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.

Today: Breezy. Partly cloudy. Southwest winds 15 to 20 mph. Highs 14°F to 20°F. Lowest wind chill readings -24°F to -34°F in the morning.

Tonight: Breezy. Partly cloudy. West winds 15 to 20 mph. Lows 3°F to 9°F.

Friday: Not as cold. Partly cloudy. Scattered flurries in the afternoon. South winds around 15 mph. Highs 23°F to 29°F.

Friday Night: Partly cloudy. Scattered flurries in the evening. Southwest winds around 15 mph in the evening. Lows 7°F to 13°F.

Saturday: Partly cloudy in the morning then becoming mostly cloudy. Scattered flurries through the day. Highs 24°F to 30°F.

Saturday Night: Mostly cloudy. Slight chance of snow in the evening...then chance of snow after midnight. Chance of snow 40 percent. Lows 13°F to 19°F.

Sunday: Breezy. Mostly cloudy with a 50 percent chance of snow. Highs 19°F to 25°F.

Sunday Night: Mostly cloudy with a 50 percent chance of snow. Lows 9°F to 15°F.

Monday: Mostly cloudy with a 50 percent chance of snow. Highs 19°F to 25°F.

Monday Night: Mostly cloudy with a 50 percent chance of snow. Lows 4°F to 10°F.

Christmas Day / Tuesday: Partly cloudy with a 20 percent chance of snow. Highs 14°F to 20°F. * Merry Christmas *

Christmas Night / Tuesday Night: Colder. Partly cloudy with a 20 percent chance of snow. Lows -5°F to 1°F. * Merry Christmas *

Wednesday: Partly cloudy. Highs 17 to 23.

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

Mountain Weather

This morning temperatures were in the single digits Fahrenheit and ridgetop winds were blowing 15 to 20 mph from the West and Southwest with gusts of 30 mph. Major low pressure systems are impacting the west coast and the Midwest, but southwest Montana remains under a ridge of high pressure. Fortunately this ridge will flatten and move east this weekend. Today temperatures will climb into the teens Fahrenheit, and winds will increase and blow 25 to 40 mph from the Southwest.

Snowpack and Avalanche Discussion:

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

Yesterday's winds transported some of the last remaining snow off ridgetops onto leeward slopes (photo). While this wind-blown snow will not alter the avalanche danger, it will remain the primary avalanche problem (example from Cooke City and the Bridger Range). Wind slabs will be tricky today because many will be stubborn and difficult to trigger. I have been fooled many times by wind slabs when some do not crack and move on small test slopes while others produce avalanches.

A secondary avalanche problem is a persistent weak layer of faceted snow within the bottom 1.5 feet of the snowpack. This layer has both gained strength and adjusted to the weight of new snow from the last two weeks. We have not seen, nor heard reports of recent signs of instability on this layer other than results from ski area explosives. One exception is the west side of the Bridger Range where a weak snowpack and some collapsing was observed three days ago. Yesterday Karl and Doug investigated the snowpack on Saddle Peak where they found greatly improved stability test results in this faceted snow layer compared to what Doug and Eric found 10 days ago (previous snowpit vs current snowpit). However, wind slabs at the top of their snowpit easily fractured.

Wind slabs that can be triggered by a skier or rider combined with slopes harboring some weak snow near the ground mean it's still possible to trigger an avalanche today. For this reason the Avalanche Danger is rated MODERATE.

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. For links to all photos and videos listed in the above report, please visit this Link.

2. We've recently uploaded more photos and snowpits to our web site, more than what are linked in the advisory.

3. 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.