Today: Increasing clouds, with a high near 29°F. Wind chill values as low as -5°F. Southwest wind around 10 mph.

Tonight: A 50 percent chance of snow. Mostly cloudy, with a low around 6°F. Wind chill values as low as -5°F. North northwest wind between 6 and 8 mph. New snow accumulation of less than one inch possible.

Monday: Mostly sunny, with a high near 24°F and a low around 1°F. Wind chill values as low as -10°F. North northwest wind between 5 and 8 mph.

Tuesday: Mostly sunny, with a high near 26°F and a low around 7°F. South southeast wind 5 to 7 mph becoming west.

Wednesday: A 50 percent chance of snow. Mostly cloudy, with a high near 21°F and a low around -6°F. West wind around 8 mph.

Thursday: Mostly sunny, with a high near 17°F and a low around -5°F.

Friday: Mostly sunny, with a high near 21°F and a low around 0°F.

Saturday: A slight chance of snow. Mostly sunny, with a high near 22°F.

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Mountain Weather

Yesterday was a warm day with mountain temperatures reaching above freezing. Under a slight inversion, temperatures at 5:00 a.m. are in the high 20s Fahrenheit as westerly winds blow 20-30 mph in the north and 10-20 mph in the southern mountains. A cold front drops in later this afternoon which will bring a small, but welcome shot of snow. I'm expecting 1 to 2 inches tonight as temperatures drop into the teens Fahrenheit with west to northwest winds blowing 15-25 mph.

Snowpack and Avalanche Discussion:

The Bridger, Gallatin and Madison Ranges, the Lionhead area near West Yellowstone:

Sometimes when I'm trying to figure out how to describe an avalanche problem, I think of what I might tell my mom. If my mom was a backcountry skier I'd give her a few key pieces of information to keep her extra safe:

1. Snowpacks with two feet of snow or less are very weak and consist mainly of facets. I'd encourage her to break out her fatty skis, watch for rocks and have fun. The snowpack is just one big weak layer, but without a slab of snow it is relatively stable. I'd encourage her to watch last week's video clip showing this.

2. If mom was itching to go where the snow was deeper, like in the northern Gallatin Range, I would warn her about the weak snow near the ground and also about another layer near the surface. The one at the ground is our primary avalanche concern since it is still breaking clean in a few of our stability tests. Mark found this on Friday on his way to repair the Hyalite weather station and spoke about it in this video clip.

In the last seven days we dug pits on Mount Ellis, Flanders drainage, around Moonlight Basin, Bacon Rind, Taylor Fork, and West Yellowstone. Along with reports from ski patrols, we are finding a similar snowpack structure of weak snow at the ground with surface hoar and other facets buried a few inches deep by Wednesday and Thursday's snowfall (6-8 inches). Near Beehive Basin on Friday, skiers triggered a small avalanche on these facets that formed at the surface, our first human triggered slide in weeks. I'd warn mom about this too and also make double sure she had fresh batteries in her beacon and recently practiced with it. If we ever get big snows the avalanche danger will shoot through the roof and I'll want her to be on top of her game.

For today, the difference between a Moderate and Low avalanche danger is the difference between a slope having a slab of snow or not. Slopes with more than two feet of snow have a MODERATE Avalanche Danger, while those less than two feet thick have a LOW Avalanche Danger.

The mountains around Cooke City:

Eric and Mark are in Cooke City investigating the snowpack and found it deeper and stronger than any other range in our advisory area. They can still find weaker snow at the ground but concluded it would take a large load or finding a steep slope with an uncharacteristically shallow snowpack to trigger an avalanche. Without any signs of instability and snowpits indicating mostly stable conditions, for today the Avalanche Danger is rated MODERATE on all slopes steeper than 35 degrees and LOW Avalanche Danger elsewhere.

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.

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.

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.