Good morning. This is Doug Chabot with the Gallatin National Forest Avalanche Advisory issued on Tuesday, February 12 at 7:30 a.m. Cooke City Motorsports and Yamaha sponsors today’s advisory. This advisory does not apply to operating ski areas.
Last night a trace to one inch of snow fell in the southern mountains. Currently, westerly winds are blowing 10-20 mph except in the Bridger Range and Hyalite where they are reading 30-40 mph. Temperatures are near 10F under partly cloudy skies. Today will be partly to mostly cloudy with winds increasing out of the west to northwest. A trace to one inch may fall later tonight.
Bridger Range Northern Gallatin Range
Strong winds in the Bridger and northern Gallatin Ranges are scouring some slopes and loading others. The Hyalite area has a foot of snow that fell early Sunday morning which is now blowing around. On Saturday evening skiers triggered an avalanche on Alex Lowe Peak, located southwest of Mt. Blackmore. The snowpack was thin, weak and capped with a dense wind slab. The price they paid was only a lost ski and a cold bivouac. Separately, avalanches can be expected where the snowpack is thin and also on wind-loaded slopes, but combined these create especially worrisome conditions. Although the Bridger Range did not get the snow that Hyalite did, their downhill winds are especially strong and scouring the alpine regions while loading slopes and gullies at mid-elevations. Today the avalanche danger is rated CONSIDERABLE on all wind-loaded terrain. All other slopes have a MODERATE danger.
Madison Range Southern Gallatin Range Lionhead area near West Yellowstone
Without new snow or wind-loading the avalanche danger from Big Sky to West Yellowstone is slowly improving, but getting trickier to assess. There are two problems buried in the snow. The first problem is on slopes with a thinner snowpack (about three feet thick or less) where 2/3 of it is facets. Eric and I toured in Beehive Basin yesterday and confirmed this. Other skiers around Big Sky on Sunday and Monday also got collapsing and cracking and triggered a small pocket on a thin, west facing slope (photo). Yesterday on Lionhead Ridge outside of West Yellowstone skiers triggered a thinly covered slope that had a wind-slab on it (photo). Many slopes do not have these instabilities and will not crack or “whumph”. In the absence of obvious warning signs, the first line of defense should be a quick probe to feel for a thin snow depth—thin is bad.
The second problem is confined to the southern Madison Range and Lionhead area. A layer of surface hoar and/or small facets are buried 1-2 feet deep. These are gaining strength, but can still avalanche. Luckily they are easy to spot as a dark stripe in a snowpit. These are worth digging for and testing. To be conservative I recommend skiing or sledding elsewhere if you find them.
For today, the avalanche danger is rated MODERATE on all slopes since human triggered avalanches are still possible.
Cooke City
Cooke City is loving life: deep snow and mostly stable conditions. This could change if winds increase and build slabs, but for the moment the place you may find unstable snow would be on lower elevation slopes that have thin snow cover (video). For today, the avalanche danger remains LOW.
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.
February 16: 11th Annual King and Queen of the Ridge
The Avalanche Center, Montana Ale Works and Beartooth Powder Guides have already entered as teams. Organize your own team or come out as an individual hiker. Better yet, let others do the hiking for you and donate instead! If you would like to donate to the Avalanche Center team of Mark and Eric (30 lap goal!) drop us a line at mtavalanche@gmail.com. Pledges can be made per lap or just a flat donation. Kids and families are encouraged to hike too! Prizes will be awarded to the most hikes (1st, 2nd, and 3rd); most money raised; most laps for a team; most money raised for a team. More Information / Registration Form
AVALANCHE EDUCATION
Cooke City: a free 1-hour Avalanche Awareness lecture at the Community Center, 6 p.m., Friday, February 15.
West Yellowstone: a free 1-hour Avalanche Awareness lecture at the Holiday Inn, 7 p.m., Friday, February 15.