Today...Cloudy. Slight chance of snow in the morning...then chance of snow in the afternoon. Southwest winds around 15 mph. Chance of snow 50 percent. Highs 25°F to 31°F.

Tonight...Snow likely. Snow accumulation of 2 to 4 inches. Southwest winds around 15 mph. Chance of snow 70 percent. Lows 6°F to 12°F.

Sunday...Snow likely in the morning...then chance of snow in the afternoon. Snow accumulation of 1 to 2 inches. Total snow accumulation 3 to 6 inches. Chance of snow 70 percent. Highs 21°F to 27°F.

Sunday Night...Mostly cloudy. Chance of snow in the evening...then slight chance of snow after midnight. Chance of snow 30 percent. Lows 1°F to 7°F.

Monday - Washingtons Birthday...Breezy. Mostly cloudy. Slight chance of snow in the morning...then chance of snow in the afternoon. Southwest winds 15 to 20 mph. Chance of snow 40 percent. Highs 21°F to 27°F.

Monday Night...Mostly cloudy with a 40 percent chance of snow. Lows 7°F to 13°F.

Tuesday...Cloudy with a 50 percent chance of snow. Highs 23°F to 29°F.

Tuesday Night...Cloudy with a 50 percent chance of snow. Lows 14°F to 20°F.

Wednesday...Breezy. Cloudy with a 50 percent chance of snow. Highs 27°F to 33°F.

Wednesday Night...Breezy. Cloudy with a 50 percent chance of snow. Lows 10°F to 16°F.

Thursday...Cloudy with a 50 percent chance of snow. Highs 18°F to 24°F.

Thursday Night...Colder. Mostly cloudy in the evening then becoming partly cloudy. A 20 percent chance of snow. Lows 1°F to 7°F.

Friday...Not as cold. Mostly 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 a trace to one inch of snow has fallen over the mountains of our advisory area. Currently, mountain temperatures are in the teens Fahrenheit and winds are blowing out of the West-southwest at 10-20 mph. Today, temperatures will warm into the 20s Fahrenheit and winds will shift to the West-northwest blowing 15-25 mph. An approaching cold front will produce an increased chance of snow showers by this afternoon. 3 to 5 inches will likely accumulate in the mountains by tomorrow morning.

Snowpack and Avalanche Discussion:

The Bridger, Madison, and Gallatin Ranges, the Lionhead area near West Yellowstone, and the mountains around Cooke City:

Winter is doing its best to make an appearance. Fresh snow has fallen nearly every day this past week, making riding conditions some of the best of the year. As the snow gradually piles up, the snowpack is working to support the new load.

Although snow totals over the past week have been respectable, the light-dry nature of the snow has amounted to less than 1 inch of SWE in most areas. While this snowfall has not added a tremendous amount of stress to the snowpack, it has provided enough ammunition for moderate winds to build fresh wind slabs. These wind slabs are today's primary avalanche concern.

The most likely areas to find and trigger pockets of windblown snow will be the leeward side of upper elevation ridgelines. Cornices are a good clue as to which direction the wind has been blowing and slopes below cornices should be avoided. Yesterday, Mark was in Cooke City and found wind loaded slopes, specifically those with a southerly aspect to be the most unstable. A facet crust combination about a foot below the surface provided the proper structure for wind slabs to move. A skier in Hyalite found similar conditions on Thursday.

Recently formed wind slabs should stay manageable in size. I don't expect areas of windblown snow to propagate across entire ridgelines. However, it does not take a large slide to produce severe consequences.

A secondary concern is avalanches breaking on deeper layers in the snowpack. Yesterday, my partner and I toured to Ernie Miller Ridge from Bacon Rind. We found a poor snowpack structure and received unstable results during stability tests. Triggering an avalanche on deeper layers will require finding the right combination of a strong slab resting over a thin weak section of the snowpack. The most likely areas to find this condition would be in steep, upper elevation, rocky terrain.

Today, human triggered avalanches are likely on wind loaded slopes steeper than 35 degrees which have a CONSIDERABLE Avalanche Danger. Less steep, non-wind loaded slopes have a MODERATE Avalanche Danger.

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.