Avalanche Warning – 2/18/2014

ISSUED ON February 18, 2014 at 0700 AM

The Flathead Avalanche Center is issuing a Backcountry Avalanche Warning for the entire advisory area. Heavy snowfall, strong winds, and expected continued heavy snow have created highly unstable conditions. Natural and human triggered avalanches are likely.The avalanche danger is rated HIGH on all slopes within the advisory area. Very dangerous avalanche conditions exist. Travel in avalanche terrain is not recommended and avalanche runout zones should be avoided.

This warning will either be terminated or updated by 7:00 a.m. on Wednesday, February 19.

Natural and human triggered avalanche activity has been observed over the past 72 hours.  Additional heavy snowfall and wind loading occurred Monday and Monday night continuing unstable conditions. 

 

The avalanche hazard for the all avalanche terrain within the advisory area is HIGH. We will update the advisory by 7:00 a.m. Wednesday, 2/18/2014.

Special Avalanche Advisory -2/18/2014

Issued: February 18, 2014, 7:00 a.m.
Expires: 11:59 p.m. of issue date

Good morning! This is Seth Carbonari with the Flathead Avalanche Center avalanche advisory for Tuesday, February 18, 2014. This is an unscheduled advisory due to heightened instability.  This advisory applies only to backcountry areas outside established ski area boundaries. The next scheduled advisory will be Wednesday, February 19, 2014.


MOUNTAIN WEATHER

WeatherGraphicWeather stations are reporting moderate amounts of new snow across the area in the past 24 hours with moderate to heavy winds and temperatures in the teens and 20’s.    (remote weather stations).  Stations are reporting from 0.6 inches of Snow Water Equivalent (SWE) and 5 inches of new snow at Noisy Basin SNOTEL Site to 1.9 inches of SWE and 11 inches of new snow at Stahl Peak SNOTEL Site. Precipitation appears to be heavier in the north part of the advisory area than the south.  Winds are definitely strong enough to be creating loading with winds averaging around 15 to 30 mph gusting up to 65 mph at the ridge tops.  

The National Weather Service is forecasting light snow today with the possibility of up to 5 to 9 inches of new snow at higher elevations tonight accompanied by moderate SW winds and continuing moderate temperatures.  (NWS Backcountry Forecast)

 


RECENT OBSERVATIONS

RecentObservationsGraphic

The Flathead Avalanche Center received numerous observations and reports of avalanche activity over the weekend and Monday.  This is a time where staying out of avalanche terrain is a really good idea. We received preliminary information on an avalanche in the Marias Pass area involving three skiers with no injuries. We posted an additional observation from Saturday at Stanton Mountain in Glacier National Park with a video of an Extended Column Test propagating with moderate force (2/15/2014 Stanton Mt.).   We will share additional information as we can obtain it.  An initial report from the 2/15/2014 Canyon Creek incident has been posted. 

Sadly, there was a fatality just north of the advisory area in Waterton Lakes National Park in Canada on Saturday.  (2/15/2014 Waterton)

Below are photos from a snowmobile triggered avalanche from Ten Lakes area on the the Kootenai National Forest in the northern Whitefish Range just north of our advisory area on Sunday.  One caught, no injuries. If others have had similar experiences recently, please share.

image

Snowmobile triggered avalanche in Ten Lakes area on the Kootenai National Forest. 2/16/2014

image-3

Snowmobile triggered avalanche in Ten Lakes area in Kootenai National Forest. 2/16/2014.

image-2

Human triggered avalanche in Ten Lakes area just north of advisory area in Whitefish Range. 2/16/2014.

 

 

 

 

 

 

 

 

 

 

 

 

 

 


 

SNOWPACK DISCUSSION

Avalanche Problem #1

Storm SnowThe last week has produced a substantial amount of precipitation accompanied by moderate, strong, and at times extreme winds, depositing snow on a variety of weak snow surfaces. With the addition of fluctuating snow/freezing levels, dangerous avalanche conditions developed. Natural and human caused avalanche activity continue to be reported.  Recent storm and wind slabs are very sensitive.  Given the forecast for continuing snow and snow transporting winds adding stress to already sensitive storm slabs, it would be wise to continue to avoid wind loaded terrain, steep slopes, and runout zones of avalancheh paths. Keep in mind that wind loaded terrain is not confined to ridge tops. Be aware of cross loaded features at mid elevations such as gulley walls, spur ridges, and rock bands. In wind loaded terrain, storm slabs could potentially be up to 4 feet deep or more.

 


Avalanche Problem #2

Persistent SlabLayers of weak snow (facets) still exist deeper in the snowpack. The reactivity of these layers has been variable across the advisory area, however the potential for a storm slab or wind slab avalanche to step down to these layers still exists. In areas of shallow snow a layer of weak snow also exists near the ground. It is important to dig and assess each slope for deeper weak layers before riding or skiing it as persistent slabs can be tricky and difficult to assess.

 

 

 


BOTTOM LINE

For today the avalanche hazard is rated as HIGH throughout the advisory area. This means that human triggered avalanches are very likely and natural avalanches are likely . Very dangerous avalanche conditions exist. Travel in avalanche terrain is not recommended. 

Note: We are in a period of dangerous avalanche conditions. Very cautious backcountry travel is warranted. Since February 8, avalanches have killed nine people and seriously injured three in the western United States in seven separate incidents.

High 

Note: Thank you to all of those who have submitted observations!  They have been extremely helpful during this time of heightened activity.  Keep it up!  We still really need your help. The accuracy of the avalanche advisory becomes much more robust when we have more information. Thus, observations from all of you are extremely valuable to us. Even it is just a simple email saying “Hey, we found good riding in Mountain Range X, and observed no signs of instability or recent avalanches”. This type of information is just as important as observations of avalanches. The observations need not be formal, and can remain anonymous. Don’t’ worry, we won’t give away your secret riding spot either. Call us at 406.261.9873 or email us at fac.admin@flatheadavalanche.org. Thanks for your help.

 


See recent snow profiles as well as snow profiles from the entire season here.

Join us March 14, 8:00 p.m. at Penco. We are working with the Flathead Snowmobile Association for the first in a series of motorized specific backcountry safety seminars. Details here.

Check out an interesting new research project that you can participate in about winter backcountry riding/snowmobiling and decision making from the Snow and Avalanche Lab at MSU. Details here.


Observations are extremely valuable to us. If you’ve been out in the backcountry, please drop us a line with your observations at fac.admin@flatheadavalanche.org or call 406.261.9873. Thanks!


DISCLAIMER

DisclaimerGraphic

This advisory applies only to backcountry areas outside established ski area boundaries. This advisory describes general avalanche conditions and local variations always occur. This advisory expires 24 hours after the posted time unless otherwise noted. The information in this advisory is provided by the USDA Forest Service who is solely responsible for its content.

 

 

Updated Avalanche Warning – 2/17/2014

ISSUED ON February 17 2014 at 1200 PM

The Flathead Avalanche Center is Updating the Backcountry Avalanche Warning for the Flathead Range and portions of Glacier National Park issued this morning due to continued and forecasted heavy snowfall to include entire advisory area.  Heavy snowfall, strong winds, and expected continued heavy snow have created highly unstable conditions. Natural and human triggered avalanches are likely.The avalanche danger is rated HIGH on all slopes within the advisory area. Very dangerous avalanche conditions exist. Travel in avalanche terrain is not recommended and avalanche runout zones should be avoided.

This warning will either be terminated or updated by 7:00 a.m. on Tuesday, February 18.

Natural avalanche activity was observed in John F. Stevens Canyon along the southern edge of Glacier Park Sunday and numerous human triggered avalanches have been reported over the weekend. Moderate to strong winds continue to load slopes with additional snow and the National Weather Service is calling for additional snow today and tonight with moderate winds.  

 

The avalanche hazard for the all avalanche terrain within the advisory area is HIGH. We will update the advisory by 7:00 a.m. Tuesday, 2/17/2014.

Avalanche Warning – 2/17/2014

ISSUED ON February 17 2014 at 0700 AM

The Flathead Avalanche Center is issuing a Backcountry Avalanche Warning for the Flathead Range and portions of Glacier National Park.  Heavy snowfall, strong winds, and expected continued heavy snow have created highly unstable conditions. Natural and human triggered avalanches are likely.The avalanche danger is rated HIGH on all slopes in the Flathead Range and portions of Glacier National Park within the advisory area. Very dangerous avalanche conditions exist. Travel in avalanche terrain is not recommended and avalanche runout zones should be avoided.

This warning will either be terminated or updated by 7:00 a.m. on Tuesday, February 18.

Natural avalanche activity was observed in John F. Stevens Canyon along the southern edge of Glacier Park Sunday and numerous human triggered avalanches have been reported over the weekend. Moderate to strong winds continue to load slopes with additional snow and the National Weather Service is calling for additional snow today and tonight with moderate winds.  

 

The avalanche hazard for the Flathead Range and portions of Glacier National Park within the advisory area is HIGH. All other portions of the advisory area have a CONSIDERABLE danger on all slopes. We will update the advisory by 7:00 a.m. Tuesday, 2/17/2014.

Special Avalanche Advisory – 2/17/2014

Issued: February 17, 2014, 7:00 a.m.
Expires: 11:59 p.m. of issue date

Good morning! This is Seth Carbonari with the Flathead Avalanche Center avalanche advisory for Monday, February 17, 2014. This advisory applies only to backcountry areas outside established ski area boundaries. The next scheduled advisory will be Wednesday, February 19, 2014.


MOUNTAIN WEATHER

WeatherGraphicVery little in the way of new precipitation arrived on Sunday.  Weather stations are reporting no new precipitation, temperatures have cooled a bit to the teens to 20’s and some moderate SW winds at elevation with gusts up to 65mph (remote weather stations).  The Flattop SNOTEL Site is the exception and is showing 6 inches of new snow and .9 inches of snow water equivalent in the past 24 hours. The National Weather Service out of Missoula is forecasting the possibility of up to 10 to 15 inches of new snow at higher elevations today and 5 to 8 inches at mid elevations with temperatures remaining in the upper 20’s and moderate WSW winds.

 


RECENT OBSERVATIONS

RecentObservationsGraphicSunday, we were in the Canyon Creek drainage investigating the reported avalanche from Saturday (see preliminary information). We found a melt freeze crust 10 to 18 inches from the surface and of varying hardness. On top of that crust layer we found a weak layer of small facets.  Substantial active wind loading occurred Saturday night through Sunday. We experienced one collapse in the snow pack while traveling along the ridge to the northeast of Canyon Creek. Stability testing revealed unstable results from the weak (faceted) layer above the melt freeze crust.  Extended Column Tests on a southeast slope around 5850 feet produced propagation of quality 1 with easy force.

BNSF avalanche safety reported  a natural avalanche near Shed 7 that was large enough to bury, injure or kill a person (photo1, photo2).

Sunday, we received numerous reports of instability and avalanche activity. Snowmobilers in the Skyland area near Marias Pass reported remotely triggering an avalanche on a north aspect.  Skiers and snowmobilers in the Canyon Creek drainage over the weekend reported a number of human triggered avalanches on southerly facing aspects.  We expect the avalanches reported in Canyon Creek to be running on the same melt freeze crust we encountered.  It is important to note that, not only are we encountering natural avalanches and human triggered avalanches, but we are getting reports of remotely triggered avalanches.  We also received additional reports of natural activity and instability encountered on Saturday in Essex Creek in the Flathead Range.

 Thanks to everyone who sent in observations. They are great and very valuable!

Avalanche on Skookoleel Peak. 2/15/2014.

Avalanche on Skookoleel Peak. 2/15/2014. Photo: Roehner.

Remotely triggered slide about 150 ft. wide and up to 18 inches deep. Whitefish Range. 2/15/2014. Photo: Roehner

Remotely triggered slide about 150 ft. wide and up to 18 inches deep. Whitefish Range. 2/15/2014. Photo: Roehner

Crown of natural avalanche (Class 2) in John F. Stevens Canyon, Lewis Range, Glacier National Park. 2/16/2014. Photo: BNSF Avalanche Safety  o Approximate crown width: 100 m.  o Approximate crown depth: 60 cm.  o Starting Zone Elevation: 6000 feet.  o Terminus Elevation: 4400 feet  o Starting Zone Aspect: South (135 degrees)

Crown of natural avalanche (Class 2) in John F. Stevens Canyon, Lewis Range, Glacier National Park. 2/16/2014. Photo: BNSF Avalanche Safety

 

Debris of natural avalanche (Class 2.5) in John F. Stevens Canyon, Lewis Range, Glacier National Park. 2/16/2014. Photo: BNSF Avalanche Safety.  o Approximate crown width: 100 m.  o Approximate crown depth: 60 cm.  o Starting Zone Elevation: 6000 feet.  o Terminus Elevation: 4400 feet  o Starting Zone Aspect: South (135 degrees)

Debris of natural avalanche (Class 2.5) in John F. Stevens Canyon, Lewis Range, Glacier National Park. 2/16/2014. Photo: BNSF Avalanche Safety.

Crown of natural avalanche (Class 2.5) in John F. Stevens Canyon, Lewis Range, Glacier National Park. 2/16/2014. Photo: BNSF Avalanche Safety o Approximate crown width: 30 m.  o Approximate crown depth: 60 cm.  o Starting Zone Elevation: 6000 feet.  o Terminus Elevation: 5000 feet  o Starting Zone Aspect: South (180 degrees)

Crown of natural avalanche (Class 2.5) in John F. Stevens Canyon, Lewis Range, Glacier National Park. 2/16/2014. Photo: BNSF Avalanche Safety

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 


 

SNOWPACK DISCUSSION

Avalanche Problem #1

Storm SnowThe last week has produced a substantial amount of precipitation accompanied by moderate, strong, and at times extreme winds, depositing snow on a variety of weak snow surfaces. With the addition of fluctuating snow/freezing levels, dangerous avalanche conditions developed. Natural and human caused avalanche activity continue to be reported.  Recent storm and wind slabs that have not had time to gain strength are still waiting for added stress to tip the scale and more snow is in the forecast.  Given the forecast for continuing snow and snow transporting winds adding stress to already sensitive storm slabs, it would be wise to continue to avoid wind loaded terrain, steep slopes, and convex rollovers. Keep in mind that wind loaded terrain is not confined to ridge tops. Be aware of cross loaded features at mid elevations such as gulley walls, spur ridges, and rock bands.

 


Avalanche Problem #2

Persistent SlabLayers of weak snow (facets) still exist deeper in the snowpack. The reactivity of these layers has been variable across the advisory area, however the potential for a storm slab or wind slab avalanche to step down to these layers still exists. In areas of shallow snow a layer of weak snow also exists near the ground. It is important to dig and assess each slope for deeper weak layers before riding or skiing it as persistent slabs can be tricky and difficult to assess.

 

 

 


BOTTOM LINE

For today the avalanche hazard is rated as HIGH throughout the advisory area. This means that human triggered avalanches are very likely and natural avalanches are likely . Continue to pay close attention to changing conditions and be prepared to alter plans if conditions warrant. Travel in avalanche terrain is not recommended. 

Note: We are in a period of tricky and dangerous avalanche conditions. Very cautious backcountry travel is warranted. Since February 8, avalanches have killed six people and seriously injured three in the western United States in five separate incidents.

High 

Note: Thank you to all of those who have submitted observations!  They have been extremely helpful during this time of heightened activity.  Keep it up!  We still really need your help. The accuracy of the avalanche advisory becomes much more robust when we have more information. Thus, observations from all of you are extremely valuable to us. Even it is just a simple email saying “Hey, we found good riding in Mountain Range X, and observed no signs of instability or recent avalanches”. This type of information is just as important as observations of avalanches. The observations need not be formal, and can remain anonymous. Don’t’ worry, we won’t give away your secret riding spot either. Call us at 406.261.9873 or email us at fac.admin@flatheadavalanche.org. Thanks for your help.

 


See recent snow profiles as well as snow profiles from the entire season here.

Join us March 14, 8:00 p.m. at Penco. We are working with the Flathead Snowmobile Association for the first in a series of motorized specific backcountry safety seminars. Details here.

Check out an interesting new research project that you can participate in about winter backcountry riding/snowmobiling and decision making from the Snow and Avalanche Lab at MSU. Details here.


Observations are extremely valuable to us. If you’ve been out in the backcountry, please drop us a line with your observations at fac.admin@flatheadavalanche.org or call 406.261.9873. Thanks!


DISCLAIMER

DisclaimerGraphic

This advisory applies only to backcountry areas outside established ski area boundaries. This advisory describes general avalanche conditions and local variations always occur. This advisory expires 24 hours after the posted time unless otherwise noted. The information in this advisory is provided by the USDA Forest Service who is solely responsible for its content.

 

 

Observation -12/26/2013- John F. Stevens Canyon, Lewis Range, GNP

BNSF RAILWAY AVALANCHE SAFETY

VOLUNTARY FIELD OBSERVATIONS 

 

DATE

SUBMITTED:

TIME SUBMITTED:

OBSERVATION LOCATION

OBSERVATION

DATE:

SUBMITTED BY:

12/26/2013

1630

Shed 4C

12/26/2013

Dundas

 

                                                                                                                                                                                                      

 

 

 

GENERAL INFORMATION:

Toured up to the starting zone of Shed 4C (Burnout). Objective was to conduct a full profile at a mid-elevation starting zone to compare this snowpack to the profile that I conducted last week.  Warm air temps and high humidity were responsible for making the surface snow wet, heavy and sticky from the valley floor to my pit location at 5300’.  Numerous wet loose “rollerballs” occurred both naturally and were triggered by tree bombs, uphill and downhill skiing.

WEATHER OBSERVATIONS:

  • Overcast skies.
  • Light west winds. 
  • Warn air Ts throughout the day with Ts above freezing in the valley floor and at the pit location.
  • Surface snow had been worked over by recent Southwest winds.

SNOWPACK OBSERVATIONS:

Conducted full-depth snow profile on a 35 degree slope at 5300 ft elevation.  Aspect was 1200 and HS= 81 cm.  Snowpack was moist throughout and WEAK!  Boot penetration was to the ground at the pit location.  Snowpack consists of 2 thin crusts located 16 cm and 54 cm from the ground.  These crusts are sandwiched by weak layers of facets, mixed forms, rounds and depth hoar

Layer of greatest concern is a 5 cm layer of 1.0mm facets located directly above the lowest crust. 

Significant T gradient was recorded only in the upper 10 cm of the snowpack. 

Stability test consisted of ECTsand CTs.  No propagation was observed in the ECT tests.  CT tests revealed failure in 4 distinct layers. 

CT 6,8,8 Q2@ 55 cm from ground on top of the uppermost crust

CT13,15,16 Q2@ 43 cm from ground in a 16 cm layer of 4F mixed forms

CT 21,22 22 Q2@ 21 cm from ground in a 5cm layer of facets sandwiched between depth hoar and a 1F slab

CT 23,23,25 Q2 @ 15 cm from ground in a 15 cm layer of depth hoar 

AVALANCHE OBSERVATIONS:

No slab avalanche activity observed.  Numerous wet loose rollerballs observed that entrained only the surface snow.

BNSF AVALANCHE SAFETY FIELD OBSERVATIONS SUBMITTED TO FLATHEAD AVALANCHE CENTER AND GLACIER NATIONAL PARK ARE BEING PROVIDEDED IN ACCORDANCE WITH THE TERMS AND CONDITIONS SPECIFIED GLACIER NATIONAL PARK SPECIAL USE PERMIT.  

THESE OBSERVATIONS REPRESENT SITE SPECIFIC INFORMATION INTENDED FOR THE BNSF AVALANCHE SAFETY PROGRAM AND IN NO WAY ARE TO BE CONSTRUED AS A PUBLIC/ RECREATION AVALANCHE FORECAST. 

Avalanche Advisory – 12/25/13

THIS ADVISORY HAS EXPIRED

Issued: Dec. 25, 2013, 7:00 a.m.
Expires: 11:59 p.m. of issue date

Good morning and Merry Christmas! This is Seth Carbonari with the Flathead Avalanche Center avalanche advisory for Wednesday, December 25, 2013. This advisory applies only to backcountry areas outside established ski area boundaries. The next scheduled advisory will be Saturday, December 28, 2013.


MOUNTAIN WEATHER

WeatherGraphic

Since Sunday the area has seen snow accumulations of 4 to 10 inches and temperatures have been moderated to highs near freezing and lows in the 20’s and high teens. We have seen south west ridge top winds at 10 to 20 mph with gusts in the 30s. Currently mountain temperatures are 15 to 21 F. Today appears to be starting out with clear skies, but the forecast calls for partly cloudy to broken skies with no precipitation expected and ridge top winds 10 to 20 mph from the south west.


RECENT OBSERVATIONS

RecentObservationsGraphic

Tuesday we traveled along Skookaleel Ridge in the Whitefish Range.  Numerous small, natural, soft slab avalanches were discovered on steep terrain (photo).  Also reported on Fiberglass Hill, these avalanches were at a new snow interface, very soft slab in nature, on very steep (>40 degree) slopes and had 2 to 4 inch crowns.  Winds were light to moderate at ridge top, where we encountered some weak wind slabs.  Pit results on a South aspect at 6660′ showed about 10 to 15 cm of heavier new snow on top of the lighter snow received over the weekend (snow profile).  Stability tests identified a weak interface within the new snow that took light to moderate force to cause to fail but we were unable to get to propagate in Extended Column Tests.  We were not able to trigger any avalanches on test slopes. Reports from the John F. Stevens Canyon indicated no new avalanche activity observed there on Tuesday.  Monday, observations from Canyon/Cascadilla up the Middle Fork indicateed a larger degree of instability with observers able to trigger small avalanches in the heavier new snow that was on top of the lighter, older snow.

 


SNOWPACK DISCUSSION

Avalanche Problem #1

Wind Slab

Wind slabs have been forming near ridge tops and forecasted winds will continue their development. Slopes below newly developed cornices or adjacent to scoured windward slopes can potentially harbor these wind slabs.

 

 

 


Avalanche Problem #2

Storm SnowRecent new snow has shown its willingness to slide over the past couple of days as it came in heavier than the surface snow.  Although the threat should be moderating over time and with no precipitation in the forecast, this is still a potential problem.

 

 

 

 


Avalanche Problem #3

Persistent Slab

The weak layer of facets and buried surface hoar still exists thoughout the area from 1.5 to 2.5 feet down above and below crust layers.  Continue to dig down looking for these weak layers prior to committing to a slope.

 

 

 


BOTTOM LINE

Overall, the avalanche hazard is MODERATE. This means that heightened avalanche conditions exist and human triggered avalanches are possible particularly on steep wind loaded slopes and in areas where faceted layers and lingering buried surface hoar are present above and below crust layers. Expect sluffing to occur on steep slopes with cohesionless recent snow as well.

Moderate

 


MEDIA

 

 

 

OLYMPUS DIGITAL CAMERA

12/24/13 Small slides in Canyon Creek

 

image

12/24/13 Skookaleele Ridge Snow Profile

 


Observations are extremely valuable to us. If you’ve been out in the backcountry, please drop us a line with your observations at fac.admin@flatheadavalanche.org or call 406.261.9873. Thanks!


DISCLAIMER

DisclaimerGraphicThis advisory applies only to backcountry areas outside established ski area boundaries. This advisory describes general avalanche conditions and local variations always occur. This advisory expires 24 hours after the posted time unless otherwise noted. The information in this advisory is provided by the USDA Forest Service who is solely responsible for its content.

 

 

12/8/13 Avalanche Incident–Noisy Basin, Swan Range

Noisy Basin Avalanche Incident Report

Swan Range, MT

Date of Avalanche: 8 December 2013

Date of Investigation: 10 December 2013

 

 

INCIDENT SYNOPSIS

On Sunday, December 8, 2013, a party of two skiers was traveling in the Noisy Basin area near Camp Misery in the Swan Range, MT.  At approximately 1500, both skiers were descending a slope when they tritggered and avalanche that failed approximately 100 feet above them.  Skier #1 (a 36 year old male) was caught in the avalanche, carried downslope approximately 300 to 400 feet through some trees, lost one ski, and came to rest buried up to his neck in the snow.  He sustained a broken nose, lacerations to the face that required six stitches, multiple contusions and bruises, and a minor injury to his leg.  Skier #2 (a 35 to 40 year old male)was following a few turns behind Skier #1 and was also caught in the avalanche.  Skier #2 was carried downslope, sustained an injury to his knee when one of his skis was torn off, but was not buried.  Skier #2 was able to find Skier #1 downslope and dig him out.  They called a friend via a mobile phone to come help them with a snowmobile and slowly worked their way to the road to meet him. At this point they were able to depart for the trailhead.  An attempt at a site investigation occurred on Dec. 10 by Flathead Avalanche Center staff, but the site could not be located due to new snowfall and dangerous avalanche conditions. The information contained in this report became available on December 18. The avalanche occurred on a west facing aspect within a defined avalanche path.  The reported crown depth was approximately 8 to 10 inches, with a crown width of approximately 150 feet and ran approximately 500 vertical feet.  Approximate elevation of the crown was 6400 feet and the toe of the debris was 6200 feet (Figure 1).  The United States classification of the avalanche is SS-ASu-R4-D2-U (Greene e al. 2010).

 

 

noisy_12_8_13b 

Figure 1: Avalanche location in relation to Camp Misery and 12/14/13 avalanche

 

WEATHER AND SNOWPACK

December 8 was cold and clear in Noisy Basin with winds from the north/northwest at approximately 10 to 15 mph.  The week leading up to the incident was notably cold and dry with the presence of an arctic air mass, no new precipitation and temperatures averaging -15 to -25 degrees Fahrenheit.  The last significant snowfall was over a week previous to the incident (Figure 2).  The nearest remote weather station is Noisy Basin SNOTEL site, but this site lacks a wind sensor. However, based on other remote stations in the region and field observations, winds in the 48 hours prior to the incident were generally in the 15 to 20 mph range, gusting to 30 out of variable directions that included a substantial amount of time out of the north-northeast.  The skiers reported seeing wind slabs at Picnic Notch and also seeing a good deal of scour along the ridgeline to the south of Picnic Notch. 

 

 weather

Figure 2: Air temperature, snow water equivalent (inches) and snow depth (inches) from Noisy Basin SNOTEL site (elev. 6040 ft.) from December 1 to December 8, 2013. The incident took place on December 8, 2013.

 

 

AVALANCHE

The Flathead Avalanche Center Advisory for December 8 read:

“Overall, the avalanche hazard is MODERATE.  This means that human triggered avalanches are possible particularly on steep slopes with sensitive wind slabs and in isolated areas where buried surface hoar and crust layers are more reactive.”

 

The advisory listed WIND SLABS as an avalanche problem and identified possible atypical loading patterns due to north to northeast winds. No other avalanche activity was reported in the area during this time. One snowmobiler reported wind affected snow on convex rollovers near creek beds in the area.

 

Flathead Avalanche Center Staff received a very vague report of a skier triggered avalanche the evening of Sunday, December 8, 2013.  Staff spoke to the reporting party, who had no details on location or identity of those involved.  Flathead Avalanche Center staff members attempted to locate the avalanche site on December 10, but were unable because of new snowfall and dangerous avalanche conditions.  FAC staff continued to receive ambiguous reports on the incident until they obtained contact information and were able to contact the involved parties on December 18.  All information in this report is solely based on reports from the two parties involved. Flathead Avalanche Center staff last visited this area (Noisy Basin) on Friday, December 6.

 

From information received from the two skiers involved in the incident, the crown depth was approximately 8 to 10 inches (20-25 cm) deep and approximately 150 feet (45 m) wide and the slide ran approximately 500 feet (150 m) vertically.  Elevation of the crown was approximately 6400 feet (1950 m) and the toe of the debris approximately 6200 feet (1890 m).  The United States classification of the avalanche is SS-ASu-R4-D2-U (Greene e al. 2010). Because of the inability to conduct a crown profile, we can only speculate on the snowpack at the time of the incident using information from the skiers and other observations.  We speculate that the slope had some degree of wind loading from the previous days’ north and northeast winds and that the weak layer was an interface within that wind loaded portion of the snowpack. 

 

Skier #1 (36 year old male on telemark skis without straps) and Skier #2 (35 to 40 year old male on alpine skis) parked their vehicle at the Switchback Trail (#725) Trailhead around 1200 on Noisy Basin Road and skinned up the road from there.  They had planned on a quick tour, mostly for exercise and anticipated staying mostly within treed terrain.  Skier 2 checked the avalanche advisory in the morning and both were carrying a beacon, shovel and probe.  They consider themselves accomplished skiers with a good deal of experience in avalanche terrain, but have no formal avalanche education.  They ascended to Picnic Notch, noting some wind slabs in the notch, and continued south along the ridge to the slope they descended.  They descended through the trees to the opening where the avalanche occurred, catching it downslope of their intended location.  Skier #1 entered the opening (approximately 400 yards vertical by 100 yards wide) around mid-slope and found the snow “surprisingly good” his first couple of turns.  Skier #2 followed Skier#1 closely and made two turns before he realized the snow was moving.  Skier #1 made a few turns before everything started to move.  The slope had failed somewhere above him, approximately 100 feet.  Skier #1 was caught in the avalanche, carried downslope head first and struggled to swim. Skier #1 stated that after about 5 seconds, it “felt like someone hit me with a 2×6 across the face.” He was strained through some trees at the bottom and came to a stop after another 3 to 5 seconds.  Skier #1 came to rest in an upright position, buried up to his neck after being carried approximately 300 to 400 feet downslope.  He could breathe, but not move.  He had lost one ski, of which the binding had broken (Figure 3), and both poles, but one ski remained attached.  He received a broken nose, lacerations to the face which required 6 stitches, multiple bruises and contusions, and a minor leg injury.

Skier #2 provided this account:

 “My friend dropped in first and he made a turn in soft snow that looked great. I dropped in immediately after to make some 8s. I made two turns before I realized the snow was moving too. I stayed on top as I tried to head for the trees on my right as a possible safe zone when I realized I wasn’t getting there and it would take me more into the slide. I tried to go left and my ski got yanked off and my knee popped.  I tried to stay on top with my one remaining ski when I got tossed. The snow stopped and I wasn’t buried. I checked myself for injury and looked uphill to where I last saw my partner. I called out but didn’t hear a response. I scanned uphill for equipment a hand or anything when I heard him yell. I still thought he was above me when he yelled again and said “below you, hurry”. I scooted down on my one ski and grabbed his loose ski on my way to find him partially buried and pressed against a tree. He was bloody and moving slow. I dug out his legs and took off his one remaining ski. We called family and friends that headed up jewel basin road to get us at camp misery. My friend and I each hobbled down on one leg back to the road.”

 

Skier #2 lost one ski and a GOPRO camera.  His knee has some muscle damage that will keep him from skiing for approximately a month.

 

Ski Binding 2013 Avy 

Figure 3: Broken binding on Skier #1’s telemark ski

 

We appreciate both skiers speaking with us and sharing the details of the event so that they may be used to inform and educate others.  They also shared some of their lessons learned, in their own words below:

Lessons Learned (we have all heard before but reiterate):

-Commence descent of prone areas from the start zone as opposed to mid-slope to increase ability to keep the slide/slough debris downhill and find a safe exit.

-Descend one at a time and spaced apart.     

-Route Selection-It doesn’t take a lot of snow or a large exposed slope to result in a deadly slide.  Slide occurred on small exposed gash within generally treed/gladed area.  Trees/Anchors are a good thing unless you are being strained through them. 

-Familiarity-Both skiers can access this area from their living rooms.  It is easy to get complacent, especially with minimal early season snowpack and a generally unexposed route previously skied in all kinds of varying conditions and points during the year.”

 

 

SEARCH AND RESCUE

No search and rescue operations were initiated as the skiers were able to extricate themselves and return to their vehicles with some help from a friend with a snowmobile.

Direct any questions regarding this report to fac.admin@flatheadavalanche.org or 406.261.9873.

Report prepared by Seth Carbonari and Erich Peitzsch of the Flathead Avalanche Center.

REFERENCES
Greene, Ethan M., D. Atkins, K. Birkeland, K. Elder, C. Landry, B. Lazar, I. McCammon, M. Moore, D. Sharaf, C. Sterbenz, B. Tremper, and K. Williams, 2010. Snow, Weather, and Avalanches: Observational Guidelines for Avalanche Programs in the United States.  American Avalanche Association, Pagosa Springs, CO: Second Printing Fall 2010, 152 pp.

 

Avalanche Advisory – 12/15/2013

THIS ADVISORY HAS EXPIRED

Issued: Dec. 15, 2013, 7:00 a.m.
Expires: 11:59 p.m. of issue date

Good morning! This is Seth Carbonari with the Flathead Avalanche Center avalanche advisory for Sunday, December 15, 2013. This advisory applies only to backcountry areas outside established ski area boundaries. The next scheduled advisory will be Wednesday, December 18, 2013.


MOUNTAIN WEATHER

WeatherGraphic

Temperatures warmed through the week, approached the freezing mark in many areas on Saturday and are still just below freezing at higher elevations. Winds also have been on the increase as some sensors at higher elevations are reporting gusts in excess of 70 mph this morning. Snow showers were light in the mountains Saturday with snow water equivalents measuring 0.4” at both Flattop and Noisy Basin SNOTEL sites. Temperatures should stay on the warm side for Sunday into the first part of the week with small gains in precipitation.  The National Weather Service is predicting strong West to Southwest winds for Sunday with the possibility of 40 to 50 mph gusts above 6000′.


RECENT OBSERVATIONS

RecentObservationsGraphic

On Saturday, Erich was in the Paola Ridge area in the Middle Fork and I was in the Peter’s Ridge area in the Swan Range (snow profile). No recent avalanche activity or signs of instability were noted at either location, but visibility was challenging.  Snow was being steadily transported above 5000’.  Stability tests at Peter’s Ridge and on North aspects in Paola creek produced little results.  On the South aspect in Paola Creek, repeated extended column tests propagated across the column with moderate force (video).  This problem layer has persisted and continues to gain loading on top of it.  We also received a report from Penrose Ridge in the Middle Fork with similar observations on north aspects.

A skier triggered an avalanche and was caught and fully buried except for one arm near Picnic Notch in Noisy Basin on Saturday.  The skier was able to self-rescue without any injuries.  The skier estimated the avalanche to have a crown of 2 feet, stretch 200 to 300 feet across the slope and run approximately 200 feet vertical.  We hope to visit the site Sunday and will provide additional information as we are able.  This incident is a great reminder that while some aspects and locations are exhibiting few signs of instability, others can be very sensitive.     

Avalanche Problem #1

Wind Slab

Strong winds and consistent snowfall during the past week have developed substantial wind slabs within the advisory area. The formation of wind slabs from previous days also exists within the underlying cold snow pack. These wind slabs sit on multiple weak faceted layers. Some of these weak layers are buried deep in the snowpack and may be difficult to trigger but the potential exists that even a small wind slab could subsequently trigger an avalanche in these deeper layers.  

 


Avalanche Problem #2

Persistent SlabObservations and stability tests still reveal persistent
weak layers such as surface hoar and facets buried 2′ deep in the snowpack (video). The additional loading will add stress to these layers. Continue to carefully evaluate these layers prior to skiing or riding a slope. This weak layer is not to be trusted. The only way to know if this layers exists and how reactive it might be is to dig down and check it out. 

 

 

 


BOTTOM LINE

For today, the avalanche hazard is CONSIDERABLE on wind loaded slopes steeper than 30 degrees. The hazard is MODERATE on all other slopes. This means that human triggered avalanches are likely on steep slopes with sensitive wind slabs and possible on other slopes where facets and surface hoar still exist about 2 feet below the surface.

Considerable

Moderate

 


MEDIA

 

 


Observations are extremely valuable to us. If you’ve been out in the backcountry, please drop us a line with your observations at fac.admin@flatheadavalanche.org or call 406.261.9873. Thanks!


DISCLAIMER

DisclaimerGraphicThis advisory applies only to backcountry areas outside established ski area boundaries. This advisory describes general avalanche conditions and local variations always occur. This advisory expires 24 hours after the posted time unless otherwise noted. The information in this advisory is provided by the USDA Forest Service who is solely responsible for its content.