Caution advised for snow falling off of building roofs. Park accordingly.

Dangerous avalanche conditions may already exist in many back country areas, please call the Recorded Avalanche Advisory 406-587-6981 for the most current conditions.

Today: Breezy. Mostly cloudy. Occasional flurries. Southwest winds 15 to 20 mph in the afternoon. Highs 5°F to 11°F. Lowest wind chill readings -16°F to -26°F in the morning.

Tonight: Breezy. Mostly cloudy with a 20 percent chance of snow. Southwest winds 15 to 20 mph with gusts to around 35 mph. Lows -5°F to 1°F. Wind chill readings -19°F to -29°F.

Thursday: Breezy. Not as cold. Partly cloudy. Southwest winds 15 to 20 mph. Highs 16°F to 22°F. Lowest wind chill readings -14°F to -24°F in the morning.

Thursday Night: Breezy. Partly cloudy. South winds 15 to 20 mph. Lows 3°F to 9°F.

Friday: Partly cloudy. A 20 percent chance of snow in the afternoon. Southwest winds around 15 mph. Highs 23°F to 29°F.

Friday Night: Partly cloudy. Lows 10°F to 16°F.

Saturday: Partly cloudy with a 20 percent chance of snow. Highs 24°F to 30°F.

Saturday Night: Mostly cloudy with a 20 percent chance of snow. Lows 13°F to 19°F.

Sunday: Breezy. Mostly cloudy with a 50 percent chance of snow. Highs 19°F to 25°F.

Sunday Night: Mostly cloudy with a 40 percent chance of snow. Lows 10°F to 16°F.

Monday: Mostly cloudy with a 50 percent chance of snow. Highs 16°F to 22°F.

Monday Night: Colder. Mostly cloudy with a 20 percent chance of snow. Lows -1°F to 5°F.

Christmas Day / Tuesday: Mostly cloudy in the morning then becoming partly cloudy. A 20 percent chance of snow. Highs 13°F to 21°F. * Merry Christmas *

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Mountain Weather

Under clear skies mountain temperatures are zero to minus five Fahrenheit with light westerly winds. There's no new snow to report, the first time in 14 days. Today will be sunny with temperatures rising into the low teens Fahrenheit. Winds will blow 10 to 20 mph out of the west, but become stronger from the southwest tonight. A high pressure system will keep skies clear and dry for the next two days.

Snowpack and Avalanche Discussion:

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

Finally, the snowpack gets a breather. A day without snowfall and strong winds has been rare; not that I'm complaining! Our snowpack is looking manageable so far. Weak layers of facets can be found near the ground on many slopes, but they are a problem on only a few. Our stability tests are showing increased strength and even more telling, with 14 days of snow load there have been hardly any avalanches. Even though steady and moderate snowfall has promoted stability, I still have two avalanche concerns today:

1. Wind-loaded slopes. Wind drifted, soft slab avalanches were triggered near ridgelines in the Bridger Range (photo). Wind drifts also naturally released in gullies near Cooke City (photo). Backcountry slopes with a wind-load were sensitive yesterday, but I expect them to be stubborn on lower-angled terrain today (less than 35 degrees).

2. Persistent weak layer. On a handful of slopes we are still getting unstable results in our snowpit tests due to poor snow structure (snowpit profile). There does not seem to be a common aspect associated with this, but a weak layer of angular facets is in the bottom one and a half feet of the snowpack. We have not seen, nor heard reports of recent signs of instability on this deep layer (i.e. collapsing, cracking or avalanches) outside of ski area explosives. However, crack propagation in our tests is a condition of instability and we do not throw these results out, we pay attention to them. The Extended Column Test (video tutorial) is a reliable way to test the snow.

Given the avalanche concerns associated with recent wind-loading along with a smattering of slopes that have poor snow structure, it's still possible to trigger avalanches today. For this reason I'm rating the Avalanche Danger MODERATE on all slopes.

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: 406-587-6984.

PHOTOS, SNOWPITS, and VIDEOS

1. For links to all photos and videos listed in the above report, please visit this Link.

2. We've recently uploaded more photos and snowpits to our web site, more than what are linked in the advisory.

3. We're creating a series of "How To…" stability test videos. So far we've got clips on performing a CT and ECT. There are located under Stability Tests on the Resources page.

Information provided by Doug Chabot, Mark Staples, and Eric Knoff from the Gallatin National Forest Avalanche Center. For Photos and Videos, please visit the Avalanche Centers Website!

If you have any snowpack or avalanche observations, drop them a line at mtavalanche@gmail.com or call: 406-587-6984.

For detailed Avalanche Terms utilized here, please see the Avalanche Glossary.