Good Morning. This is Mark Staples with the Gallatin National Forest Avalanche Advisory issued on Friday, March 14 at 7:30 a.m. Alpine Orthopedics and Buck Products sponsor today’s advisory. This advisory does not apply to operating ski areas.
Tuesday, March 11, Cooke City Avalanche Fatality
On Tuesday an 18 year old male snowmobiler from Minnesota died in an avalanche on the northwest face of Crown Butte outside Cooke City. The victim was stopped on the slope while two others were riding when the avalanche was triggered. Neither he, nor anyone in his party of seven, was wearing a beacon. Cooke City Search and Rescue located him with a probe pole under six feet of debris near the toe of the avalanche about 2+ hours later. Our sincerest sympathies go out to the family and friends of the victim.
Five pictures on our photos page.
Video on the accident and one on the snowpack.
A full report will be issued in the coming days.
This morning mountain temperatures were in the low 20s F. Winds were blowing from the SW at 10-15 mph gusting to 20 mph. A storm over western Washington this morning will bring clouds this afternoon and more snow tonight. High temperatures today should reach the mid 30s F and winds should blow 10-15 mph from the SW. 2-4 inches of snow should fall by tomorrow morning.
Bridger Range Gallatin Range Madison Range
Lionhead area near West Yellowstone Cooke City
Now is a tough time because the odds of triggering an avalanche decrease a little each day following Monday night’s heavy snowfall. Unfortunately the consequences remain severe because avalanches have been breaking near the ground or in the middle of the snowpack. Most precipitation fell in the Bridger Range where many natural avalanches broke over huge areas. Scroll through all the recent avalanche photos. A little less precipitation fell in the Southern Madison Range, and yesterday where my partner and I didn’t spot any large natural avalanches, but we found very weak facets near the ground on a SE facing slope (photo of layers).
Because these weak layers are buried deeply in the snowpack, triggering an avalanche on them has become harder to do. It requires hitting a trigger point on a slope. There are two problems. 1) We don’t know where these trigger points exist. 2) Some slopes may have many trigger points while others may only have one and others may have none at all. Ski or snowmobile tracks on a slope are not meaningful information. Those riders either found a stable slope OR they didn’t hit the trigger point. It’s very hard to know the difference. The only good news is that no recent avalanches have been triggered from flat ground below steep slopes. This means you have to ride onto a steep slope to trigger a slide.
Will warm weather improve stability? Unfortunately not. Large facets near the ground are here to stay. The only thing that matters is time. After each day without snow, the odds of triggering an avalanche decrease while every time it snows the odds go back up. With a lot of snow (or rain) they go up dramatically. With a few inches of snow they go up just a little.
Because the consequences of triggering an avalanche remain severe, the avalanche danger is rated CONSIDERABLE on slopes steeper than 35 degrees. Less steep slopes have a MODERATE avalanche danger.
CORNICES
Yesterday, two people received minor injuries (luckily) and were rescued and when a cornice broke underneath them and they tumbled about 1200 feet down slope. They were walking along the ridge north of Bridger Bowl and outside the ski area. Cornices are large now and creep during warm weather. They are unpredictable, deadly, and often break further back than you would expect. Give these monsters a wide berth.
Mt. Jefferson Avalanche: Video
This is not in our forecast area, but it has a similar snowpack and avalanche concern.
On Wednesday, March 12, one rider in a group of seven in the Centennial Range between Mt Jefferson and Sawtell Peak triggered a deep slab avalanche. They were all wearing beacons and airbags and climbing one at a time. He stayed on his sled, pulled his airbag and was able to remain on his sled through the avalanche. No injuries. Photo1 and photo2.
I will issue the next advisory tomorrow morning at 7:30 a.m. If you have any snowpack or avalanche observations drop us a line at mtavalanche@gmail.com or call us at 587-6984.