On December 31, 2022 a snowmobiler was killed in a very large avalanche north of Cooke City, MT. The avalanche occurred near Daisy Pass on Crown Butte on a southeast facing slope at 9,800’. The avalanche appeared to be 2-4' deep, 500' wide, 600' vertical, and broke on weak snow near the bottom of the snowpack. Photo: GNFAC
22-23
On December 31, 2022 a snowmobiler was killed in a very large avalanche north of Cooke City, MT. The avalanche occurred near Daisy Pass on Crown Butte on a southeast facing slope at 9,800’. The avalanche appeared to be 2-4' deep, 500' wide, 600' vertical, and broke on weak snow near the bottom of the snowpack. Photo: GNFAC
Forecast link: GNFAC Avalanche Forecast for Sun Jan 1, 2023
Snowmobiler triggered hard slab avalanche Sheep Mtn.
...we rode over the saddle between Sheep and Scotch Bonnet and saw an avalanche that appeared very recent, and likely triggered by a snowmobiler. It was on a west facing slope at 10,000', and was a hard slab 1-4 feet deep and 150' wide, ran about 200' vertical. AMu-HS-R3-D2-O. This was a clear sign that weak layers exist, especially where the snowpack is relatively shallower, and recent snow has been drifted into thick slabs that are unstable over this weak snow.
Snowmobiler avalanche fatality on Crown Butte
On December 31, 2022 a snowmobiler was killed in a very large avalanche north of Cooke City, MT. The avalanche occurred near Daisy Pass on Crown Butte on a southeast facing slope at 9,800’. Two brothers (age 17 and 21) from Washington were snowmobiling uphill on adjacent slopes. The older brother was climbing a steeper slope and triggered the avalanche 100-200’ below the top. He was carried 600 vertical feet and buried 5 feet deep. The buried rider was wearing an airbag pack that was not deployed. Both riders had shovels and probes. They were not wearing avalanche beacons. A nearby group of riders rode up to the slide within minutes after it happened, saw a buried snowmobile and began to search for the rider. One rider from that group went into Cooke City to alert Search and Rescue. The buried rider was located with a probe line an hour after the avalanche happened. He was unable to be revived with CPR and AED at the site. Our deepest condolences go out to the family, friends, and those involved.
The avalanche appeared to be 2-4' deep, 500' wide, 600' vertical, and broke on weak snow near the bottom of the snowpack. AMu-HS-R3/4-D3-O
Snowmobiler triggered avalanche Sheep Mtn.
Yesterday afternoon (12/30) we rode to Henderson Bench and dug a pit at 9,600' on a NE facing slope. HS was 188cm and we had ECTN22 and ECTN23 at 146 cm above the ground. New snow from the last week was over a foot deep and it was snowing steadily, an inch an hour at times while we were out. Snowfall tapered off in the evening, then this morning dropped 4" in town and more in the mountains.
Today we were rode north of Cooke City. We rode over Lulu Pass and dug a pit at Goose Creek at 9,500' elevation on a NE facing slope. HS was 216 cm with 40cm of new snow from the last couple days. The top 14" of the new snow weighed 0.7" snow water equivalent. We got ECTN 25 and ECTN 27 at 150cm above ground on facets sized 0.5-1mm.
Later we rode over the saddle between Sheep and Scotch Bonnet and saw an avalanche that appeared very recent, and likely triggered by a snowmobiler. It was on a west facing slope at 10,000', and was a hard slab 1-4 feet deep and 150' wide, ran about 200' vertical. AMu-HS-R3-D2-O. This was a clear sign that weak layers exist, especially where the snowpack is relatively shallower, and recent snow has been drifted into thick slabs that are unstable over this weak snow.
Whumpf, propagating test result
skied both NE, S and SW aspect lines in Sheep Creek Basin. No signs of wind loading where we traveled, up to 9600’ at the saddle between Sunset and Miller Mountain. There were light winds (M gusts). 8-10” of new low density snow.
Dug a pit on a SW aspect, 8480’:
160cm deep
CT22Q2 Down 40, EctN 25 down 40
ECTP28 down 85
Pole probing confirmed the presence of the top persistent grain layer throughout the landscape, although the associated crust was not widespread.
We also experienced a Whumpf at 45.03667, -109.96733 On a SW slope, 9000’ in a shallow area (125cm depth).
Cracking and Collapsing - Cabing Creek Divide
From observation: "Snow above collapsed into the trench from my sled, looked to have broken on a weak layer about 1.5’ down."
Snow above collapsed into the trench from my sled, looked to have broken on a weak layer about 1.5’ down.
Crack/collapse cabin creek divide
Snow above collapsed into the trench from my sled, looked to have broken on a weak layer about 1.5’ down.