natural avalanches are unlikely and human-triggered avalanches are possible. Evaluate snow and terrain carefully and identify features of concern.

AVALANCHE PROBLEM: Today, Wind Slab will form. Avalanche danger will increase as the day progresses. Accumulating snow today (up to six inches during the daylight hours today and up to another six inches tonight) along with shifting winds that will increase are obvious red flags. With winds currently shifting to the SE, the most avalanche prone slopes this morning include:  Left Gully, Hillman’s Highway and Central through Escape Hatch. As winds shift to the W during the afternoon and snowfall continues, all forecast areas will see significant loading. By nightfall, some areas rated Considerable will be pushing the upper end of that rating and when this advisory expires at midnight, all forecast areas will likely be into a High rating.

WEATHER: Strong winds from the W and WNW started Sunday and continued through Monday. Light snowfall started Monday at 4pm and has not stopped. The rate of snowfall should pick up through the morning, bringing up to 6” by nightfall. Winds are currently from the W at 39mph on the Summit and should be shifting to the S by mid-morning, and then wrapping to the SE around noon while beginning to pick up in speed. Tonight, winds will shift back to the W by midnight and with continued snowfall, we may see another 6” by Wednesday morning. A band of warm air may mix in tonight for a brief period of freezing rain.

SNOWPACK: Strong winds over the past several days sculpted our snowpack into various firm surfaces. While some old surface was exposed, most areas were covered with a one-finger (1F) wind slab. Continuous upslope snow allowed for some softer pockets of snow to form, but these are in constant flux due to winds. Today, expect widespread upside-down wind slab to form due to accumulating snowfall and increasing and shifting winds. If traveling into avalanche terrain today, keep in mind that accessing any terrain may require traveling underneath forecast zones where natural avalanches are likely today. With large snowfields connecting our forecast zones and avalanches likely overnight, we may see the runout of both Huntington and Tuckerman avalanche paths pass their current season maximum.

Please Remember:

  • Safe travel in avalanche terrain requires training and experience. This advisory is just one tool to help you make your own decisions in avalanche terrain. You control your own risk by choosing where, when, and how you travel.
  • Anticipate a changing avalanche danger when actual weather differs from the higher summits forecast.
  • For more information contact the Forest Service Snow Rangers, the AMC at the Pinkham Notch Visitor Center, or the caretakers at Hermit Lake Shelters or the Harvard Cabin.
  • Posted  8:30 a.m., Tuesday, February 7, 2017. A new advisory will be issued tomorrow.

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

2017-02-07

Avalanche Advisory for Monday, February 6, 2017

Huntington Ravine has MODERATE and LOW avalanche danger today. Central, Pinnacle, Odell, South and Escape Hatch have Moderate avalanche danger. Natural avalanches are unlikely and human-triggered avalanches are possible. All other forecast areas in Huntington have Low avalanche danger. Natural and human-triggered avalanches are unlikely.

Tuckerman Ravine has MODERATE and LOW avalanche danger today. Sluice, Lip, Center Bowl, and Chute currently have Moderate avalanche danger. Natural avalanches are unlikely and human-triggered avalanches are possible. Lobster Claw, Right and Left Gullies, Hillmans Highway, Lower Snowfields and Little Headwall have Low avalanche danger. Natural and human-triggered avalanches are unlikely.  Open water and ice remain exposed in the Little Headwall and the creek above. It is skiable but people have been occasionally punching through into water beneath.

AVALANCHE PROBLEM: Wind slabs have once again made a comeback as our primary avalanche problem. Even in the steepest and most wind-sheltered areas rated at “moderate” avalanche danger, the slabs will be stubborn to trigger but a weak layer of softer snow does exist beneath. Smaller pockets of softer wind slabs are also scattered around the terrain, mixed with the predominately firm slab. Yesterday, most surfaces were just bootable and edge-able but crampons are a good call due to the wind hammered nature of the slabs. As history shows, even the inch of snow forecast through the day on diminishing winds can drift into pockets of wind slab. Some skiable and rideable snow will exist today but in limited amounts in areas well sheltered from the high, westerly winds. Hard wind slabs of most concern may be found in the steepest terrain with drifts and sluff piles.

WEATHER: Current temperature at Pinkham Notch is 11F with 1.5” of new snow in the ground. The summit recorded 1.5” of snow overnight also with a current temperature of -8F and winds blowing from the WNW in the 65 mph range. Winds will continue to drop off a bit through the day after gusting to near 90 mph last night. Expect cold temperatures, with a high around 0F or just below on the summit with diminishing winds remaining in the 50-70mph range. Summit fog may clear a bit today and allow for improved, but not good visibility.

SNOWPACK: Recent wind velocities on the mountain have firmed up our surface slabs and made for less than ideal skiing and riding conditions. Cramponing up these slopes in the firm snow seems to be the better option though a patient and a calculated approach could result in a win for skiers in some sheltered terrain. Lots of scouring has occurred over the past 48 hours in many areas such as northern Huntington gullies, Left and Right gullies and the lower reaches of Hillmans Highway and the floor of Tucks. Between cold temperatures, strong winds, and reduced visibility, it seems like a good day to review forecast models for tomorrow’s approaching storm. Currently, 5-9” or more snow is forecast, with a southerly wind direction early in the storm. Orographic enhancement may increase snowfall to a foot. The main question is to what extent freezing rain early Wednesday morning will reach our forecast elevations, though at this time, things look promising for only a bit of ice accumulation.  Areas with a northerly aspect will continue to outpace south facing gullies in terms of total snowpack coverage as they have since the last nor’easter on December 29th filled north facing terrain.

Please Remember:

  • Safe travel in avalanche terrain requires training and experience. This advisory is just one tool to help you make your own decisions in avalanche terrain. You control your own risk by choosing where, when, and how you travel.
  • Anticipate a changing avalanche danger when actual weather differs from the higher summits forecast.
  • For more information contact the Forest Service Snow Rangers, the AMC at the Pinkham Notch Visitor Center, or the caretakers at Hermit Lake Shelters :or the Harvard Cabin.
  • Posted  8:15 a.m., Monday, February 6, 2017. A new advisory will be issued tomorrow.

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

2017-02-06

Avalanche Advisory for Sunday, February 5, 2017

This advisory expires at Midnight.

 

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

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

AVALANCHE PROBLEM: Wind Slab that has formed over the past week is becoming firmer due to sustained west winds. With 2” of new snow forecast later in the day along with increasing winds, instability will increase as the snow arrives. If traveling late in the day, be sure to evaluate terrain carefully and identify features of concern as wind slab will develop rapidly in steep areas due to strong winds. These same winds that are loading the steepest areas of our terrain with textured firm slab are also scouring the northern gullies in both Ravines. Areas with a Low rating today may contain unstable pockets around isolated terrain features.

WEATHER: Since the start of the month, the Summit has recorded 4.7” of light density snow that arrived on primarily strong west winds. A trace of snow fell yesterday with winds decreasing through the day and last night to the current W 55mph. Winds will remain steady until the afternoon when a low pressure system moves in bringing increased winds, clouds, and the potential for 2” of snow. Overnight, snow showers may continue with winds shifting to the NW and approaching the 100mph mark by daybreak tomorrow.

SNOWPACK: Our current snowpack is made of severely wind-affected snow. Areas of most concern today will be the steepest terrain in Tuckerman, wind loaded mid-elevation slopes, and underneath the ice pitches in Huntington like Central Gully. These terrain features will have areas of firm-textured wind slab sitting on top of softer wind slab underneath. This firmer wind slab will likely be thick and supportive. Identifying the edge of the slab or areas where this slab becomes thin and weak due to terrain features will be crucial to playing it safe today. Other areas in our terrain will have pockets of this same textured slab along with areas of scoured old surface. With such variability abounding, isolated terrain features will harbor pockets of unstable snow that can be avoided with careful terrain and snowpack evaluation.

The Lion Head Winter Route is open and the most direct route to the summit from the east side of the mountain. Please be on the lookout for machine traffic on the Sherburne.

Please Remember:

  • Safe travel in avalanche terrain requires training and experience. This advisory is just one tool to help you make your own decisions in avalanche terrain. You control your own risk by choosing where, when, and how you travel.
  • Anticipate a changing avalanche danger when actual weather differs from the higher summits forecast.
  • For more information contact the Forest Service Snow Rangers, the AMC at the Pinkham Notch Visitor Center, or the caretakers at Hermit Lake Shelters :or the Harvard Cabin.
  • Posted  8:20 a.m., Sunday, February 5, 2017. A new advisory will be issued tomorrow.

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

2017-02-05

Avalanche Advisory for Saturday, February 4, 2017

This advisory expires at Midnight.

Huntington Ravine has MODERATE avalanche danger today. All forecast areas in Huntington have Moderate avalanche danger. Natural avalanches are unlikely and human triggered avalanches are possible. Evaluate snow and terrain carefully to identify features of concern.

Tuckerman Ravine has CONSIDERABLE and MODERATE avalanche danger today. Sluice, Lip, Center Bowl, and Chute currently have Considerable avalanche danger. Natural avalanches are possible and human-triggered avalanches are likely. Lobster Claw, Right and Left Gullies, Hillmans Highway and Lower Snowfields have Moderate avalanche danger. Natural avalanches are unlikely and human-triggered avalanches are possible.  The only exception to this rating is the Little Headwall which has Low avalanche danger. Natural and human-triggered avalanches are unlikely there.

AVALANCHE PROBLEM: Steady snow showers and strong west winds over the past several days have created Wind Slab, a trend that will continue today. Avalanche danger will stay steady today as conditions will not favor stabilization nor increasing instability. Moderate rated areas on the south side of both ravines contain a good amount of snow and should be heeded with care; evaluate snow and terrain carefully. Right Gully and Lobster Claw have seen some scouring in the upper reaches during the steady upslope snow since the start of the month and will offer easier safe passage than other gullies with a similar rating.

WEATHER: Since Tuesday, upslope snow showers brought between 0.6” to 2.4” of snow each day. West winds averaged around 55mph, maxing out close to 90mph. Last night, winds shifted slightly to the WNW and have remained steady above 70mph since 4am this morning. Today, upslope snow will bring up to another 1” of snow as winds slowly work back to the W and decrease to around 50mph at day’s end. Approaching high pressure may allow for a period of clearing tonight and early tomorrow morning.

SNOWPACK: Multi-layered wind slab is the predominant snow surface around our terrain. Density changes in the slab were the weak interface yesterday, caused by changes in wind speed and direction. Four finger (4F) slab was showing small cracks, but no further propagation. New slab depth was 30-50cm deep in the Fan of Huntington with deeper pockets likely existing below steep terrain. With a slight shift in wind direction and increase in wind speed last night, expect this slab to become firmer. While perhaps just creating another weak interface, pockets of the 4F slab will survive and may provide a weak layer for the developing firmer (one-finger, 1F, and pencil, P) wind slab on top. These pockets will be prevalent in the steepest terrain such as the Sluice through Chute in Tuckerman as well as below terrain features like the start of ice climbs in Huntington.

The Lion Head Winter Route is open and the most direct route to the summit from the east side of the mountain. Please be on the lookout for machine traffic on the Sherburne.

Please Remember:

  • Safe travel in avalanche terrain requires training and experience. This advisory is just one tool to help you make your own decisions in avalanche terrain. You control your own risk by choosing where, when, and how you travel.
  • Anticipate a changing avalanche danger when actual weather differs from the higher summits forecast.
  • For more information contact the Forest Service Snow Rangers, the AMC at the Pinkham Notch Visitor Center, or the caretakers at Hermit Lake Shelters :or the Harvard Cabin.
  • Posted  8:10 a.m., Saturday, February 4, 2017. A new advisory will be issued tomorrow.

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

2017-02-04

Come see us at Ice Fest in North Conway

Swing by International Mountain Equipment in North Conway this afternoon from 3:30 to 5:30 when the post-climbing social hour will be going on. Some of our forecast team, including our newest recruit, Ryan Matz, will be on hand to talk snow and avalanches or to just shoot the breeze. Snow Rangers may or may not be wearing a uniform depending upon whether adult beverages are being consumed so ask around if you are not sure who is who. Tomorrow night, our own Joe Klementovich will be presenting some of his amazing photography along with some unique historical photos at 7:30pm to warm-up the crowd before the headline act starts. See you there!