Rest Of Today...Partly cloudy. Highs 14°F to 20°F. West winds around 15 mph late in the afternoon.

Tonight...Breezy. Partly cloudy with a 20 percent chance of snow. Lows 0°F to 6°F. Southwest winds 15 to 20 mph. Wind chill readings -10°F to -20°F.

Saturday...Breezy. Partly cloudy in the morning then becoming mostly cloudy. A 20 percent chance of snow. Highs 18°F to 24°F. Southwest winds 15 to 20 mph. Lowest wind chill readings -10°F to -20°F in the morning.

Saturday Night...Breezy. Mostly cloudy with a 20 percent chance of snow. Lows 7°F to 13°F. Southwest winds 15 to 20 mph.

Sunday...Mostly cloudy. Chance of snow in the morning...then slight chance of snow in the afternoon. Highs 24°F to 30°F. Southwest winds around 15 mph. Chance of snow 30 percent.

Sunday Night...Mostly cloudy with a 20 percent chance of snow. Lows 12°F to 18°F.

Monday...Mostly cloudy with a 50 percent chance of snow. Highs 25°F to 31°F.

Monday Night...Mostly cloudy with chance of snow in the evening... Then partly cloudy with slight chance of snow after midnight. Lows 9°F to 15°F. Chance of snow 40 percent.

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

Tuesday Night...Mostly cloudy in the evening then becoming partly cloudy. A 40 percent chance of snow. Lows 10°F to 16°F.

Wednesday...Mostly cloudy with a 40 percent chance of snow. Highs 25°F to 31°F.

Wednesday Night...Partly cloudy with a 20 percent chance of snow. Lows 10°F to 16°F.

Thursday...Partly cloudy with a 20 percent chance of snow. Highs 26°F to 32°F.

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

Mountain Weather

Since yesterday morning, 1 to 2 inches of snow fell near Big Sky and the Taylor Fork. 4 to 5 inches fell near Cooke City and West Yellowstone. Temperatures this morning dropped into the single digits Fahrenheit with winds blowing 20-40 mph from the West and Northwest. Today skies will clear, temperatures will warm into the teens Fahrenheit, and winds will blow 15-30 mph from the West and Northwest. Tomorrow should be warmer and the next chance of snow may not come until early next week.

Snowpack and Avalanche Discussion:

The southern Madison and southern Gallatin Ranges, and the Lionhead area near West Yellowstone:

The weakest and most unstable snowpack exists in the Lionhead area near West Yellowstone and the southern Madison Range. In the last 12 days, the Madison Plateau SNOTEL recorded 4.6 inches of snow water equivalent and the Carrot Basin SNOTEL recorded 2.7 inches. The weak snowpack will be evident when you step off your sled or out of your skis and sink to the ground. Riding at Lionhead on Tuesday, I saw many avalanches. Some occurred after only 2 inches of snow and wind. With 5 inches of snow yesterday and continued strong winds, there will be more avalanches. Some slopes may avalanche again, and it is still possible to trigger slopes from flat terrain underneath them. For today, wind loaded slopes steeper than 35 degrees have a HIGH Avalanche Danger. All other slopes have a CONSIDERABLE Avalanche Danger.

The mountains around Cooke City:

The mountains near Cooke City have received 6 inches of snow water equivalent over the last 12 days. This amount of water is about 60 inches of snow, which has added significant stress to the snowpack. When you add enough stress, things break. Many avalanches near Cooke City broke on a weak layer of facets near an ice crust on South facing slopes. During the last 2 days Doug consistently found this layer buried 2 to 3 feet deep, and I found it in the Sheep Creek drainage 2 weeks ago. North facing slopes are more variable. Some have a relatively strong snowpack. Others have weak facets near the ground. As snowfall buries these facets deeper, it will be harder to trigger an avalanche, but when you do, it will be big and deadly. Don't be fooled by tracks on a slope – these do not indicate stability. Today human triggered avalanches are likely and the Avalanche Danger is CONSIDERABLE.

The Northern Madison Range:

Although the mountains near Big Sky have not received as much snow as areas further south, snow has been steadily falling and adding up to 2.3 inches of snow water equivalent during the last 12 days. Yesterday on Yellow Mountain on southerly aspects, Eric and I found a layer of facets on top of an ice crust buried about 12 inches deep. On northerly aspects there was no ice crust but plenty of facets. We triggered an avalanche in a pocket with a heavy wind load that broke on facets near the ground. Snowfall has not been enough to push facets in the snowpack to their breaking point, but very strong winds during the last few days have loaded some slopes to their breaking point. It is on these slopes where you will get an avalanche. For today, wind loaded slopes steeper than 35 degrees have a CONSIDERABLE avalanche danger. Other slopes have a MODERATE Avalanche Danger.

The Bridger and northern Gallatin Ranges:

With less snow, the mountains near Bozeman have had less avalanches than other areas, but these mountains received very strong winds during the last 2 days leaving few slopes unaffected. Skiers on Mount Blackmore found big drifts well below treeline. The Bridger Range has a very weak snowpack. Triggering a wind slab will create an avalanche that will step down and avalanche on deeper layers in the snowpack. In Hyalite Canyon, the snowpack is mostly strong and avalanches will be confined to fresh wind slabs. For today with heightened avalanche conditions on specific terrain features, the Avalanche Danger is 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.

Beacon Parks

The Friends of the Avalanche Center installed a Beacon Training Park outside West Yellowstone. It's located south of town on the main snowmobile trail. Stop by and do a quick practice before heading off into the mountains!

EDUCATION, EVENTS, PHOTOS, SNOWPITS, and VIDEOS

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

2. 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.

3. Check out all our education programs, Click Here.

Information provided by Doug Chabot, Mark Staples, and Eric Knoff from the Gallatin National Forest Avalanche Center. For Events and Education, or 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.