TUESDAY, DECEMBER 26th Good morning, this is Doug Chabot with your Gallatin National Forest Avalanche Advisory issued on Tuesday, December 26th, at 7:30 am. The Montana Fish, Wildlife and Parks Recreation Trail Program sponsor today's advisory, which does not apply to operating ski areas. CURRENT CONDITIONS AND WEATHER DISCUSSION: Yesterday was a beautiful Christmas day and today looks like it'll be more of the same. We had no new snow in the last 24 hours since we're under the influence of a drier, high-pressure airmass. This weather should continue throughout today bringing warmer mountain temperatures into the high twenties with partly cloudy skies and no real chance of precipitation. Our ridgetop winds have remained light at 10-20 mph out of the west to northwest, with the exception being the Bridger's that saw 30-50 mph yesterday. Today our winds will again be from the west to northwest at 10-20 mph, but increasing tonight as the ridge flattens. SNOWPACK AND AVALANCHE DISCUSSION: The Lionhead area near West Yellowstone, the mountains around Cooke City, the southern Madison, southern Gallatin and Washburn Ranges: Our southern mountains continue to be our biggest concern since these areas have the weakest and most unstable snow. Our observations in Cooke City and the southern Madison's show a weaker base underlying a slab of various depth in most locations. This weak layer of loose, faceted snow is easy to identify since it resembles sugar, however you may have to dig a few feet to find it. If you head out riding and get off the trail you'll notice that the sled digs down into this layer resulting in poor traction. If you're skiing you can easily feel the density difference with your ski pole. In many of our southern areas there was an avalanche cycle that happened on the 15th and 16th during a large storm. You should still be able to see evidence of this from the fracture lines, although since that time these mountains have received about 2 BD inches of water that translates into 3 feet of new snow. All this new weight should keep things on the touchy side given the persistent nature of this weak layer. Our stability tests indicate that this layer is susceptible to human triggering, so for today, I consider the avalanche danger to be CONSIDERABLE. Use extra caution traveling onto steeper or wind loaded slopes since these would be under the most stress and consequently more unstable. The northern Gallatin and northern Madison Ranges and the Bridger Range: Even though we have a similar weak layer in our northern areas, in general the snowpack is more stable than down south since these faceted crystals near the ground are stronger. The dividing line between the two areas is fuzzy, but our field observations indicate that it lies near Big Sky. Ron and Karl went to the Windy Pass area in the Gallatin Range and found this area closely resembles our northern areas. Notice that I'm using words like "most" or "generally". That's because it's possible to find isolated areas where this is not necessarily the case. For example, I was in the northern Gallatin's on Sunday and found incredibly weak snow whose only saving grace was that it didn't have much of a slab on top of it to avalanche. What this variability means for you is that you'll have to be extra observant and poke around a bit to get an accurate assessment of the slope you plan on playing on. This is a good idea anytime of the year, but given the nature of this weak layer its especially prudent now. In the last week close to a foot of snow has fallen, and according to the Big Sky Ski Patrol there are a few touchy pockets out there. Besides finding these on avalanche control yesterday they also observed a few smaller natural slides that happened out-of-bounds. With human triggered slides possible, for today, I consider the avalanche danger to be MODERATE. END