GNFAC Avalanche Forecast for Tue Feb 28, 2012

Not the Current Forecast

Good morning. This is Doug Chabot with the Gallatin National Forest Avalanche Advisory issued on Tuesday, February 28 at 7:30 a.m.  Javaman and Northern Lights Trading Company, sponsor today’s advisory. This advisory does not apply to operating ski areas.  

Mountain Weather

In the last 24 hours a trace to one inch of snow fell in the southern mountains. Temperatures are near 10F and east winds are light at 5-10 mph.  Today will be cloudy with snow showers near West Yellowstone and Cooke City while the rest of our area enjoys mostly sunny skies. Winds will shift to the northwest today, but remain light as temperatures rise into the high teens.  By morning I expect 2-3 inches in the southern mountains. 

Snowpack and Avalanche Discussion

The Bridger, Madison and Gallatin Ranges, the Lionhead area near West Yellowstone and the mountains around Cooke City:

As days pass without substantial loading, triggering avalanches becomes more difficult even though the weak layer can still fracture. Center-punching a big line is still risky business and might be for the rest of the season.  We are seeing skiers nibble around the edges of big avalanche paths and get away with it.  Don’t confuse “getting away with it” with stability.  Many folks skied off the summit of Saddle Peak on Friday without any problems.  They got away with it.  Yet only eight inches of snow on Saturday was enough to rip out the slope that night.  And let’s not forget that a skier took the ride of her life on Friday when she triggered a large slide off the south summit of Saddle during the same time that folks were getting away with skiing lines a few hundred yards away (photo).  Stability assessment was not terribly tricky then, but it’s becoming more so now. 

Eric, Karl and I toured near Hebgen Lake yesterday (video).  Other skiers in this area had widespread collapsing and cracking on Saturday, but we only found it in a few localized spots (photo).  Our stability tests are propagating cracks and taking more force to break with each passing day, yet there are a few facts we should not forget:

1.  Cracking or collapsing indicates slopes are dangerously close to avalanching.

2.  Our mountains have a widespread weak layer of small facets buried 1 ½ to 3 feet deep that were responsible for much of the recent avalanche activity.

3.  Avalanches may also break at the ground since many slopes have large, weak grains of depth hoar at its base.  Examples of this include Saddle Peak (photo1, photo2), the south side of Bradley Meadow and Wolverine Bowl (photo) in the Bridger Range.

4.  Just two days ago a skier remotely triggered an avalanche on a slope less than 35 degrees north of Big Sky; scary stuff.  And yesterday Moonlight Basin Ski Patrol noted a large slide on the northeast flank of Cedar Mountain.

5.  Natural activity is still being spotted around Cooke City (photo).  

Eric summed up our thoughts about the buried facets in yesterday’s video when he said, “We definitely do not trust it”.  We are remaining conservative and staying out of avalanche terrain. We are on the backside of an avalanche cycle and instability is less obvious. This is the time we can get surprised. Given the widespread weak layer, recent avalanche activity and cracking/collapsing, I’m rating the avalanche danger CONSIDERABLE on all slopes today.  

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.

Accident Reports

The accident reports for the avalanche fatality near Cooke City on February 22 and Friday’s avalanche on Saddle Peak are now available on our website.

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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