GNFAC Avalanche Advisory for Sat Feb 25, 2012

Not the Current Forecast

 

AVALANCHE WARNING


ISSUED ON FEBRUARY 25 2012 AT 5:00 pm

 The Gallatin National Forest Avalanche Center is issuing a Backcountry Avalanche Warning for the Bridger Range.  Heavy snowfall, high winds and an extremely weak snowpack are causing unstable conditions.  Today the avalanche danger is HIGH on all slopes.  Natural and human triggered avalanches are likely.  Avalanche terrain including avalanche runout zones should be avoided.

 You are urged to contact the Gallatin National Forest Avalanche Advisory for more detailed information.

 Website: www.mtavalanche.com/advisory

Avalanche Hotline: 406-587-6981

This warning will either be terminated or updated by 6:00 AM on February 26, 2012

     Goo morning. This is Mark Staples with the Gallatin National Forest Avalanche Advisory issued on Saturday, February 25 at 7:30 a.m.  The Yellowstone Club Community Foundation, in partnership with the Friends of the Avalanche Center, sponsors today’s advisory. This advisory does not apply to operating ski areas. 

SADDLE PEAK AVALANCHE

Yesterday a skier triggered an avalanche on the south summit of Saddle Peak (photo1, photo2, photo3). Ironically, a photo of this slope appeared on the front page of the Bozeman Daily Chronicle yesterday morning. She was the second person in a group of three to ski and was caught near the top when it broke. She was carried 1500 feet, injured and partially buried. Her partners quickly found her and called 911. Gallatin County Search and Rescue rescued her with a helicopter. A full report will be issued in the next few days. Pure luck is the only reason she was not killed. In the last 12 days, 9 people have been killed in avalanches in the U.S. and 6 of these occurred backcountry areas next to ski areas. This terrain is otherwise known as “sidecountry.”

Mountain Weather

Since yesterday a few places near Cooke City and West Yellowstone received a trace of new snow.  This morning ridgetop temperatures were in the mid teens F and W/SW winds were blowing 20-30 mph with gusts up to 60 mph. Today will be cold, windy, and snowy. Temperatures may climb a few degrees this morning before cold air moves into the area. Winds will blow mostly from the W at 25-40 mph. Snow will start falling early this morning. By tomorrow morning 4-6 inches will accumulate near Cooke City and West Yellowstone. Further north near Bozeman and Big Sky, 2-4 inches will accumulate.

Snowpack and Avalanche Discussion

The Bridger Range and the mountains around Cooke City: 

The Bridger Range and the mountains around Cooke City received the most snow during this week’s storm, and these areas had the most avalanches. An avalanche fatality occurred near Cooke City on Wednesday (video), and a skier luckily survived an avalanche on Saddle Peak yesterday. Skiers near Cooke City reported many natural avalanches in recent days. Some were breaking 1-3 ft deep just under the storm snow while others broke 4-6 ft deep at the ground. I was skiing and snowmobiling in the northern Bridgers near Sacajawea Peak and saw many natural avalanches as well. Some were a day or two old; others were very fresh. Many of these slides occurred on a layer of near-surface facets I found 2 weeks ago, and some broke at the ground (video). We posted photos of many of these avalanches on our photos page. Also, in the Crazy mountains just outside the advisory areas, many large avalanches both natural and human triggered have occurred. 

Today with increased winds readily transporting snow there will be more natural avalanches and skiers or riders will easily trigger avalanches as well. All wind loaded slopes have a HIGH avalanche danger. Non wind loaded slopes have a CONSIDERABLE avalanche danger.

The Gallatin and Madison Ranges and the Lionhead area near West Yellowstone:

The Gallatin and Madison Ranges and the Lionhead area near West Yellowstone are no less dangerous. Yesterday just north of Big Sky, a skier observed 6 natural avalanches that slid about 2 days ago. These occurred on most aspects at elevations between 9000 and 10000 ft.  They broke 1-4 feet deep. He also remotely triggered another (photo). Further south near the Taylor Fork drainage, NRCS folks also observed a few natural avalanches. Other slopes did not slide and are waiting for a skier or rider to trigger them.

Many avalanches fractured on a layer of weak, near surface facets that formed 1-2 weeks ago. This layer exists on all aspects in all areas. A few low elevation areas do not have it. When avalanches break on this layer, they can easily step down to facets near the ground. This scenario occurred yesterday on the “Wave” at Big Sky and two days ago in “Great Falls” at Moonlight Basin (photo). Today, dangerous avalanche conditions exist on all slopes and the avalanche danger is CONSIDERABLE.

Eric 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.

Events/Education

FREE 1-hr Avalanche Awareness Lecture, Friday, March 2, 7-8 p.m. at the West Yellowstone Holiday Inn in the room next to the bar.

31st Annual Pinhead Classic

Come to Bridger Bowl on Saturday, March 17th (St. Patrick’s Day) with telemark skis, AT skis, alpine skis, snowboards, split boards, or even snow blades. The theme is Snowpocalypse based on the wildly popular Mayan 2012 apocalypse. $30 gets you into the races, a pint glass, t-shirt, a good time, a raffle ticket, and food by Cafe Fresco. Pre-register at Mystery Ranch or Grizzly Ridge March 11-16. Visit http://pinheadclassic.com/ or the Pinhead Facebook page for more info.

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