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: Mostly cloudy in the morning then clearing. Occasional flurries in the morning. Highs 17°F to 23°F.

Tonight: Mostly clear. Patchy fog after midnight. Lows -4°F to 6°F.

Thursday: Mostly sunny. Patchy fog in the morning. Highs 22°F to 28°F.

Thursday Night: Mostly clear. Patchy fog after midnight. Lows -3°F to 7°F.

Friday: Mostly sunny. Patchy fog in the morning. Highs 22°F to 28°F.

Friday Night: Mostly clear. Patchy fog after midnight. Lows 0°F to 10°F.

Saturday: Mostly sunny. Patchy fog in the morning. Highs 24°F to 30°F.

Saturday Night: Mostly clear in the evening then becoming partly cloudy. Patchy fog after midnight. Lows 0°F to 10°F.

Sunday: Partly cloudy. Highs 23°F to 29°F.

Sunday Night: Partly cloudy. Lows 1°F to 9°F.

Monday / Martin Luther King Jr Day: Partly cloudy. Highs 21°F to 27°F.

Monday Night / Martin Luther King Jr Night: Partly cloudy in the evening then clearing. Patchy fog after midnight. Lows 2°F to 10°F.

Tuesday: Mostly sunny. Patchy fog in the morning. Highs 22°F to 28°F.

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

Mountain Weather

Early yesterday morning another inch fell around Big Sky before clouds lifted and high pressure moved in. Temperatures this morning are in the teens Fahrenheit up north and single digits Fahrenheit in the southern ranges. West to northwest winds have been blowing 35 to 50 mph in the Bridger Range and up Hyalite Canyon, but are 15 to 30 mph elsewhere. Today will be mostly sunny with mountain temperatures reaching the low twenties Fahrenheit as westerly winds weaken to 15 to 25 mph. No new snow is expected for the next several days.

Snowpack and Avalanche Discussion:

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

Winds picked up yesterday with plenty of snow to move around. Not all wind-loading was at the ridgelines. Mid and lower mountain winds were reported moving lots of snow too. The winds both give and take. On the take side, a skier found deeply scoured slopes in Montagne's Meadow north of Bridger Bowl (photo). Scoured slopes are safe, but certainly no fun. On the give side of things, a skier in the northern Madison Range yesterday found multiple slopes with soft slabs of wind-blown snow. He triggered a small slide 20 feet across and 15 inches deep which ran a couple hundred feet downhill on a slope of only 30 to 33 degrees. Other signs of instability were cracks shooting 30 feet out from his skis and a "whumph" of the snowpack. It will be easy to trigger avalanches on wind drifts throughout our advisory area, especially since winds were pluming snow around Cooke City and in Hyalite too.

Buried under the top 6 to 16 inches of snow is a weak layer (photo). In most areas this layer is small-grained facets which look and feels like tiny grains of sugar. They do not stick together and with enough snow load, they will fracture. I discovered this in stability tests near West Yellowstone on Monday (video). A few slopes have feathery surface hoar crystals buried instead. The crystal type doesn't matter, just its potential to fracture under the weight of new or wind-blown snow. The weak snow is not evenly distributed throughout southwest Montana. Some slopes have it, some do not. Lucky for us it's so close to the surface even the laziest among us can find it with a quick hand pit or swipe of a shovel. This is the layer that likely caused the collapsing in the northern Madison Range yesterday as well as allows cracks to propagate.

For today, all slopes that are wind-loaded have a CONSIDERABLE Avalanche Danger. Slopes without a wind-load are rated 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.

EDUCATION, PHOTOS, SNOWPITS, and VIDEOS

1. For links to Articles, Education and (photos) and (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.