Today...Partly cloudy. A 20 percent chance of snow in the afternoon. Highs 16°F to 22°F. Lowest wind chill readings -15°F to -25°F in the morning.

Tonight...Mostly clear in the evening then becoming partly cloudy. Lows -4°F to 4°F.

Friday...Partly cloudy. Highs 20°F to 26°F. Southwest winds around 15 mph in the afternoon. Lowest wind chill readings -11°F to -21°F in the morning.

Friday Night...Partly cloudy in the evening then clearing. Lows 1°F to 9°F. Southwest winds around 15 mph in the evening.

Saturday...Partly cloudy. Highs 24°F to 30°F. Southwest winds around 15 mph in the afternoon.

Saturday Night...Partly cloudy. Lows 9°F to 15°F.

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

Sunday Night...Colder. Mostly cloudy with a 50 percent chance of snow. Lows 0°F to 6°F.

Monday / Martin Luther King Jr Day...Cloudy with a 50 percent chance of snow. Highs 14°F to 20°F.

Monday Night / Martin Luther King Jr Day...Mostly cloudy with a 20 percent chance of snow. Lows -2°F to 4°F.

Tuesday...Breezy. Mostly cloudy with a 40 percent chance of snow. Highs 16°F to 22°F.

Tuesday Night...Breezy. Cloudy with a 50 percent chance of snow. Lows 2°F to 8°F.

Wednesday...Breezy. Cloudy with a 50 percent chance of snow. Highs 22°F to 28°F.

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Mountain Weather

This morning mountain temperatures were in the low teens Fahrenheit except near West Yellowstone and Cooke City where temperatures were near 0 degrees Fahrenheit. Ridgetop winds were averaging 15-25 mph mostly from the NW. A ridge of high pressure off the west coast is affecting our weather by blocking moisture and creating a Northwest flow over Montana, a common pattern this winter. This ridge will hopefully flatten late this weekend allowing a chance of precipitation. Today will be mostly sunny with some clouds, temperatures will rise into the low 20s in most areas, and ridgetop winds will blow 10-25 mph from the Northwest.

Snowpack and Avalanche Discussion:

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

Now is a difficult time. Since the large storm on New Year's Eve, the snowpack has adjusted to the stress of that snow, and it has become harder to trigger an avalanche. Signs of instability are not obvious. Yesterday I skied in the Sheep Creek drainage north of Cooke City where the snowpack gave me a false sense of security because it felt "good" under my skis. This feeling does not mean slopes were stable and I was easily tricked. With a sharp eye, my partner pointed out many avalanche crowns from last week that were not easy to see. Weak layers in the snowpack were not obvious either because there is a supportable slab covering them. The only way to identify these weak layers is to dig a snowpit and perform stability tests.

In most areas 1 to 2 feet of snow rest on top of a variety of weak layers including buried surface hoar, near-surface facets, and depth hoar. Yesterday on Mount Ellis in the northern Gallatin Range, Doug found buried surface hoar. It gave him no signs of instability until he dug a snowpit. It was an obvious stripe in the snowpit wall and easily fractured in stability tests. Nearby in Hyalite Canyon, conditions are generally more stable, but some slopes have a weak layer buried about 2 feet deep. To further complicate matters near West Yellowstone, yesterday's fresh snow capped another layer of surface hoar that will be a future concern. This layer was also observed near Big Sky by the Moonlight Basin Ski Patrol where it exists on slopes sheltered from the wind.

On isolated slopes, winds blew yesterday's snow into drifts and formed fresh wind slabs. These drifts and wind slabs should not be trusted. They can make the difference between slopes that avalanche and ones that do not. Karl showed this difference in a recent video taken in the Bridger Range.

Riding in avalanche terrain now is like running a yellow light that turns red just as you pass through the intersection. You can get away with it sometimes, but eventually you'll either get a ticket or cause an accident. Today human triggered avalanches are definitely possible, and the Avalanche Danger is 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.