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: Areas of blowing snow in the morning. Snow. Snow accumulation of 1 to 2 inches. Southwest winds around 15 mph. Chance of snow 90 percent. Highs 23°F to 29°F.

Tonight: Cloudy with snow likely. Areas of blowing snow. Snow accumulation of 1 to 3 inches. Southwest winds around 15 mph. Chance of snow 70 percent. Lows 14°F to 20°F.

Friday: Cloudy. Snow likely in the morning...then scattered snow showers in the afternoon. Snow accumulation of 1 to 2 inches. Total snow accumulation 3 to 11 inches. West winds around 15 mph. Chance of snow 60 percent. Highs 25°F to 31°F.

Friday Night: Colder. Mostly cloudy in the evening then becoming partly cloudy. Occasional flurries. Lows 3°F to 9°F.

Saturday: Mostly sunny. Highs 26°F to 32°F.

Saturday Night: Mostly clear. Lows 3°F to 11°F.

Sunday: Partly cloudy. Highs 26°F to 32°F.

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

Monday: Mostly cloudy with a 20 percent chance of snow. Highs 27°F to 33°F.

Monday Night: Partly cloudy. Lows 13°F to 19°F.

Tuesday: Partly cloudy. Highs 29°F to 35°F.

Tuesday Night: Partly cloudy. Lows 13°F to 19°F.

Wednesday: Mostly cloudy with a 30 percent chance of snow. Highs 28°F to 34°F.

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Mountain Weather

Since yesterday morning 15 inches of snow fell in Hyalite Canyon, 10 to 12 inches near Bridger Bowl, 8 to 9 inches near Big Sky and Cooke City, and 2 to 6 inches near West Yellowstone. Westerly winds have been averaging 20 mph and gusting to 40 to 50 mph. This morning temperatures were in the high teens Fahrenheit and should rise to the low 20s Fahrenheit today. Winds will remain westerly and ease slightly, blowing 15 mph with gusts of 30 to 35 mph. Snowfall will continue today. By tomorrow morning most areas will get an additional 3 to 6 inches. The mountains near West Yellowstone will receive 2 to 3 inches.

Snowpack and Avalanche Discussion:

Cooke City:

The mountains near Cooke City have a single avalanche problem – fresh wind slabs. This area mostly lacks buried weak layers of facets. For today the Avalanche Danger is CONSIDERABLE on wind loaded slopes and MODERATE Avalanche Danger on all others.

Madison, and Southern Gallatin Ranges, and Lionhead Area near West Yellowstone:

Areas further south received less snow but plenty of wind making fresh wind slabs the primary avalanche problem. Another problem is several layers (video, photo) of weak facets (and some surface hoar - photo) that formed on the snow surface during dry weather in both early and mid-January. They are now buried 1 to 2 feet deep. These layers are widespread closer to West Yellowstone. They also exist near Big Sky on many slopes but seem to be more sensitive on south aspects. New snow, wind, and buried weak layers mean dangerous avalanche conditions exist today and the Avalanche Danger is rated CONSIDERABLE.

Bridger and Northern Gallatin Ranges:

The message for today is simple. Heavy snowfall plus strong winds will create both natural and human triggered avalanches. There are three avalanche problems which are interesting to discuss but irrelevant to the travel advice today. Avoid avalanche terrain.

1. Strong winds have created fresh drifts and wind slabs. Doug and Eric intentionally triggered a small avalanche yesterday on a little test slope that had fresh wind drift. More will occur today.

2. Yesterday's snow is much denser (12% at Bridger) than Tuesday's snow (3%) creating upside down conditions. This set up caused Doug and Eric to back off a 32 degree slope yesterday (video).

3. Some slopes, especially in the northern Gallatin Range, have a thin, weak snowpack. Skiers on Mount Ellis found a very weak snowpack, 2 to 2.5 feet deep. Similar slopes exist in Hyalite Canyon. With 1.2 to 1.6 inches of snow water equivalent falling in the last 24 hours, these slopes will not be able to support this much weight and may produce avalanches breaking deeper in the snowpack.

Today, the Avalanche Danger is rated HIGH on wind loaded slopes and the Avalanche Danger CONSIDERABLE on all others.

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.

EDUCATION, PHOTOS, SNOWPITS, and VIDEOS

1. For links to Articles, Education and (photos), (snowpits), or (videos) listed in the above report, please visit this Link.

2. They have recently uploaded more photos and snowpits to their web site, more than what are linked in the advisory above.

3. They have creating a series of "How To…" stability test videos. So far they have clips on performing a CT and ECT. They are located under Stability Tests on their 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.