current GALLATIN NATIONAL FOREST AVALANCHE ADVISORY SUNDAY, FEBRUARY 25TH, 1996 Good morning, this is Doug Chabot with your Gallatin National Forest Avalanche Advisory for Sunday, February 25th, issued at 7:30 am. The next advisory will be issued tomorrow morning. Today's advisory is sponsored by Friends of the Avalanche Center, an independent non-profit group supported by folks like you. This advisory does not apply to the local ski areas. The weather continues to produce snow. Yipee!!! There is a band of very moist air extending from the southwest that is colliding with an arctic air mass over our area. And the jet stream overhead is providing the needed dynamics to wring snow out of the clouds. Bridger Bowl is showing the most snowfall accumulation with another 16 inches in the last 24 hours. That brings their storm total to about 22 inches. To the south of us the storm has dropped anywhere from 6 inches to 2 feet of new snow. The ridge top winds in the Bridgers are averaging 30mph with gusts of 50 from the east and these should calm down a bit today. For all other areas the wind should be out of the southwest at 10 - 15 mph on the ridges. The temperatures are cooling off, with highs expected in the teens. This should make for a cold wind chill. The snow will continue today, with accumulations of 6-10 more inches in the mountains by tomorrow morning. That should be enough to satisfy the powder hounds in all of us! The mountains in our area continue to get loaded from the recent snowfall and widespread wind. This is creating various problems with the snowpack throughout our entire region. Karl and I went to Bacon Rind yesterday amidst the snowfall and swirling winds. This area is south of Big Sky, and the snow was deep. As we broke trail up to the ridge top we felt collapsing of the snow numerous times. With a closer look at the snowpack we found a buried surface hoar layer underneath all of the new snow that we received since Monday (about 2 1/2 feet). This layer was more prominent at the higher elevations and also on more northerly aspects. This layer is weak and is the main concern with the continued snow loading that we are currently getting. This buried hoar layer is consistent with the what has been observed in other areas in the southern mountains. In the northern areas this layer is absent, but other problems are developing there. And they relate to WIND. Southwest Montana has been quite a windy place these past few days. And if you step outside you'll see that today is no exception. In the Bridgers the wind has been blowing quite hard out of the east. The wind typically doesn't blow out of the east, so if you head into the Bridgers you'll have to pay particular attention to unusual loading conditions that these winds can cause. The Bridger Bowl Ski Patrol is reporting that the east winds are predominantly effecting snow from the ridge tops to about 300 feet down. Down in the southern areas the winds have been from the west-southwest. And they too have been blowing very hard. The Big Sky Ski Patrol is reporting widespread wind loading. It's also been reported to be quite windy in the mountains around Cooke City. Remember that wind is a wonderful transporter of snow. So with all the new snow that we've gotten, I recommend paying attention to the lee sides of ridge and gullies. This artificial loading could easily create avalanches, especially with a human trigger. It's also worth noting that there might be some wind slabs that are hidden from view because of all the fresh snow. So be extra careful as you travel around. We are very close to issuing an avalanche warning for the southern areas because of the recent loading and associated weak layers. Use extreme caution when traveling in the backcountry. Everyone should be familiar with identifying avalanche terrain and the quick use of an avalanche beacon. FOR TODAY I WOULD CALL THE SNOWPACK INSTABILITY HIGH ON ALL SLOPES STEEPER THAN 35 DEGREES IN THE BRIDGER, GALLATIN, AND MADISON RANGES. THIS INCLUDES THE LIONHEAD AREA OUTSIDE WEST YELLOWSTONE AND THE MOUNTAINS AROUND COOKE CITY. FOR SLOPES LESS THAN 35 DEGREES THE INSTABILITY IS MODERATE. But, please remember, that even with a moderate instability avalanches are possible, especially in light of all this snow and wind. If you're interested in increasing your avalanche skills, there is an advanced avalanche course being offered next week. The focus of the course will be to improve your backcountry decision making. Participants should have taken a basic avalanche course and feel good about using their avalanche beacon. The class is being offered through the ASMSU Outdoor Recreation Program, and will take place during the evenings of February 26th and 28th, with a field session on March 2nd. Pre-registration is required. Call 994-3621 for more information. Advisories are issued every day of the week except on Tuesdays. I will issue the next advisory tomorrow morning at 7:30 AM. If you have any recent snowpack or avalanche information to pass on, please give us a call at 587-6984. This advisory is also available on a recorded message at 587-6981 in Bozeman, 838-2341 in Cooke City, and 646-7912 in West Yellowstone. Advisories are available on the Internet at http://www.csac.org. [Submitted by: unknown (/s=k.birkeland/ou1=r01f11a@mhs-fswa.attmail.com) Sun, 25 Feb 1996 12:47:14 +0000]