Avalanche Advisory – 4/5/2014

THIS ADVISORY HAS EXPIRED.

Issued: April 5, 2014 at 7:00 a.m.
Valid Until: 11:59 p.m. of issue date

Good morning! This is Todd Hannan with the Flathead Avalanche Center avalanche advisory for Saturday, April 5, 2014. This advisory applies only to backcountry areas outside established ski area boundaries. This is the final scheduled advisory for the season.


MOUNTAIN WEATHER

WeatherGraphicYesterday, a storm moved through the area that brought gusty winds and left 2-7 inches of new snow that measured 0.2-0.5 inches of snow water equivalent.  Daytime high temperatures only reached the mid-30s compared to the mid-40s in the previous days. Currently, remote weather stations and SNOTEL sites are reading 28 to 32 °F with winds out of the southwest at 10-25 mph with gusts to 32 mph. Today should see partly/mostly cloudy skies with temperatures in the upper 20s to mid-30s. Light snow showers are expected through the day, increasing tonight with accumulations of 4-6 inches by tomorrow morning. Winds will be out the west and southwest 5-15 mph later this morning, increasing to 15-30 mph in the afternoon.

 


RECENT OBSERVATIONS

RecentObservationsGraphicYesterday we were in Noisy/Jewel Basin in the Swan Range. The morning was foggy and visibility was obscured, winds on the ridge were moderate to strong. There was minimal drifting of the snow (before snowfall began) since snow on the Leeward slopes was still locked up in previously formed surface crusts. The melt-freeze crust that we traveled on was supportable above 6200 feet and was present on all terrain that had slight sun exposure. Though short lived, the snow came in with moderate to heavy intensity, at times snowfall rates approached 2 inches per hour. Visibility improved in the afternoon and we could see several run outs from large south facing slide paths and no recent avalanche activity was observed. We did observe lots of roller ball activity from previous days, even on shaded aspects (photo).  Snow profiles and stability testing revealed some instability within the top foot of the snow pack, associated with melt-freeze crusts and graupel layers (profile, photo). None of these failure layers propagated fractures in extended column tests.

Glide cracks are beginning to rear their ugly heads again this spring. Erich noted a couple of glide cracks recently in the Swan Range (photo), and Glacier National Park rangers noted a few in the park.

General snow profile on north aspect at 6200 feet. Noisy Basin, Swan Range 4/4/2014

General snow profile on north aspect at 6200 feet. Noisy Basin, Swan Range 4/4/2014


Roller balls on north aspect. Noisy Basin, Swan Range. 4/4/2014

Roller balls on north aspect. Noisy Basin, Swan Range. 4/4/2014


New snow and graupel drifting along ridgeline in Noisy Basin, Swan Range. 4/4/2014

New snow and graupel drifting along ridgeline in Noisy Basin, Swan Range. 4/4/2014

 

 

 

 

 

 

 

 

 

 


SNOWPACK DISCUSSION

Avalanche Problem #1

Wind SlabEven with estimated wind speeds of around 25 mph along the ridgeline in Noisy Basin yesterday, we did not observe snow being transported prior to the onset of the new snow. This was due to the strong melt-freeze crust on windward slopes at our location. At high elevations where snow remained soft and available for transport, I expect wind slabs to be thicker and they should be avoided until they have had time to settle. Also remember that at lower elevations even shallow wind slabs can have big consequences if you are traveling in exposed terrain and in or above terrain traps. It remains important to assess the stability of each slope you intend to ski or ride.

 

 

 


 

Avalanche Problem #2

Deep SlabThough rather isolated in distribution and difficult to trigger the consequence of triggering a deep slab at this point would be catastrophic. In most locations we continue to find areas with shallow snow that harbor weak snow near the ground, as well as the thick rain crust from early March. Neither of these have been recent players, but they are still out there and deserve a cautious approach. Don’t let your guard down when assessing slopes for deep slab instabilities this spring and continue to avoid terrain with the highest probability of triggering these slabs such as steep rocky terrain, convex rollovers, and shallow wind scoured areas.

 


 

 

Spring can bring a mixed bag of weather and snow conditions. It is important to pay attention to rapidly changing conditions as weather can greatly affect snow and avalanche conditions this time of year. Pay particular attention to rapidly rising temperatures or extended periods of direct sun exposure. While temperatures are not expected to get excessively warm today, it is important to remember that rapid warming and above freezing temperatures will increase the wet avalanche hazard. Even small avalanches can be dangerous when traveling in or above terrain traps. Cornices can also become more sensitive during the spring when they are exposed to direct sun exposure and warmer temperatures. Assess a ridge line suspected of having cornices from multiple angles before approaching to ensure that you will not be standing on top of one. When cornices are present below, stay well behind confirmed solid ground as they can break farther back than what might be expected and avoid traveling below them.

 


BOTTOM LINE

For today the avalanche hazard is LOW below 5500 feet. This means that human triggered and natural avalanches are unlikely, however normal caution and safe travel practices should still be exercised. Terrain above 5500 feet is rated as MODERATE, human triggered avalanches are possible, particularly on slopes steeper than 35 degrees that have a shallow snowpack. There are also pockets of CONSIDERABLE hazard in wind loaded terrain, steeper than 35 degrees, and above 6500 feet.  Human triggered avalanches are likely in this terrain. With substantial new snow expected tonight and into tomorrow, accompanied by moderate to strong winds, expect avalanche hazard to rise tomorrow. Be sure to check back this evening as we will post a spring avalanche statement.

 

Moderate_2

Low 

Considerable

 


Personal Note:

I want to personally thank those of you who took the time after a long day of skiing, riding, or working in the backcountry to send us your observations. These are invaluable in confirming suspicions, making us aware of localized events, and general  reduction of the uncertainty associated with a large advisory area. Thank you. I hope all of you have a great and safe spring and summer.

 


 

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


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 – 4/3/2014 – Essex Creek drainage, Middle Fork, Flathead Range

From: Steven Zwisler

Date: 4/3/14

Time: 0900-1600

Location: Essex Cr

Activity: Skiing

 

 

Snowpack Observations:

 

Skied to the head of Essex Cr and descended the trees below the Adams/Cameahwait saddle in old dense snow and nearly corn. We could not hit ground with a 10 ft probe at 6,400 ft. The snow pack was upside down at 6,400 ft. There was no settling, cracking, or other alarms. We saw no current avalanche activity but did we ever see some impressive history. All the slide paths off Essex Mt into Essex Cr had gone big with several damning the creek and some lobes turning to go down the valley. There were slides in the woods below cliff bands. A slide came down the big opening off the back side of Snowshed that meets Essex Cr at 4,800 ft, crossed the creek, and extended down valley. There were new wet slides on top of the old debris though the newer slides did not reach the creek or the summer trail. Cameahwait and Adams had old visible triangle shaped crowns and debris trains. The one from Cameahwait went to 5,200 ft. Peak 7,854 had old slides in its west facing glades where I have never seen avalanches in the 33 years I have skied in the Essex drainage. All in all a sobering reminder of what can happen. Oh, it was also a beautiful spring day.

Avalanche Advisory – 4/2/2014

THIS ADVISORY HAS EXPIRED.

Issued: April 2, 2014 at 7:00 a.m.
Valid Until: 11:59 p.m. of issue date

Good morning! This is Todd Hannan with the Flathead Avalanche Center avalanche advisory for Wednesday, April 2, 2014. This advisory applies only to backcountry areas outside established ski area boundaries. The next scheduled advisory will be Saturday, April 5, 2014.


MOUNTAIN WEATHER

WeatherGraphic Yesterday saw partly cloudy skies with isolated light snow showers. Flattop Mountain SNOTEL site was the warm spot, with a high temperature of 42°F. Currently, remote weather stations and SNOTEL sites are reading 11 to 29 °F with winds out of the east at 3-5 mph. Today will see partly cloudy skies with temperatures from upper 20s to mid-30s. Light snow showers are possible this afternoon and winds will shift to 5-10 mph out of the west.

 


RECENT OBSERVATIONS

RecentObservationsGraphicYesterday Tony and I traveled into the Swede Creek drainage in the Whitefish Range. The snow surface on our ascent was a supportable melt-freeze crust on any aspect that was previously exposed to the sun. Temperatures remained relatively cool with a light breeze and intermittent clouds to keep the sun at bay. It wasn’t until late in the afternoon that the snow surface began to show signs of melting (photo). We observed some roller balls/pinwheels from steep, sun exposed slopes. In the shade, the snow remained dry and unconsolidated. A snow profile on a south aspect revealed multiple crusts in the upper snowpack that were minimally reactive to stability tests. In an area with a relatively shallow snowpack we found weak faceted snow near the ground.

Skiers in the Pike Creek drainage in the Flathead Range and in the Apgar Range last weekend encountered difficult travel conditions due to warm heavy snow and breakable crusts (observation). On Monday, skiers in the Marion/Dickey Creek drainages in the Flathead Range noted sun affected snow on solar aspects and surface snow that remained cool and dry in the shade (observation).

Glide cracks are beginning to rear their ugly heads again this spring. Erich noted a couple of glide cracks last Friday in the Swan Range (photo), and Glacier National Park rangers noted a few in the park.

Large cornices along ridgeline. Notice small woodland creature ignoring safe travel protocol around cornices. Swede Creek, Whitefish Range. 4/1/2014

Large cornices along ridgeline. Notice small woodland creature ignoring safe travel protocol around cornices. Swede Creek, Whitefish Range. 4/1/2014


Roller balls on steep slopes indicate that surface snow is starting to become wet. Swede Creek, Whitefish Range. 4/1/2014

Roller balls on steep slopes indicate that surface snow is starting to become wet. Swede Creek, Whitefish Range. 4/1/2014


An early sign that snow surface is becoming moist.  Swede Creek, Whitefish Range. 4/1/2014

An early sign that snow surface is becoming moist. Swede Creek, Whitefish Range. 4/1/2014

 

 

 

 

 

 

 

 

 

 

 

 


SNOWPACK DISCUSSION

Avalanche Problem #1

WetAvalGiven the time of year with longer days and increasing sun intensity, pay close attention to the effects of warming and direct sun on the snow surface. Today the wet avalanche hazard should be confined to slopes that receive prolonged direct sun exposure. Consider moving to a shaded aspect if the snow surface becomes wet and surface crusts begin to melt. Avoid steep sun exposed slopes, particularly when traveling in or above terrain traps.

 

 


 

Avalanche Problem #2

Wind SlabWind slabs can take up to a week to gain strength. Moderate to strong winds last weekend formed sensitive wind slabs and though they are moving in the direction of stability, steep wind loaded slopes should still be treated as suspect. Pockets of recently formed wind slabs were deposited on top of layers of graupel, and though this is not considered a persistent weak layer they can take a bit longer to gain strength. It remains important to assess the stability of each slope you intend to ski or ride. Additionally, large cornices exist in the area (photo), and with warming temperatures this time of year they can become particularly sensitive. Even short periods of more intense sun can make them unstable. Give cornices a wide berth when traveling above them and avoid travel below.

 


Avalanche Problem #3

Deep SlabIt’s getting late in the season, spring is in the air, and we have been talking about deep persistent slab for months. We continue to find areas with shallow snow that harbor weak snow near the ground, as well as the thick rain crust from early March. Neither of these have been recent players, but the consequence of triggering an avalanche in these deep slabs remains high. Prior to committing to a slope ask yourself, “where would I be most likely to trigger a deep slab?” More often than not, the answer will be on that steep rollover or in areas notorious for having a shallow snowpack like near those exposed rocks. Don’t let your guard down when assessing for deep slab instabilities and continue to avoid terrain with the highest probability of triggering these slabs .

 


 

Spring can bring a mixed bag of weather and snow conditions. It is important to pay attention to rapidly changing conditions as weather can greatly affect snow and avalanche conditions this time of year. Pay particular attention to rapidly rising temperatures or extended periods of direct sun exposure.

 


BOTTOM LINE

For today the avalanche hazard is LOW below 5500 feet. This means that human triggered and natural avalanches are unlikely, however normal caution and safe travel practices should still be exercised.  Terrain above 5500 feet is rated as MODERATE, human triggered avalanches are possible, particularly on slopes steeper than 35 degrees that have a shallow snowpack. 

 

Moderate_2

Low 


Note: 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/skiing 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.

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.


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

Avalanche Advisory – 3/30/2014

THIS ADVISORY HAS EXPIRED.

Issued: March 30, 2014 at 7:00 a.m.
Valid Until: 11:59 p.m. of issue date 

Good morning! This is Todd Hannan with the Flathead Avalanche Center avalanche advisory for Sunday, March 30, 2014. This advisory applies only to backcountry areas outside established ski area boundaries. The next scheduled advisory will be Wednesday, April 2, 2014.


MOUNTAIN WEATHER

WeatherGraphicIn the past 24 hours we received between .2 -.7 inches of snow water equivalent, most of which came in early yesterday. Mild temperatures and the heavy nature of the snow caused rapid settlement and snow totals measure a modest 1-2 inches according to SNOTEL sites. Ridge top winds were 15-35 mph yesterday with gusts to 54 mph out of the southwest. Currently, remote weather stations and SNOTEL sites are reading 23 to 30 °F with winds out of the southwest at 5-15 mph. Today will see partly to mostly cloudy skies this morning clearing mid-day with temperatures from upper 20s to mid-30s. Light snow showers should resume this afternoon intensifying in the evening and winds will be 5-15 mph out of the southwest.

 


RECENT OBSERVATIONS

RecentObservationsGraphic

The rain was coming down yesterday morning while driving down the Middle Fork corridor, after motivating to leave the dry truck we traveled up Little Shields in the Lewis Range. The rain transitioned to snow at 5400 feet. On our ascent we found sensitive storm snow, particularly near the snow line that was slightly upside down, loose, wet avalanches were easy to trigger up to about 6000 feet. Winds were strong on the ridgelines, rapidly transporting the recent snow on to leeward slopes(photo). We did not observe any natural avalanche activity yesterday, but given the short amount of time the wind took to fill in ski tracks and our snow pit, it is possible that the evidence of any avalanche activity was quickly covered (photo). Though we did experience some cracking of the wind slabs while traveling along the ridge and on low angle slopes, they did not seem to be quite as reactive as what Erich encountered in the Swan Range on Friday. While approaching a wind loaded slope, he triggered a wind slab that was up to 20 inches deep and 200 feet wide (photo). A snow profile on a north aspect revealed a 4 inch wind slab on the surface that failed with easy force but did not propagate a fracture. We also found a 35 cm slab of recently wind drifted snow on top of an older snow surface that did propagate a fracture across an extend column with moderate force (profile, photo). On our descent we traveled very conservatively expecting to pass through the mid elevation band of unstable storm snow, but found that the upside layer that we traveled through on the way up had already settled and was not nearly as reactive as earlier in the day. Below 5000 feet shallow, loose, wet snow on top of a melt freeze crust was easy to trigger on steep slopes, but also easy to manage by staying above the moving snow and avoiding terrain traps.

Glide cracks are beginning to rear their ugly heads again this spring. Erich noted a couple of glide cracks on Friday in the Swan Range (photo), and Glacier National Park rangers noted a few in the park this past week.

We received no other observations within the past 48 hours from any other locations.

 

Ski track filling in minutes by wind drifted snow. Lewis Range 3/29/2014

Ski track filling in minutes by wind drifted snow. Lewis Range 3/29/2014

Shallow wind slab on the surface. ECTP on older wind slab. Lewis Range. 3/29/2014

Shallow wind slab on the surface. ECTP on older wind slab. Lewis Range. 3/29/2014

Cross loaded terrain features in the distance. From Little Shields, Lewis Range. 3/29/2014

Cross loaded terrain features in the distance. From Little Shields, Lewis Range. 3/29/2014

Skier triggered wind slab on a wind loaded slope in the Swan Range. Depth: 12-20 inches. Width: 200 ft. Vertical fall: 300-400 feet. 3/28/2014.

Skier triggered wind slab on a wind loaded slope in the Swan Range. Depth: 12-20 inches. Width: 200 ft. Vertical fall: 300-400 feet. 3/28/2014.

 

 

 

 

 

 

 

 

 

 

 


SNOWPACK DISCUSSION

Avalanche Problem #1

Wind SlabModerate to strong ridge top winds over the past several days created wind slabs that remain a concern today. Mild temperatures will help correct this problem faster but its best to let these slabs rest a while longer while they continue to adjust. In addition to drifting snow along the ridges yesterday, we also observed many cross loaded terrain features at mid-elevations on adjacent peaks. Continue to avoid wind loaded terrain and stick to lower angled slopes, especially when travelling in alpine areas. Large cornices exist and with warming temperatures this time of year they can become particularly sensitive. Longer days with even short periods of more intense sun can make them unstable. Give cornices a wide berth when travelling around them and avoid travel below them.


 

Avalanche Problem #2

WetAval Rain and mild temperatures yesterday made it easy to trigger shallow, loose, wet sluffs in recent snow on top of a melt-freeze crust at low to mid-elevations. Today, direct sun could increase the wet avalanche hazard on recent snow in elevations that remained cool yesterday. Wet, loose avalanches can start as small point releases, but are able to entrain recent storm snow and present a slow moving but increasing hazard particularly near terrain traps. Consider moving to a more shaded aspect if temperatures rapidly rise and sun begins to melt the snow surface.

 


Avalanche Problem #3

Deep Slab Deep slabs are still a problem given the weak snow found in shallow areas (video) as well as the rain crust from early March. Though these layers are deeply buried and difficult to trigger the possibility of an avalanche breaking on these layers still exists. The recent load placed on the snowpack combined with a human trigger in the right spot may be the tipping point for a deep slab. The best place to trigger an avalanche on these layers is shallow, rocky areas so avoid this type of terrain. While the chances of triggering a slide on these layers may be low the consequences are high. Given the uncertainty of these deep slabs, it is best to avoid slopes where these layers exist or just avoid steep slopes altogether.


BOTTOM LINE

Overall, the avalanche hazard is MODERATE. This means that human triggered avalanches are possible, particularly on steep slopes with lingering storm snow instabilities and on aspects exposed to direct sun. Wind loaded slopes steeper than 35 degrees above 6000 feet are rated as CONSIDERABLE, human triggered avalanches are likely in these areas and cautious route finding is essential.  

 

Moderate_2  

Considerable

 


Note: 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/skiing 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.

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.


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 – 3/26/2014 – Skookoleel Peak area, Whitefish Range

Observer: Steven Zwisler

Date: 3/26/14

Time: 1100-1430

Location: Tributary stream to Lakalaho/Shady Grove

Activity: Skiing

 

 

Snowpack Observations:

 

Skied the drainage NE and next to Lakalaho Cr off the 6,600 ft ridge, then climbed up Lakalaho Cr and went down Shady Grove. Very good old snow on North aspects, everything else was sun affected. There were a variety of crusts and mush. We saw spot slides and a variety of pastries on south facing aspects. There were some volunteer tree bomb drops which, given their size, are worth watching for. We skied some steep roll overs and side hills without consequence. No slumping, cracking, and settling was observed or heard.

Observation – 3/26/2014 – Marion Lake, Flathead Range

 

FLATHEAD AVALANCHE CENTER

Observer Information

 

Date: 3/26/2014

Time:11:00am

Name: Gary Ludwig  Matt Hebert  Jeremy Morrone Lindsay Fansler

 

DAILY FIELD WEATHER SUMMARY

 

ZONE: Marion Lake

MT RANGE: Middle Fork

ELEV. RANGE: 4100-6800

 

SKY

PRECIP

Type/Rate

Temperature

RIDGETOP WIND (mph) (actual or est)

HN24  est @ Elev.

HS est @ Elev.

Trailbreaking/Riding Conditons

Skiing/Riding Quality

AM

PM

AM

PM

Hi

Low

Speed

Dir

0

?

Easy up to Marion Lake, more difficult above due to deep snow

Excellent! Deep and light up high.  More dense and surfy down low

 

 

Scattered snow squalls

 

40f

28f

0-10

SW

                               

 

Weather Comments

q  SKY: Mostly cloudy, a bit of sun at times

 

q  PRECIP: Occasional light snow showers

 

q  WIND: SW, varied from calm to 5-10 mph in snow squalls

 

SNOWPACK AND AVALANCHE FACTORS

q  SNOW SURFACE: Sun crust up to Marion Lake, soft  above the lake

 

q  LAYERS OF CONCERN? Early March rain crust, but it was buried about 4 feet down.  Otherwise no movement was observed; no glide cracks, wumping or surface sloughing.

 

q  RECENT AVALANCHE ACTIVITY/OBSERVATIONS  On the way up to Marion Lake we crossed several south facing chutes that had run  during the latest warm-up.

 

q  STABILITY TEST?   Yes @ elevation 6500’ north face Essex Mtn above Marion Lake.     ECTN13Q2@30cm

 

q  COMMENTS: No recent skin tracks were evident on the way up, so either no one has been up there in quite a while (seems unlikely) or there was enough new snow and wind since Saturday to erase all evidence. A light sun crust was present up to the lake, but this crust was not evident on the way down due to warming temperatures.  On the hike up to Essex ridge we encountered heavier snow on the lower half of the ascent, and increasingly lighter snow on the upper half as expected. This lighter snow led to some great face shots and “cold smoke” turns. The snowpack is as deep as I’ve ever seen it up there, with no evidence of the dreaded alders.

 

 

 

 

 

 

 

 

 

 

 

 

 

Avalanche Observations        None

NUM

SIZE

LOC

TRIGGER

 

TYPE

INC

ASP

ELEV

COMMENTS:

(Est. Depth, Width, Failure Layer, Timing)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Avalanche Advisory – 3/26/2014

THIS ADVISORY HAS EXPIRED.

Issued: March 26, 2014 at 7:00 a.m.
Valid Until: 11:59 p.m. of issue date

Good morning! This is Todd Hannan with the Flathead Avalanche Center avalanche advisory for Wednesday, March 26, 2014. This advisory applies only to backcountry areas outside established ski area boundaries. The next scheduled advisory will be Saturday, March 29, 2014.


MOUNTAIN WEATHER

WeatherGraphicOver the past 48 hours a ridge of high pressure over the region has maintained dry conditions with warm daytime temperatures and light winds. Yesterday, several mountain locations had temperatures in the 50s, Flattop Mountain SNOTEL recorded a high temperature of 52°F. Overnight temperatures were slow to dip back below freezing and a few areas near the divide picked up a small amount of snow last night (up to 2 inches). Currently, remote weather stations and SNOTEL sites are reading 25 to 33 °F with winds out of the southwest at 5-10 mph and gusts to 20 mph. Today light snow showers should continue in the area with gradually lowering snow levels and winds will be 5-15 mph out of the southwest. Showery conditions look to persist through Friday with precipitation becoming more steady Friday afternoon.

 


RECENT OBSERVATIONS

RecentObservationsGraphicYesterday was a beautiful day to ride into Kimmerly Basin in the Whitefish Range. We skied out Skookoleel Ridge in the morning and found unconsolidated surface snow on shaded aspects and a supportable melt-freeze crust on sunny aspects. It did not take long for the sun to penetrate the crust formed in the previous night, by noon our skis began to sink into the snow surface on sunny slopes. We dug snow pits on south, west, and north aspects (profiles). Our most concerning find was on a south aspect in an area of relatively shallow snow (205cm). The snow on the ground was weak and faceted and our entire column failed upon isolation (ECTPV). The good news is that the weak snow near the ground in this area was bridged by a nearly 20 cm(8 inch) thick melt-freeze crust making it difficult to trigger. Though, this still serves as a reminder that these instabilities continue to exist in our snowpack and ARE buried shallower in some areas with less force required to trigger an avalanche (Photo 1,2). On shaded aspects we observed small surface hoar developing and weak snow near the surface that could become a future issue with new snow on top.  While riding out of Kimmerly Basin in the afternoon we observed relatively small loose, wet avalanche activity on sun exposed slopes (photo).

BNSF avalanche safety was in the John F Stevens Canyon yesterday and found several layers of concern that were deeper in the snowpack, stability testing produced variable results on these layers (observation).

On Sunday skiers on Peak 6996 in the John F Stevens Canyon found a small layer of weak snow 70 cm from the surface that failed in compression tests with hard force(observation).

 

Large grained depth hoar found near the ground. Skookoleel Creek, Whitefish Range. 3/25/2014

Large grained depth hoar found near the ground. Skookoleel Creek, Whitefish Range. 3/25/2014


Entire column failure upon isolating the back of the column. Skookoleel Creek, Whitefish Range. 3/25/2014

Entire column failure upon isolating the back of the column. Skookoleel Creek, Whitefish Range. 3/25/2014


Loose, wet avalanche in Kimmerly Basin. Whitefish Range 3/25/2014

Loose, wet avalanche in Kimmerly Basin. Whitefish Range 3/25/2014


Loose, wet avalanche in Kimmerly Basin. Whitefish Range 3/25/2014

Loose, wet avalanche in Kimmerly Basin. Whitefish Range 3/25/2014

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 


SNOWPACK DISCUSSION

Avalanche Problem #1

Deep SlabThough deeply buried and difficult to trigger, the late January/early February crust/facet layer in addition to weak, faceted snow near the ground still lurks in the snowpack. The best place to trigger an avalanche on these layers is shallow, rocky areas so avoid this type of terrain. The rain event that provided the trigger for that large avalanche cycle in early March formed a thick rain crust that now sits about 2-3 feet from the surface. This layer has shown instability in some areas with recent stability tests. The chances of triggering an avalanche on these layers may be low, but the consequences are high. It remains important to do site specific evaluation of persistent slab in the areas you are travelling and remember that tracks (even lots of tracks) do not mean stability. Given the uncertainty of these deep slabs, it is best to avoid slopes where these layers exist or just avoid steep slopes altogether. Additionally, large cornices tower over many slopes in the area and their strength will be tested through the spring with increasing direct sun and warming temperatures. The large amount of force exerted by a falling cornice can trigger these deep instabilities. It will become increasingly important to be aware of cornices when travelling in the backcountry. As usual, give them a wide margin when above them and avoid areas below them.

 


 

Spring can bring a mixed bag of weather and snow conditions. Mountain temperatures remain near the freezing mark this morning and a small amount of precipitation is in the forecast. It is important to pay attention to rapidly changing conditions as weather can greatly affect snow and avalanche conditions this time of year. Pay particular attention to rain falling on the snow if temperatures climb higher than expected.

 


BOTTOM LINE

For today, the overall avalanche hazard is MODERATE. This means that human triggered avalanches are possible, particularly on steep slopes and areas of shallow snow where deeper instabilities exist in the snowpack. It remains important to evaluate snowpack and terrain carefully in the specific areas that you are travelling in.

Moderate_2

 


Note: 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/skiing 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.

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.


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 – 3/25/2014 – John F Stevens Canyon, Glacier National Park, Lewis Range

 

BNSF RAILWAY AVALANCHE SAFETY

VOLUNTARY FIELD OBSERVATIONS

(406) 863-0476 Email: richard.steiner@bnsf.com

 

 

 

 
 

DATE

SUBMITTED:

TIME SUBMITTED:

OBSERVATION LOCATION

OBSERVATION

DATE:

SUBMITTED BY:

3/26/2014

        0630

Shed 7 West SZ

3/25/2014

Steiner

GENERAL INFORMATION:

Ascended the Shed 7 avalanche path to the Shed 7 West path.  Followed the main path to approximately 5400 feet (1636 m) elevation and then exited path to the Shed 7 West/ Shed 8 ridgeline.  Followed ridgeline to 6020 feet (1824 m) elevation and completed a full profile on a east- northeast aspect.  Conditions for skin ascent were good and due daytime warming, descent conditions were poor.  No snowpack collapsing, audible failures or shooting cracks observed.

WEATHER OBSERVATIONS:

Mostly clear to clear skies with air temperatures in the morning around 200F.  Throughout the daytime hours air temperatures climbed to near 500F at all elevations, winds were calm to light from the SW, visibility unlimited, and conditions remained dry.

 

SNOWPACK OBSERVATIONS:

 

Conducted a full profile on a 35 degree East/ Northeast aspect at 6200 feet elevation located in a looker’s right path of the Shed 7 West starting zone.  Snowpack depth was 377 cm (9 feet).

 

  • A significant temperature gradient existed in a portion of the snowpack between the interfaces of 270 cm from the ground and the snowpack above this height and 220 cm from the ground and the snowpack below this height.  In this 270 cm to 220 cm portion of the snow pack the snowpack temperature was recording -1 to -20C. Interface snowpack temperatures and temperatures at all other elevations in the snowpack were recording 00C.

 

  • Snowpack was moist throughout.

 

  • A deep seated layer of concern at this profile location was a 1F mixed form layer sandwiched between two pencil hard crusts located 157 cm from the ground surface or 120 cm from the snowpack surface.

 

  • Extended Column stability tests conducted on this deep layer of greatest concern resulted in “No Results” when conducted from the surface of the snowpack or in deep tap tests.  Compression tests, however, resulted in conclusive results on this layer at CTH 22 and CTH 23 Q2.

 

  • A more surface related layer of concern in this profile location was located 37 cm from the snowpack surface and was related to a mixed form layer beneath a 4F hard crust.  Again No ECT results on this layer but Compression Tests conclusively scored CTM 18 and CTM 16 Q2.

 

 

 

AVALANCHE OBSERVATIONS:

 

  • No recent avalanche activity observed.

 

 03_25_14_Shed 7 west

 

 

 

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.