Rest Of Today...Breezy. Snow late in the morning...then snow likely in the afternoon. New snow accumulation around 2 inches. Total snow accumulation 4 to 6 inches. Highs 22°F to 28°F. Northwest winds 20 to 25 mph. Chance of snow near 100 percent.

Today...Mostly cloudy. Slight chance of snow in the morning...then chance of snow in the afternoon. Highs 20°F to 26°F. Southwest winds around 15 mph in the morning becoming southwest around 15 mph late in the afternoon. Chance of snow 30 percent. Lowest wind chill readings -11°F to -21°F in the morning.

Tonight...Cloudy with a 40 percent chance of snow. Lows 6°F to 12°F. Southwest winds around 15 mph in the late evening and early morning.

Monday...Mostly cloudy with a 50 percent chance of snow. Highs 23°F to 29°F.

Monday Night...Chance of snow in the evening...then snow likely after midnight. Snow accumulation of 3 to 4 inches. Lows 14°F to 20°F. Chance of snow 70 percent.

Tuesday...Cloudy. Chance of snow in the morning...then scattered snow showers in the afternoon. Highs 25°F to 31°F. Chance of snow 50 percent.

Tuesday Night...Mostly cloudy in the evening then becoming partly cloudy. A 20 percent chance of snow. Lows 9°F to 15°F.

Wednesday...Mostly cloudy in the morning then becoming partly cloudy. Highs 27°F to 33°F.

Wednesday Night...Partly cloudy. Lows 7°F to 15°F.

Thursday...Partly cloudy. Highs 30°F to 36°F.

Thursday Night...Partly cloudy. Lows 11°F to 17°F.

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

Friday Night...Colder. Mostly cloudy in the evening then becoming partly cloudy. A 20 percent chance of snow. Lows 4°F to 12°F.

Saturday...Partly cloudy. Highs 22°F to 28°F.

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

Mountain Weather

Over the past 24 hours 2-3 inches of snow has fallen in the mountains around Cooke City, while the rest of our advisory area has remained dry. Light cloud cover overnight has kept mountain temperatures in the mid to high teens and winds are currently blowing out the West at 20-30 mph with ridgetop gusts reaching 40 mph in Hyalite and Big Sky. Today, temperatures will climb into the high 20s Fahrenheit and winds will stay moderate out of the West at 10-20 mph. Skies will remain mostly cloudy today as a weak short wave passes to our north; however, no snow is expected over the next 24 hours.

Snowpack and Avalanche Discussion:

The Madison Range, and southern Gallatin Range, the Lionhead area near West Yellowstone, the mountains around Cooke City and the Washburn Range:

The mountains around Cooke City have received snow ten out of the last eleven days totaling 5.5 inches of water (Snow Water Equivlent). This adds up to nearly six feet of snow! When snow of this quantity was combined with strong winds, the resulting load simply pushed the snowpack beyond its breaking point. Yesterday, a skier near Round Lake outside of Cooke City triggered and was caught in a slide resulting in minor injuries. This heavy load also produced large natural avalanches on Mount Republic just outside of town. With a load of this magnitude, avoiding wind loaded terrain and staying out from avalanche run out zones is highly advised. The mountains around Big Sky and West Yellowstone have received roughly have the amount of snow Cooke City has, but the cumulative totals still add up to more than 2.5 inches of water. Yesterday, the Big Sky Ski Patrol triggered multiple slides with explosives that failed on facets deep in the snowpack. These slides occurred mainly on south facing slopes that likely had a weak, faceted snowpack prior to this latest round of storms. The ski patrol regularly controls these areas, but the collective load over the past week was enough to push these slopes over the edge. The possibility of triggering a slide on these deeper layers in the backcountry remains a possibility - riders should be carefully aware that a resulting avalanche could be large and quite dangerous. Today, carful snowpack evaluation, cautious route finding and conservative decision making are essential when traveling in the backcountry.

With a snowpack still under stress – human triggered avalanches are likely on all wind loaded slopes where the Avalanche Danger is rated CONSIDERABLE. Slopes that have not received a wind load have a MODERATE Avalanche Danger.

The Bridger Range and northern Gallatin Range:

A brief ridge of high pressure has helped stabilize the weather, which in return has helped stabilize the snowpack. The few inches of high density snow that fell on Friday night has bonded well with the old snow surface and has offered little in the way of transport. Yesterday, the Bridger Bowl Ski Patrol reported minimal cornice and pillow growth along the ridgeline, and mentioned the 3 inches of new snow skied more like 6 inches.

Most areas in the Bridger Range and northern Gallatin Range have a relatively stable snowpack, however, pockets of instability can be found. Steep, upper elevation slopes that have received wind loading over the past week remain our primary avalanche concern. Yesterday, skiers in the northern Bridger Range near Fairy Lake observed the remnants of a large natural slide that occurred on the south face of Hardscrabble Peak. This slide broke 2-3 feet deep, 200 yards across and ran close to 1,000 vertical feet. Although this slide happened earlier in the week, it's a good reminder of what's possible.

Today, human triggered avalanches are possible and the Avalanche Danger is rated MODERATE.

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

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.