Today...Partly cloudy. Highs 7°F to 13°F. Northwest winds around 15 mph. Lowest wind chill readings -17°F to -27°F in the morning.

Tonight...Mostly clear. Lows -6°F to -12°F.

Thursday...Not as cold. Partly cloudy in the morning then clearing. Highs 17°F to 23°F. Lowest wind chill readings -15°F to -25°F in the morning.

Thursday Night...Mostly clear in the evening then becoming partly cloudy. Lows -3°F to 5°F.

Friday...Partly cloudy. Highs 21°F to 27°F. Southwest winds around 15 mph in the afternoon.

Friday Night...Partly cloudy. Lows 3°F to 11°F.

Saturday...Partly cloudy in the morning then clearing. Highs 24°F to 30°F.

Saturday Night...Mostly clear. Lows 8°F to 14°F.

Sunday...Partly cloudy. A 20 percent chance of snow in the afternoon. Highs 25°F to 31°F.

Sunday Night...Partly cloudy with slight chance of snow in the evening...then mostly cloudy with chance of snow after midnight. Lows 7°F to 13°F. Chance of snow 40 percent.

Monday / Martin Luther King Jr Day...Mostly cloudy with a 40 percent chance of snow. Highs 20°F to 26°F.

Monday Night / Martin Luther King Jr Day...Partly cloudy with a 20 percent chance of snow. Lows 2°F to 8°F.

Tuesday...Mostly cloudy with a 30 percent chance of snow. Highs 18°F to 24°F.

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

Mountain Weather

Everyone got an equal helping of cold temperatures and wind, but not snow. The Bridger Range along with West Yellowstone got skunked and only picked up an inch. The northern Gallatin Range and mountains around Cooke City got 6 to 8 inches while the Big Sky area and southern Madison Range got 3 to 5 inches. Mountain temperatures this morning are 0°F to -10°F with 5-10 mph winds out of the northwest, but 20 mph out of the east in Cooke City. As the snow fell yesterday, west to northwest winds blew strong and averaged 20-30 mph with gusts over 40 mph. Today will be sunny, temperatures will rise into the teens Fahrenheit and winds will remain calm. The next snowfall is predicted to be - Sunday night.

Snowpack and Avalanche Discussion:

The Bridger Range and Lionhead area near West Yellowstone:

The Bridger Range and Lionhead area near West Yellowstone only got an inch of snow. Winds were strong yesterday, but without snow to move around, the effects will be minimal. Although geographically far apart, these two areas have similar concerns of weak, faceted snow at the ground that is capped by a slab of snow. In West Yellowstone the inch of snow was enough to cap a layer of surface hoar, an additional problematic layer in the snowpack. Karl Birkeland was in the Bridger Range yesterday and found that slopes with a slight wind-load would propagate fractures, while those without would not. For today, the Avalanche Danger is rated MODERATE on all slopes since it's still possible to trigger avalanches on the buried, weak facets. As Karl showed in his video, slight terrain changes effect the snowpack and avalanche potential. He described the danger to me as "Heads-Up Moderate."

Madison and Gallatin Ranges, and the mountains around Cooke City:

Yesterday's snow was light density, 5% powder. Less than half an inch of water (SWE) fell in the Gallatin, Madison and Cooke City Ranges. This will not add much stress to the snowpack except in areas wind-loaded with the storm. Eight inches of airy fluff are now blown into 1 to 2 foot thick drifts. Winds were not confined to the ridgetops either; strong winds cross-loaded lower slopes too. With anemometers showing north to west winds at ridges and south to east winds at lower elevations, you'll be able to find wind-loading on most aspects. To complicate things further, Cooke City even has ridgetop winds blowing from the rare direction of east.

The avalanche message is simple: Wind-loading is bad. Our mountains have various layers of weak, sugary facets that will have a difficult time supporting a wind drift. The snow surface before the storm was also feathery crystals of surface hoar and near surface facets, now buried and unstable. The Avalanche Danger is rated CONSIDERABLE on all wind-loaded terrain today, no matter its steepness. Even slopes slightly wind-loaded will be sensitive to triggering. On sheltered slopes the Avalanche Danger is rated MODERATE.

Beacon Parks

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

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, 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.