Wednesday, December 31, 2008

Avalanche Warning

Be careful out there, the avi danger is still very high! Here is this morning's bulletin from the GNFAC, read the part about the snowmobiles, its important to remember run out zones are dangerous, too!


The southern Gallatin Range, the southern Madison Range, the mountains near West Yellowstone and the Lionhead Area, the mountains near Cooke City, and the Washburn Range:

The southern mountains finally got a reprieve from snowfall yesterday. But things were not quiet. Skiers and snowmobilers triggered slides around Cooke City. Republic, Henderson, Fisher, Miller and Scotch Bonnet Peaks all had slab avalanches release in the last 48 hours. A snowmobiler got buried. Outside West Yellowstone the mountains had many crowns lacing the ridgelines from natural avalanche activity. The snowpack is extremely sensitive and you’ll find avalanches again today.

Yesterday, three snowmobilers were sitting on the flats below the south face of Crown Butte outside Cooke City. They had their sleds turned off when another rider on an adjacent hill unknowingly triggered the slope above them. They fired up their machines and full throttled out, but one rider’s snowmobile took one pull too many and he lost the race with the avalanche. He was tumbled for 100 yards. He was wearing an ABS airbag pack as well as a beacon. When he pulled the handle of the ABS it broke off in his hand without deploying! As soon as the slide stopped his two partners saw the ski and skid plate of the sled sticking out of the snow, rushed over and found a glove and boot wiggling frantically. They dug him up and the buried rider was ok. Even though they were in the flats, they were exposed to the runout zone of the avalanche path above them. This close call is a reminder to be extra careful since its dangerous to even be near avalanche terrain right now. We are continuing the Avalanche Warning since avalanches are likely and a HIGH danger exists on all slopes in the southern mountains.

The Bridger, northern Madison and northern Gallatin Ranges:

The northern mountains have weak and unstable snow buried a few feet under the surface. Wind-loaded slopes in the Bridger Range avalanched in the past few days while ski patrols also triggered slides on the buried facets. Yesterday, on Lone Peak’s south face, the Big Sky Ski Patrol got good results on avalanche control in an area that’s been closed to the public. They had wind slabs up to 6 feet deep avalanche on faceted snow near the ground. A ski patroller was caught in one of these slides when the cornice broke behind him. After a long ride he emerged on top of the debris uninjured. Skiers also reported weak and unstable snow in the Hyalite drainage, Mt Ellis, Chestnut Mt in the northern Gallatins, and in Truman Gulch on the west side of the Bridgers. For today, a CONSIDERABLE avalanche danger exists on all slopes recently wind-loaded as well as slopes steeper than 35 degrees. Lower angled slopes have a MODERATE danger.


Like an After School Special, today’s advisory has some valuable lessons. Stay back from cornices; even flat terrain can be deadly; have your sled running and pointed away from steep slopes; and even if you’ve got an ABS airbag, always wear a beacon.

Ron will issue the next advisory tomorrow morning at 7:30 a.m. If you get out in the backcountry give us a call or send us an email with your observations. You can reach us at 587-6984 or at

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