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: Mostly cloudy. Southwest winds around 15 mph in the morning becoming south around 15 mph late in the afternoon. Highs 24°F to 30°F.

Tonight: Breezy...cloudy. Chance of snow in the evening...then snow after midnight. Snow accumulation of 1 to 2 inches. Southwest winds 15 to 20 mph. Chance of snow 80 percent. Lows 9°F to 15°F.

Sunday: Breezy. Snow likely. Snow accumulation of 1 to 2 inches. Southwest winds 15 to 20 mph. Chance of snow 60 percent. Highs 19°F to 25°F.

Sunday Night: Chance of snow in the evening...then snow likely after midnight. Snow accumulation of 1 to 2 inches. Southwest winds around 15 mph. Chance of snow 70 percent. Lows 10°F to 16°F.

Monday: Snow likely. Snow accumulation of 2 to 3 inches. Total snow accumulation 5 to 9 inches. Chance of snow 70 percent. Highs 19°F to 25°F.

Monday Night: Colder. Mostly cloudy with a 40 percent chance of snow. Lows -3°F to 5°F. Wind chill readings -11°F to -21°F.

Christmas Day / Tuesday: Partly cloudy. Highs 11°F to 17°F. * Merry Christmas *

Christmas Night / Tuesday Night: Partly cloudy. A 20 percent chance of snow in the evening. Lows -1°F to 5°F. * Merry Christmas *

Wednesday: Partly cloudy in the morning...then mostly cloudy with a 20 percent chance of snow in the afternoon. Highs 18°F to 24°F.

Wednesday Night: Mostly cloudy with a 50 percent chance of snow. Lows 9°F to 15°F.

Thursday: Mostly cloudy with a 40 percent chance of snow. Highs 19°F to 25°F.

Thursday Night: Mostly cloudy with a 40 percent chance of snow. Lows 4°F to 10°F.

Friday: Mostly cloudy with a 20 percent chance of snow. Highs 17°F to 23°F.

 Hazardous Weather Forecast  Gibbon Falls Forecast  Mammoth Forecast  Midway Forecast  Norris Forecast  Old Faithful Forecast 

Mountain Weather

This morning mountain temperatures were in the teens to low 20s Fahrenheit with a slight inversion and valley temperatures in the single digits or colder in places like West Yellowstone. Winds this morning were blowing 10to 15 mph from the south with gusts of 20 to 30 mph. Today cold air will descend over Southwest Montana keeping mountain temperatures from rising much. As a trough of low pressure approaches, south winds will increase and clouds will build this afternoon. Snowfall should begin late afternoon or early this evening mostly to the south. By tomorrow morning the mountains near West Yellowstone and Cooke City will get 3 to 5 inches of snow. Other areas will get 1 to 3 inches.

Snowpack and Avalanche Discussion:

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

Many places and many slopes have a deep and strong snowpack like one Eric found yesterday on Lionhead while teaching an avalanche class (strong snow photo). Some slopes like a steep, rocky one on Sacajawea Peak have much thinner and weaker snow. This particular slope was loaded by wind-blown snow and produced an avalanche (avalanche photo) on Thursday when triggered by a falling cornice. Throughout the advisory area, similar slopes will be likely places to trigger an avalanche. Other places to trigger an avalanche exist at lower elevations with relatively thin snow capped by wind slabs or drifts.

Yesterday my partner and I skied in Truman Gulch on the west side of the Bridger Range. As expected the snowpack was thinner and weaker than it is on the Bridger Bowl side but not necessarily unstable because it lacks the stress from new snow. However, we carefully avoided areas with wind drifted snow. Most interesting was the condition of the snow surface which has weakened and faceted during recent warm sunny days and clear cold nights. The Big Sky Ski Patrol has found similar weaknesses near the surface. This potential, future problem does not appear to be widespread but is worth remembering once more snow comes.

Interested in a summary of recent weather and the outlook for the next three months? It could be wetter and colder! Watch this short video from the National Weather Service in Billings.

Today, because human triggered avalanches remain possible the Avalanche Danger is rated MODERATE.

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.