Today...Breezy...cloudy. Slight chance of snow in the morning... Then chance of snow and rain in the afternoon. Highs 31°F to 37°F. Southwest winds 15 to 20 mph. Chance of precipitation 30 percent.

Tonight...Breezy. Chance of snow in the evening...then snow likely after midnight. Snow accumulation of 2 to 3 inches. Lows 19°F to 25°F. Southwest winds 15 to 25 mph. Chance of snow 60 percent.

Thursday...Breezy. Mostly cloudy. Chance of snow in the morning... Then chance of rain and snow in the afternoon. Highs 37°F to 43°F. Southwest winds 15 to 25 mph. Chance of precipitation 40 percent.

Thursday Night...Windy...snow. Snow accumulation of 2 to 4 inches. Lows 14°F to 20°F. Southwest winds 25 to 30 mph decreasing to 15 to 25 mph after midnight. Chance of snow 80 percent.

Friday...Breezy...colder...cloudy. Chance of snow in the morning... Then scattered snow showers in the afternoon. Highs 24°F to 30°F. West winds 15 to 20 mph. Chance of snow 50 percent.

Friday Night...Mostly cloudy with a 20 percent chance of snow. Lows 10°F to 16°F.

Saturday...Not as cold. Mostly cloudy with a 20 percent chance of snow. Highs 32°F to 38°F.

Saturday Night...Cloudy with a 30 percent chance of snow. Lows 14°F to 20°F.

Sunday...Mostly cloudy with a 20 percent chance of snow. Highs 32°F to 38°F.

Sunday Night...Partly cloudy with a 20 percent chance of snow. Lows 12°F to 18°F.

Monday...Mostly cloudy. Chance of snow in the morning...then chance of snow and rain in the afternoon. Highs 31°F to 37°F. Chance of precipitation 40 percent.

Monday Night...Mostly cloudy with a 40 percent chance of snow. Lows 14°F to 20°F.

Tuesday...Mostly cloudy with a 20 percent chance of snow. Highs 30°F to 36°F.

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

Mountain Weather

Lingering showers yesterday morning and a bit more last night accumulated five inches near Big Sky, and two to three inches everywhere else. West winds increased at the ridge tops and have averaged 25-30 mph with gusts to 40 mph. Temperatures are currently in the low teens after reaching the mid 20s Fahrenheit yesterday. Later today, mostly sunny skies will cloud over as mountain temperatures rise into the low 30s Fahrenheit and winds blow west to southwest at 25-35 mph. A trace to one inch of snow may fall in the southern mountains tonight, but a dry high pressure ridge is keeping significant snowfall at bay.

Snowpack and Avalanche Discussion:

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

Today's avalanche forecasting challenge is an easy one and can be summed up in two words: wind-loading. Yesterday were the first strong winds that blew since the weekend's snow. Low density powder covered the mountains from a depth of six inches up north to twenty inches around Cooke City. Yesterday, by early afternoon, soft slab avalanches were releasing naturally near the ridgelines. This was witnessed by the ski patrols around Lone Mountain as well as Mark and another party in the northern Bridger Range.

Mark toured above Fairy Lake and to the Great One on Sacajewea. The winds were moving impressive amounts of snow near the ridge top. Winds also swirled mid mountain and formed thin slabs that easily cracked on the lower density snow underlying it. Mark's snowpits confirmed that instabilities were limited to the new windblown snow. A skier the day before found feathery, weak crystals of surface hoar immediately north of Bridger Bowl (now buried under the new snow), but Mark did not find it. Small grains of faceted snow were also seen near Big Sky and Cooke City. None of these layers seem widespread, but they're worth knowing about since wind slabs will pop even easier on them. Eric and I investigated a slide on Sunday in the southern Madison Range with this recipe. Thick, hard, wind slabs avalanched on a thin layer of facets when a skier knocked a cornice off triggering the slope.

Within a few hours of the winds starting to blow yesterday, small natural avalanches were seen. Since then, the winds have continued blowing at a steady clip which has only increased the likelihood of avalanches. Cornices will be sensitive to breaking and wind slabs will be easily triggered.

For today, all wind-loaded slopes have a CONSIDERABLE Avalanche Danger. Slopes not affected by the wind will have great powder and a LOW Avalanche Danger.

PHOTOS, SNOWPITS, VIDEO and SURVEY RESULTS

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.

3. The results from our survey are posted online. Thanks to all who participated. You can check out the results at http://bit.ly/fpLuSi.

In response to our survey we added a new page to the website with images of our snowpit profiles. This page is under the Resources/Other Info tab at http://fsavalanche.org/Encyclopedia/snowpit.htm

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.