Good morning. This is Mark Staples with the Gallatin National Forest Avalanche Advisory issued on Friday, February 15 at 7:30 a.m. Helio Collective and Javaman sponsor today’s advisory. This advisory does not apply to operating ski areas.
Since yesterday the northern Gallatin Range received 5 inches of new snow and probably more up high in Hyalite Canyon. The Bridger Range, northern Madison Range and mountains near Cooke City received 2-3 inches. The mountains closer to West Yellowstone received a trace to one inch. This morning temperatures were in the low teens F and winds were averaging 10-15 mph from the W and NW with gusts of 20-25 mph. Today will be partly sunny with temperatures around 20 degrees F. Winds will blow 10 mph and gust to 25 mph from the W and NW. Saturday should be sunny with more snow coming Sunday.
Northern Gallatin Range
The northern Gallatin Range which includes Mt Ellis, Hyalite Canyon, and the Little Bear area, has two factors contributing to poor stability. This area received more snow than other places recently, and it has layers of weak facets on many slopes. Skiers on Mt Wheeler found a poor snowpack structure (photo) and a small recent avalanche, both red flags. A group of skiers in Hyalite Canyon triggered one small avalanche and saw several others all about 12-14 inches deep involving new snow with some wind loading.
Avalanches may easily break deeper in the snowpack on weak faceted layers now buried 2-3 feet deep (photo1, photo2). Late last night, ridgetop winds averaged 20 mph which is perfect for moving fresh powder. Today with new snow, wind, and widespread buried weak layers, the avalanche danger is CONSIDERABLE.
Cooke City
In the last 48 hours the Fisher Creek SNOTEL site reported 0.8 inches of snow water equivalent, but there is almost double this amount in places which means 1.5 feet of new snow. Winds yesterday afternoon were blowing 25-40 mph from the NW and averaging close to 20 mph this morning, perfect speeds for drifting the fresh powder. Yesterday a skier spotted several small avalanches, ski cut one, and experienced cracking in the new snow.
Stability evaluations are relatively simple in this area because the main avalanche problem is new snow and wind-blown snow. The exception is low elevation areas that have weak facets near the ground. In one of these areas 11 days ago a rider remotely triggered an avalanche following heavy snowfall. Today the avalanche danger is rated CONSIDERABLE on wind loaded slopes steeper than 35 degrees. All other slopes have a MODERATE avalanche danger.
Bridger Range Madison Range Southern Gallatin Range
Lionhead area near West Yellowstone
In the Bridger Range and the mountains near Big Sky and West Yellowstone, there has been light snowfall during the last few days and relatively light winds which were averaging 10-15 mph this morning. Yesterday ski patrols reported that wind loaded areas were not very reactive. The main concern is a layer of facets buried 1-2 feet deep (photo). This layer is more widespread closer to West Yellowstone. I don’t expect many avalanches on it, but I would be looking for this layer before riding or skiing in avalanche terrain. The presence of this layer means human triggered avalanche are possible and the avalanche danger is rated MODERATE.
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.
Avalanche on Alex Lowe Peak in Hyalite – Read the accident report with a video, photos, and a snowpit; all posted here.
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: TODAY, a free 1-hour Avalanche Awareness lecture at the Community Center, 6 p.m.
West Yellowstone: TODAY, a free 1-hour Avalanche Awareness lecture at the Holiday Inn, 7 p.m.