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 / New Years Day: Partly cloudy. Highs 12°F to 18°F. * Happy New Year *

Tonight / New Years Night: Partly cloudy. Scattered flurries through the night. Lows -3°F to -9°F. * Happy New Year *

Wednesday: Partly cloudy in the morning then clearing. Highs 15°F to 2°F1. Lowest wind chill readings -11°F to -21°F in the morning.

Wednesday Night: Mostly clear. Patchy fog after midnight. Lows -6°F to 2°F.

Thursday: Not as cold. Mostly sunny. Patchy fog in the morning. Highs 23°F to 29°F.

Thursday Night: Mostly clear. Lows 1°F to 7°F.

Friday: Mostly sunny. Highs 19°F to 25°F.

Friday Night: Mostly clear. Lows -1°F to 5°F.

Saturday: Mostly sunny. Highs 23°F to 29°F.

Saturday Night: Mostly clear. Lows 1°F to 7°F.

Sunday: Partly cloudy with a 20 percent chance of snow. Highs 22°F to 28°F.

Sunday Night: Partly cloudy with a 20 percent chance of snow. Lows 4°F to 10°F.

Monday: Partly cloudy with a 20 percent chance of snow. Highs 21°F to 27°F.

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

Mountain Weather

In the last 24 hours a trace to one inch of snow has fallen with light winds out of the northwest. Temperatures this morning are 5 to 10 degrees Fahrenheit under mostly cloudy skies. Today, temperatures will warm into the teens Fahrenheit as skies begin to clear. A few flurries will dust slopes as winds continue to blow northwest at 10 to 20 mph. Sunny skies are on the docket for the rest of the week.

Snowpack and Avalanche Discussion:

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

In order to make good decisions regarding avalanches in the backcountry, there are two questions Mark, Eric and I routinely ask ourselves: What do we know? What should we do about it?

  What do we know?

We know that most mountain ranges are generally stable except on individual slopes with a snowpack thinner than three feet deep. These shallow slopes have weak, poorly-bonded faceted grains near the ground that can still avalanche. As evidence, I saw a natural slide on Sunday on Lionhead Ridge (photo) and Eric found a snowmobiler triggered avalanche outside Cooke City on Friday (photo, video). Some other slopes consist entirely of weaker, unbonded facets, but are stable without the burden of new snow. Yesterday, Karl found this on Mount Ellis and Mark found a similar structure on Mount Blackmore.

  What should we do about it?

At a minimum we need to probe to check how deep the snow is. If we find three feet or less, it's a good idea to dig and test the snow. I recommend digging all the time, but if you're lazy and slightly hungover today, at least dig where it's thin. On Sunday, I found a thin slope and did stability tests in multiple pits. This particular slope did not have facets, so we rode on it. Yesterday, on a day off, Mark found stable conditions on Mount Blackmore and skied committing lines. Conversely, to the south near Hebgen Lake on the day after Christmas, Eric found a three foot deep snowpack with facets breaking clean in his tests so he stayed off steeper slopes. Digging allows us to quickly look at the snow structure and determine if there are weaker, granular layers trying to support a denser slab. We recognize this as a poor structure and it deserves a few stability tests.

For today, slopes steeper than 35 degrees will have a MODERATE Avalanche Danger. Lower-angled terrain has a LOW Avalanche Danger.

  Looking to the future

The top 6 to 12 inches of snow is changing. Cold, clear nights and sunny days signal large fluctuations in the radiation balance which quickly turn snowflakes into weak, poorly-bonded facets and/or promote the growth of feathery surface hoar crystals. This surface snow may become a future weak layer once it gets buried. The formation of these crystals began right before Christmas and will continue this week. A skier in Beehive Basin on Sunday noted small avalanches, 20 to 40 feet wide, breaking a few inches deep, likely on this layer. We'll be keeping an eye on it and so should you.

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 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.