Sunday, February 11th, 2007 Good morning. This is Scott Schmidt with the Gallatin National Forest Avalanche Advisory issued Sunday, February 11, at 7:30 a.m. The Yellowstone Club, in cooperation with the Friends of the Avalanche Center, sponsor todays advisory. This advisory does not apply to operating ski areas. MOUNTAIN WEATHER Three to four inches of snow has fallen in the mountains around Big Sky and West Yellowstone this morning, with a trace to one inch in the mountains around Bozeman and Cooke City. Winds have been 10 20 mph from the southwest and morning temperatures are in the low 20s. Skies will be partly cloudy this morning with snow showers resuming this afternoon. Accumulations of 4 8 inches of snow are likely over the next 24 hours with the heaviest snowfall in the southern mountains. Winds will be from the west/southwest at 10 20 mph and mountain temperatures will be in the mid-20s. SNOWPACK AND AVALANCHE DISCUSSION The Bridger and northern Gallatin Ranges: Over 2 inches of water have been added to the snowpack in the Bridger Range in the past 60 hours. This has finally tipped the balance. Large natural avalanches were reported on Saddle and Bridger Peaks yesterday. The Bridger Ski Patrol released several large slides in the ski area and in the Slushmans drainage using artillery. A skier just north of the ski area boundary was caught in an avalanche but luckily escaped uninjured. One of our regular observers was snowmobiling up the north fork of Bracket Creek. She reported several natural avalanches and her party remotely triggered three slides while riding in the flats. With very little new load overnight, the snowpack will adjust to the added weight and natural avalanche are not likely today; however, this stability is precarious. The added weight of a skier or snowmachine is likely to trigger a avalanche. All steep slopes in the Bridger and northern Gallatin Ranges should be avoided today. The avalanche danger in these mountains is CONSIDERABLE on all wind-loaded slopes, and on non-wind-loaded slopes steeper then 35 degrees. Non-wind-loaded slopes that are less steep have a MODERATE danger.