Regional Conditions for Southern Gallatin

A large snowmobile triggered avalanche in the Gravelly Range (Outside of advisory area) on February 10th, 2019.

From email: "One rider was involved in the incident and was fortunate to be on the upper left side of the bowl when he saw the slide start. ... the crown was about 325 wide and varied in depth from 1 to 4 or 5 feet.  The ridge line was wind loaded and this was an issue we had discussed as a group and wanted to avoid.  We had read the reports for the day and knew that wind loading as well as a persistent week layer were both concerns. .... The rider involved entered the area from around where the road switchbacked and did not realize what was above him due to reduced visibility."

Snowmobilers in the Lionhead area got unstable test results, easily propagating fractures in ECT tests on a weak layer buried about 50 cm deep. Photo: J. Norlander

Crown of avalanche that was triggered by a group of four skiers. Two were partially buried (1 injured, 1 killed) on 1/25/19. They were all ascending and near the top of the path when the avalanche broke. The top two skiers held onto trees as the avalanche pushed by them. Photo: GNFAC

Overview of avalanche path where a group of four skiers were caught, and two were partially buried (1 injured, 1 killed) on 1/25/19. Crown is marked by black line and location of partial burial/deceased is tip of red arrow. The other partially buried skier was 200' lower. They were all ascending and near the top of the path when the avalanche broke. The top two skiers held onto trees as the avalanche pushed by them. Photo: GNFAC

"One small slide on a N asp at head of Bacon rind creek, elev 8750,  had a crisper look than most of the others observed, suspect more recent." Photo: M. Best

This graph shows snow water equivalent (SWE) by date at the primary SNOTEL sites that we use in the GNFAC region. From October 1st, 2018 to January 12th, 2019. Steeper lines indicate bigger storms and flatter lines indicate periods of little to no snow. A large storm at the beginning of Novermber laid down a 1-3 foot base. Relatively dry and cold weather through November caused much of that snow to become weak. This weak snow was buried by a series of storms. Avalanches were seen during and following many of these storms. During dry weather between storms, more weak layers formed on the surface of the snowpack and were subsequently buried. (Graph created by GNFAC from NRCS provisional data).

In Cabin Creek (1/10/19) we found a recently buried layer of surface hoar as well as the weak, sugary snow that makes up the bottom 1.5' of the snowpack in the southern ranges. Avalanches are possible to trigger on the sugary facets near the ground. Both of these weak layers will persist and cause avalanches when we get more snow and wind loading. Photo: GNFAC

February 2, King and Queen of the Ridge at Bridger Bowl (fundraiser). Register with Bridger to hike in the event, and create a pledge page to raise funds with your Ridge laps.

This was a recent snowmobile triggered avalanche In Tepee Basin, southern Madison range. This slide failed on facets near the ground and ran into a terrain trap. With more snow and wind in the forecast, it will be important to make conservative terrain selections. Photo: GNFAC 

We rode into Cabin Creek behind Sage Peak (via Taylor Fork) and found 2.5' of snow. The lower half was weak, sugary and unsupportive. The upper half was a slab of recent snow that collapsed with moderate force (ECTP 11). Our sled's tracks easily broke through 2.5' of snow to the ground, a sign of poor snowpack structure. Photo: GNFAC

Snow bikers in the northern Gallatin Range "witnessed a very reactive new snow layer in all wind loaded areas." (12/30). Photo: J. Polus

The snowpack at 9,000' above Hebgen Lake near West Yellowstone is 60-70cm (~2 feet) deep. It is mostly weak, sugary facets and will struggle to support the weight of future storms. Photo: GNFAC

A skier reported a recent slab avalanche at Ernest Miller in the southern Madison. This is a good reminder that as you move further south in our advisory area, we are seeing a thinner and generally less stable snowpack. Photo: C. Grote

A skier in the southern Gallatin found a buried layer of surface hoar that propagated in stability tests. This surface hoar layer has been found at several locations in the advisory area. Photo: S. Reinsel

A skier on Ramshorn Peak in the southern Gallatin Range got shooting cracks and observed a recent avalanche in wind loaded terrain. This is a good reminder that isolated instabilities still exist on wind loaded slopes. Photo: C. Kussmaul  

Surface hoar crystals growing on top of a thin, faceted snowpack in the Southern Gallatins. Photo: B. VandenBos

Cracking of fresh drifts was a sign that avalanches were likely on steep, wind loaded slopes on Saddle Peak. Photo: GNFAC

Snow water equivalent at SNOTEL stations in the GNFAC advisory areas for the 18-19 season to date. Weak layers formed on the surface of the snowpack during the dry weather (flat section of lines), then they were buried by the recent 10-14" of snow (steep increase at end of graph). Image: GNFAC

Climbers triggered this very small wind slab on the way to a climb up Flanders in Hyalite (11/11). A tiny slide to a skier can be bad news for a climber since losing one's balance or getting pushed off a cliff can be deadly. From an email (edited):

Photo: S. Magro

From an email:

"By and large right side up snowpack. Some small facets below the 11/1 ice crust at the ground, but well bonded snowpack overall. Pit observations consistent with hand pits dug throughout the day touring north out of Bridger Bowl." Photo: M. Zia

From an email: "ECTP 5 at the top of a chute on the south face of the Texas Meadows knob. Propagated on a layer 15cm from the top of the snowpack." Photo: J. Zimmerer

From Instagram:

"Careful out there this year! While we are lucky enough to have a mostly stable snowpack here in Southwest Montana, we did just find this little wind slab well below the ridge line in Middle Basin. Slowboarder was fine" @chartierk

A skier found 80 cm of stable snow on an east facing slope at 9200' in Beehive Basin. Winds created these newborn cornices along the ridge. Photo: T. Allen

From e-mail: "Was descending off of Zach Attack tonight and set off a small slab in the gully on the decent. This was about 100 meters below the start of pitch 1. Constant whipping winds and lots of new deposited snow likely caused the slab to form. Climber caused. Didn’t carry me as it was small. Would be wary of the mummy cooler gullies abover scepter as well."

From e-mail: "Was descending off of Zach Attack tonight and set off a small lab in the gully on the decent. This was about 100 meters below the start of pitch 1. Constant whipping winds and lots of new deposited snow likely caused the slab to form. Climber caused. Didn’t carry me as it was small. Would be wary of the mummy cooler gullies abover scepter as well."

From a tour up Miller Creek: "Good stability and structure found overall.  No collapsing nor cracking experienced, minor wind effect, and only some minor point release avalanche activity noted on the east aspect of Crown Butte." Photo: B. Fredlund

Natural wind slab that broke after 3-4 feet of new snow over 6 days. Photo: B. VandenBos

Natural avalanche activity was widespread in Hyalite on Tuesday 11/6. Obs from e-mail: "The newest snow (about 18", I'd guess past 48hrs) is touchy soft slab. The top 8 inches also exhibit a storm slab-like quality.  There appears to be a very slight density change between the two.  Top 8" fracture and propagate cracks readily on gentle terrain, whereas in steeper terrain, the deeper slab (again, about 18" down) was propagating as I was skinning up the headwall in the steep creek drainages and steeper features nearby. Lots of natural activity on steeper terrain, but vis was limited. Photo: G. Antonioli

Natural avalanche activity was widespread in Hyalite on Tuesday 11/6. Obs from e-mail: "The newest snow (about 18", I'd guess past 48hrs) is touchy soft slab. The top 8 inches also exhibit a storm slab-like quality.  There appears to be a very slight density change between the two.  Top 8" fracture and propagate cracks readily on gentle terrain, whereas in steeper terrain, the deeper slab (again, about 18" down) was propagating as I was skinning up the headwall in the steep creek drainages and steeper features nearby. Lots of natural activity on steeper terrain, but vis was limited. Photo: G. Antonioli

From the MSU Backcountry Club Instagram page:

Warning! This is a current, fresh, crown in the northern Bridgers! Every aspect had a visible crown and avi debris! This crown was 56cm at it deepest and over 8 meters long. ECTP21@53 and CT24@54 on the overlying slab. Photo: @msubackcountryclub More Details.

This avalanche was observed on the morning of Friday 11/2. It broke from a natural trigger in the Big Couloir at Big Sky Resort. New snow fell and was drifted into slabs overlying older, hard layers of snow from October. The resort is not open and no people were in the area of the avalanche at that time. Photo: Big Sky Resort More details

POWDER BLAST
26 October 2018

BUY TICKETS HERE

Join us for the best fundraiser of the year! All proceeds benefit the Friends of the Avalanche Center which supports avalanche awareness, education and information throughout southwest Montana.

Your $35 donation gets you an unforgettable evening at the Emerson Cultural Center.

Grizzly Outfitters of Big Sky is title sponsor of this year's 20th Annual Powder Blast. Mystery Ranch, World Boards, Community Food Co-op, Highline Partners and Spark R&D are key sponsors along with Alpine Orthopedics, Stronghold Fabrication, Werner Wealth Management, Scott Lawson Dentistry, and Knoff Group Real Estate. Additional support comes from Javaman, Edward Jones, Massive Design, Bountiful Table and Katabatic Brewing. 

Beer from Katabatic Brewery and Wine from Montana Ale Works

Dinner by Bountiful Table

Music by Laney Lou and the Bird Dogs and the best silent auction of outdoor gear in the valley!

Wet slab avalanche in the Centennial range. Multiple days without freezing created widespread wet slides last week (5/6-5/11). Photo: @waxeman

Wet slab avalanche in the Centennial range. Multiple days without freezing created widespread wet slides last week (5/6-5/11). Photo: @waxeman

Wet slide carnage observed off of Skyline Ridge near Cabin Creek May 11/12. Many days of above freezing temperatures created widespread wet slide activity over the previous week. Photo: B. Lukens

Wet slide carnage observed off of Skyline Ridge near Cabin Creek May 11/12. Many days of above freezing temperatures created widespread wet slide activity over the previous week. Photo: B. Lukens

Massive cornices create a few hazards as they warm and weaken under the spring heat. They become easier to trigger, can break naturally, and form dangerous, deep cracks along ridgelines. From e-mail: "The crack was up to 30' deep, and had pulled large pieces of vegetation from the ridgeline it used to be attached to." Photo: S. Reinsel