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: Cloudy. Chance of snow in the morning...then scattered snow showers in the afternoon. Southwest winds around 15 mph late in the afternoon. Chance of snow 40 percent. Highs 13°F to 19°F.

Tonight: Areas of blowing snow in the evening. Snow likely. Snow accumulation of 1 to 2 inches. South winds around 15 mph. Chance of snow 60 percent. Lows 2°F to 8°F.

Tuesday: Breezy. Snow likely. Areas of blowing snow in the afternoon. Snow accumulation of 1 to 2 inches. Southwest winds around 15 mph shifting to the northwest in the afternoon. Chance of snow 70 percent. Highs 14°F to 20°F.

Tuesday Night: Areas of blowing snow in the evening. Snow likely. Snow accumulation of 1 to 2 inches. West winds around 15 mph. Chance of snow 60 percent. Lows 6°F to 12°F.

Wednesday: Breezy. Snow likely. Areas of blowing snow in the afternoon. Snow accumulation of 2 to 3 inches. West winds 15 to 20 mph. Chance of snow 70 percent. Highs 20°F to 26°F.

Wednesday Night: Snow likely. Light snow accumulations. Chance of snow 60 percent. Lows 11°F to 17°F.

Thursday: Mostly cloudy with a 40 percent chance of snow. Highs 22°F to 28°F.

Thursday Night: Mostly cloudy with a 40 percent chance of snow. Lows 14°F to 20°F.

Friday: Mostly cloudy with a 30 percent chance of snow. Highs 24°F to 30°F.

Friday Night: Colder. Partly cloudy. Lows 7°F to 13°F.

Saturday: Mostly sunny. Highs 25°F to 31°F.

Saturday Night: Mostly clear. Lows 12°F to 18°F.

Sunday: Mostly sunny in the morning then becoming partly cloudy. Highs 28°F to 34°F.

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

Mountain Weather

Since yesterday morning 6 to 8 inches of snow fell in the mountains around West Yellowstone and Big Sky including the northern Gallatin Range. The mountains around Cooke City picked up 4 to 5 inches while the Bridger Range squeezed out 3 inches. Today, snow showers will linger but accumulations will be less than an inch. Currently, temperatures are ranging from the single digits to low teens Fahrenheit and winds are light out West-northwest blowing at 5 to 15 mph. Today, temperatures will warm into the upper teens to low twenties Fahrenheit and winds will stay light to moderate out of the West-northwest. A stronger storm system will move into southwest Montana late tonight and last through tomorrow. Accumulations upward of a foot are possible by Wednesday morning.

Snowpack and Avalanche Discussion:

Cooke City, Southern Madison, Southern Gallatin Ranges, and the Lionhead area near West Yellowstone:

How much did it snow, where have the winds been blowing and what kind of surfaces did the new snow fall onto? These are the main questions we need to ask.

Upper elevation terrain around Cooke City has received close to a foot of snow over the past three days and has seen the strongest winds. However, this area lacks buried persistent weak layers which helps narrow the avalanche hazard down to wind loaded slopes. On Saturday, winds blew predominately out of the Southwest, but switched to the Northwest yesterday afternoon. A flip flop in wind direction will create fresh wind slabs on a variety of slopes, specifically those below ridgelines and around cross loaded terrain features. I don't expect wind slabs to propagate far, but they will likely break 1 to 2 feet deep producing enough debris to carry or bury a skier or rider.

The mountains around West Yellowstone including the northern Madison Range received close to ten inches of snow over the past three days. This latest round of snow has been deposited onto a layer of near surface facets and/or surface hoar (facets, surface hoar). These persistent weak layers have been preserved on a wide range of slopes throughout the southern areas. Winds out of West-northwest have been just strong enough to transport snow onto leeward slopes. Areas that have received any wind loading will be sensitive to the weight of skier or rider. Digging multiple snowpits to assess the strength and distribution of these buried weak layers is essential before committing to avalanche terrain.

Today, for the mountains around Cooke City, West Yellowstone and the southern Madison Range – Human triggered avalanches are likely on wind loaded slopes which have a CONSIDERABLE Avalanche Danger. Non-wind loaded slopes have a MODERATE Avalanche Danger.

Northern Gallatin, and Northern Madison Ranges:

Over the past 24 hours 5 to 8 inches of low density snow fell in the northern Madison and northern Gallatin Ranges. This storm came in warm and left cold, allowing the new snow to bond well to old snow surfaces. The lack of wind also helped prevent the avalanche hazard from rapidly increasing. Yesterday, the Big Sky Ski Patrol triggered a few small soft slab avalanches in steep-upper elevation terrain, but found the new snow to be mostly non-reactive.

Today, loose snow or soft slab avalanches are possible on wind loaded slopes and slopes steeper than 35 degrees which have a MODERATE Avalanche Danger. All other slopes have a LOW Avalanche Danger.

The Bridger Range:

The Bridger Range is not typically favored by a west-southwest flow, which proved to be the case with this latest storm. The new snow has bonded well to the old snow surface and the lack of wind has kept slab development to a minimum.

Today, unstable snow may be found on isolated terrain features, but generally safe avalanche conditions exist. For this reason the Avalanche Danger is rated LOW.

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.