Good Morning. This is Alex Marienthal with the Gallatin National Forest Avalanche Advisory issued on Monday, January 22nd at 7:00 a.m. Today’s advisory is dedicated to Andrew Greicar who was killed in an avalanche outside of Cooke City on this day fifteen years ago. The Avalanche Center has been granted an “exception” and will remain open at full capacity during the government shutdown. This advisory does not apply to operating ski areas.
AVALANCHE FATALITY
Saturday afternoon a snowmobiler was caught, buried and killed in an avalanche south of Reas Peak on the Caribou-Targhee National Forest near Island Park, Idaho. The rider was located by his group, with a beacon and buried deeply. We will post more information as it becomes available.
The mountains do not have any new snow this morning, temperatures are single digits to teens F, and wind is southwest at 15-25 mph with gusts of 30-40 mph. Near Cooke City and West Yellowstone wind is 5-15 mph with gusts to 20 mph. Today, wind will be west-southwest at 20-30 mph with temperatures in the teens to low 20s F. Light snow is expected through today with 2-3” likely by morning.
The Lionhead area near West Yellowstone has an unstable snowpack and dangerous avalanche conditions. It is possible to trigger avalanches 2-4’ deep across entire slopes. A weak layer of facets 1-2’ above the ground has shown clear signs of instability for three weeks. There have been snowmobile triggered avalanches and large collapses almost daily (photo, photo), and three people killed in avalanches nearby since the start of 2018.
Saturday, I was on Lionhead Ridge and found stable results in stability tests, then collapsed the entire surrounding low angle slope as we left our snowpit (video). Signs of instability are slowly becoming less obvious, and these large avalanches will get harder to trigger. The first person on a slope may not trigger a slide, while a large, deadly avalanche could be triggered by the second, third, or 30th person. Avoid steep slopes and terrain below. Avalanche danger is CONSIDERABLE on all slopes.
In the Bridger, Gallatin, and Madison Ranges strong wind overnight drifted recent snow into slabs 1-3’ deep. These slabs are easy to trigger, and likely found near ridgelines and the edges of cliffs and gullies (photo, photo). On Saturday, a skier triggered and was carried hundreds of feet in a wind slab on Naya Nuki peak in the Bridger Range. Yesterday on the Throne, a skier triggered and was caught in a wind slab (photo), and other skiers reported easily triggering a 2-3’ deep, 50’ wide slab. Near Cooke City, wind overnight remained light, but fresh slabs are possible if wind increases today. Yesterday a rider saw a recent natural avalanche on the wind loaded, east face of Mt. Abundance (photo). Avoid recently wind loaded slopes today and assess the terrain for consequences of even small slides.
Snow on Friday buried a weak layer of surface hoar (photo), and in some places near surface facets. We have found these layers to be unreactive in stability tests and show no signs of instability at Mt. Ellis, Hyalite, Lionhead, and Taylor Fork. However, uncertainty exists and these layers are assumed guilty until proven innocent. Dig 1-2’ to rule out these weak layers before riding any steep slope (photo).
Avalanches breaking on facets 2-4’ deep are becoming less likely, but are possible and could be large. This weak layer is most unstable and likely to trigger where the snowpack is 3-5’ deep or less. Doug found unstable test results on this layer at Taylor Fork yesterday (video), and Eric found similar in the northern Madison Range last week (video). Be cautious of steep slopes where the snowpack is relatively shallow or highly variable.
Today, avalanche danger is CONSIDERABLE on wind loaded slopes and MODERATE on all other slopes.
If you get out and have any avalanche or snowpack observations to share, drop a line via our website, email (mtavalanche@gmail.com), phone (406-587-6984), or Instagram (#gnfacobs).
King and Queen of the Ridge
King and Queen of the Ridge, Saturday, February 3rd. A Hike and Ski/Ride-a-Thon fundraising event to support the Friends of the Gallatin National Forest Avalanche Center. Sign up and start collecting pledges HERE.
Upcoming Avalanche Education and Events
BOZEMAN
TONIGHT!!!, MAP Brewing Pint Night, 4-8 p.m. MAP donates 50 cents of every pint sold to the Friends of the Avalanche Center.
Jan. 24, 25 and 27, Advanced Avalanche Workshop w. Field Day, Info and Register Here
Feb. 6th, Sidecountry specific avalanche awareness for family and friends. 6-8 p.m. @ Beal Park
Feb. 7th, Woman’s specific avalanche awareness, 6-7:30 p.m. @ REI in Bozeman
Feb. 7th, Avalanche awareness, 6-7:00 p.m. @ Roski Hall MSU
Feb. 9 and 10, Companion Rescue Clinic, Info and Register
March 2nd, Avalanche Awareness, 6-7:00 p.m. Bozeman Split Fest
March 7th, Avalanche Awareness, 6-7:30 p.m. @ REI
Dillion
Feb. 24th and 25th, Snowmobile intro to avalanches w/ field course. More info: https://msuextension.org/conference/.
WEST YELLOWSTONE
Feb. 3rd, Avalanche Awareness, 7-8 p.m. at West Yellowstone Holiday Inn Conference Center
COOKE CITY
Every Friday and Saturday, Current Conditions Update and Avalanche Rescue, Friday 6:30-7:30 p.m. at The Antler's Lodge in January. Saturday anytime between 10-2 @ Round Lake.
Three snowmobilers have been killed in the last three weeks near West Yellowstone and Island Park. Our report from the snowmobiler avalanche fatality on January 10 is HERE.