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. Also, see the Avalanche Advisory posted below.

Today: Mostly cloudy. Snow in the morning...then chance of snow in the afternoon. Snow accumulation around 1 inch. Total snow accumulation 2 to 3 inches. Chance of snow 90 percent. Highs 19°F to 25°F.

Tonight: Partly cloudy. A 30 percent chance of snow in the evening. Lows 0°F to 6°F.

Wednesday: Partly cloudy. Highs 19°F to 25°F.

Wednesday Night: Mostly cloudy with scattered snow showers. Chance of snow 30 percent. Lows 5°F to 11°F.

Thursday: Mostly cloudy with a 30 percent chance of snow showers. Southwest winds around 15 mph in the afternoon. Highs 24°F to 30°F.

Thursday Night: Mostly cloudy with a 30 percent chance of snow showers. Lows 10°F to 16°F.

Friday: Partly cloudy with scattered snow showers. Chance of snow 30 percent. Highs 28°F to 34°F.

Friday Night: Partly cloudy. Lows 15°F to 21°F.

Saturday: Partly cloudy. Highs 34°F to 40°F.

Saturday Night: Partly cloudy. Isolated snow showers after midnight. Chance of snow 20 percent. Lows 18°F to 24°F.

Sunday: Cloudy with scattered snow showers. Chance of snow 50 percent. Highs 29°F to 35°F.

Sunday Night: Mostly cloudy with scattered snow showers. Chance of snow 50 percent. Lows 14°F to 20°F.

Monday: Mostly cloudy with scattered snow showers. Chance of snow 30 percent. Highs 22°F to 28°F.

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Mountain Weather

Last night snow showers dropped 4 to 5 inches in the Bridger Range and the Yellowstone Club while all other areas got 1 to 2 inches. Winds switched from southerly to westerly late yesterday with the arrival of a cold front. Currently ridgetop winds are averaging 15 to 20 mph out of the west with gusts of 30. The Bridger Range is windier with averages of 25 to 30 mph and gusts near 40. Mountain temperatures have dropped into the single digits Fahrenheit and will rise into the upper teens Fahrenheit by this afternoon. A few scattered showers this morning will give way to clearing skies as high pressure builds tonight.

Snowpack and Avalanche Discussion:

Gallatin and Madison Ranges, Lionhead Area near West Yellowstone, and Cooke City:

Wind slabs and buried weak layers are our two avalanche problems in southwest Montana (video). Yesterday my partner and I rode on Lionhead Ridge and watched the wind blow snow, feeding monstrous cornices. We stayed a healthy distance away from the ridgeline in case one of these overhanging chunks broke. Deeper in the snowpack a layer of facets buried 1.5 to 3 feet down is becoming harder to trigger. We dug four snowpits on different aspects and did stability tests in each one. All tests were taking a lot of force to initiate and propagate fractures on this layer. Furthermore, reports of collapsing and cracking (obvious red flags of instability) are decreasing. The faceted layers of concern vary, although their depth (less than three feet) is similar. Layers include:

• A very thin layer of facets on an ice crust,
• Feathery crystals of surface hoar,
• A layer of small facets up to a few inches thick,
• Thin snowpacks with their lower half consisting of sugary facets.

Although I like to geek out and identify these weak layers with my hand lens, in terms of assessing stability the grain type does not matter. If they break in stability tests or show red flag behavior, these slopes should be avoided. Since Friday these layers have been reliably found near Cooke City, up Hyalite canyon, in Taylor Fork, Hebgen Lake area and Lionhead; basically everywhere. Given the wind-loading and buried weak layers, it's still possible to trigger avalanches, thus the Avalanche Danger is rated MODERATE on all slopes today.

Bridger Range:

The Bridger Range received five inches of 8% density powder. Strong ridgetop and gusty mid-mountain winds will actively load and build slabs over a foot deep. These new born wind drifts will break easily, especially with human triggers. Wind speeds of 25-30 mph will act as Miracle-Gro for cornices and drifts at all elevations. A secondary avalanche concern is a layer of sugary, faceted snow buried 2-3 feet deep. On Saturday skiers triggered a small avalanche on this layer at Flathead Pass (photo). This slide appears to be similar to the one triggered on Bridger Peak last Tuesday (photo). This instability is not widespread, but dangerous nonetheless. For today the Avalanche Danger is CONSIDERABLE on all wind-loaded slopes in the Bridger Range. All other slopes have a MODERATE Avalanche Danger.

The next advisory tomorrow morning at 7:30 AM. 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.