Good Morning. This is Doug Chabot with the Gallatin National Forest Avalanche Advisory issued on Thursday, January 12th at 7:00 a.m. Today’s advisory is sponsored by Cooke City Super 8/Bearclaw Bob’s and Gallatin Valley Snowmobile Assoc. This advisory does not apply to operating ski areas.
In the last 24 hours the mountains have picked up more snow. Around Bozeman 2-3” fell last night; the mountains from Big Sky to West Yellowstone got 2-4” last night on top of the 8-12” from the previous night, and in Cooke City 3” fell on top of the 2’ measured yesterday morning. The storm is over, winds are west at 10-15 mph with gusts of 30 and temperatures in the single digits to low teens. Today will become clear, winds will be light and temperatures will reach the high teens.
Cooke City
The avalanche warning has expired with the snowstorm. Since Sunday night the mountains got 4’ of snow (3.5” of SWE) with strong winds that blew at all elevations. Avalanches released naturally on a thin layer of facets underneath the new snow. I was in Cooke City and made a video showing this layer breaking in my tests. Yesterday morning I awoke to 2’ of new snow. My partner and I pinned our throttles and plowed up Miller and Fisher drainages where avalanches released in the night, many barely visible from all the fresh snow. I made another video of avalanches near Lulu Pass (photos). All the slides looked like they broke at the new/old snow interface. There is another weak layer at the ground, but I have no evidence that avalanches released on it.
Avalanches are likely today, especially from skiers or snowmobilers that venture onto steep slopes. Over the next few days the likelihood of triggering slides will decrease, but deadly potential will remain. For today, the avalanche danger remains HIGH on any slope steeper than 35 degrees…most open slopes around Cooke. Lower-angled terrain will have a CONSIDERABLE danger, a serious level of danger.
Madison Range Southern Gallatin Range
Lionhead area near West Yellowstone
The mountains from Big Sky to West Yellowstone have received 1-2” of SWE totaling 1-2’ of snow since Sunday. Winds blew strong out of the W-SW during this time. The snowpack is weak and unsupportable in most areas. Eric sank to the dirt when he stepped out of his skis near Hebgen Lake on Tuesday (video). The most prominent weak layer in the snowpack was formed at the surface during the subzero weather last week. Wind drifts on this layer will avalanche with the added weight of a skier or rider. For today, the avalanche danger is rated CONSIDERABLE on wind-loaded terrain and MODERATE elsewhere.
Bridger Range Northern Gallatin Range
The Bridger Range and northern Gallatin Range have gotten 10-12” of snow since Sunday with strong westerly winds. The winds did two things, they formed wind drifts and built large cornices. The drifts overlay a weak, faceted snowpack that could be triggered by skiers, riders or breaking cornices. In the Bridger Range on Tuesday skiers accidently triggered a cornice as their friends were skiing below. Luckily it missed them and did not avalanche the slope. For today, avalanches are still possible and the danger is rated MODERATE.
Eric will issue the next advisory tomorrow morning by 7:30 a.m.
We rely on your field observations. Send us an email with simple weather and snowpack information along the lines of what you might share with your friends: How much new snow? Was the skiing/riding any good? Did you see any avalanches or signs of instability? Was snow blowing at the ridgelines? If you have snowpit or test data we'll take that too, but this core info is super helpful! Email us at mtavalanche@gmail.com or leave a message at 406-587-6984.
Month of January: Montana Ale Works has chosen the Friends of the Avalanche Center as January's "Round It Up America" recipient. Every time you round-up your bill the change gets donated to the Friends. Pennies equal dollars!
King and Queen of the Ridge: A Hike and Ski/Ride-a-Thon fundraising event to support the Friends of the Gallatin National Forest Avalanche Center. Register with Bridger Bowl HERE, make pledges HERE.
BOZEMAN
Friday and Saturday, January 13 and 14, Companion Rescue Clinic, REI Friday 6 p.m., field Saturday TBA. Register here: https://events.ticketprinting.com/event/21313.
Tuesday, January 17, Avalanche Center Forecaster’s Social at Montana Ale Works. A small-plate fare and beer tasting fundraiser for the Friends: $40.00/person; 2 seatings (5:30 p.m. and 7:00 p.m). Get your tickets HERE.
COOKE CITY
Weekly rescue training and snowpack update, 6-7:30 p.m., The Antlers Lodge on Friday, field location Saturday TBA.
BIG TIMBER
Tuesday, January 17, Avalanche Awareness, 6-7:30 p.m., Sweet Grass County High School.