Today...Mostly cloudy. Snow likely in the morning...then chance of snow in the afternoon. Snow accumulation of 1 to 2 inches. Total snow accumulation 2 to 6 inches. Highs 16°F to 22°F. Chance of snow 70 percent. Lowest wind chill readings -13°F to -23°F early in the afternoon.

Tonight...Partly cloudy with a 20 percent chance of snow. Lows -7°F to 1°F.

Thursday...Breezy. Mostly cloudy. A 20 percent chance of snow in the afternoon. Highs 16°F to 22°F. Southwest winds 15 to 20 mph in the late morning and afternoon.

Thursday Night...Breezy. Not as cold. Mostly cloudy with a 40 percent chance of snow. Lows 10°F to 16°F. Southwest winds 15 to 20 mph.

Friday...Not as cold. Mostly cloudy with a 40 percent chance of snow. Highs 24°F to 30°F. Southwest winds around 15 mph.

Friday Night...Snow. Moderate snow accumulations. Lows 14°F to 20°F. Chance of snow 90 percent.

Saturday...Snow likely. Moderate snow accumulations. Highs 24°F to 30°F. Chance of snow 70 percent.

Saturday Night...Mostly cloudy in the evening then becoming partly cloudy. A 20 percent chance of snow. Lows 8°F to 14°F.

Sunday...Mostly cloudy with a 20 percent chance of snow. Highs 21°F to 27°F.

Sunday Night...Mostly cloudy with a 30 percent chance of snow. Lows 9°F to 15°F.

Monday...Partly cloudy with a 30 percent chance of snow. Highs 21°F to 27°F.

Monday Night...Partly cloudy with a 20 percent chance of snow. Lows 7°F to 13°F.

Tuesday...Mostly cloudy with a 40 percent chance of snow. Highs 25°F to 31°F.

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Mountain Weather

Last night's 6-9 inches around Big Sky and 11 inches at Bridger Bowl fell with barely a whisper of wind. Cooke City picked up an additional five inches with the southern Madison Range getting only 2 inches. Ridgetop winds have been blowing 5-10 mph out of the northwest as temperatures dropped to near 10°F. This storm will give us another inch or two before leaving this morning. Clouds will decrease throughout the afternoon and temperatures will rise into the high teens as winds increase out of the west to 15-20 mph.

Snowpack and Avalanche Discussion:

The mountains around Cooke City and the Washburn Range:

The mountains around Cooke City have gotten 2-3 feet of settled snow since Saturday night (3 inches Snow Water Equivalent). Winds blew out of the west to northwest during most of the storm. Mark and a partner checked on stability yesterday and had to keep their throttles pinned to chew a track through all the new snow. They rode around Lulu and Daisy Passes and only saw a few avalanches that were confined to wind-blown snow in steep, rocky areas. Given the huge load that these mountains were faced with, he was pleasantly surprised at the isolated activity. His snowpits indicated a strong snowpack.

Three inches of snow water equivalency is a lot of weight to support, even for a strong snowpack. These mountains will need a few days without snowfall to fully adjust to the load. Winds on Sunday and Monday heavily drifted snow at all elevations.

For today, the Avalanche Danger is rated CONSIDERABLE on all wind-loaded slopes. Slopes steeper than 35 degrees also have CONSIDERABLE Avalanche Danger while all other terrain has a MODERATE Avalanche Danger.

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

Last night's 6-9 inches from Big Sky to the Bridger Range's 11 inches fell as 6-7% density powder with winds so calm I had to check the data twice to really believe it. Before this storm, winds blew 20-30 mph out of the west loading many slopes. We are finding that the snowpack, in general, is lacking widespread weak layers and can handle the 12-16 inches of snow that fell since Saturday night. Our main stability concern is on slopes that got wind-loaded the past few days, and also on terrain that has a thinner, more faceted snowpack. Gallatin National Forest Snow Rangers saw a slide on Cedar Mountain in the northern Madison Range yesterday that broke on a rocky rollover.

My partners and I skied down the west side of the Bridger Range yesterday and found weak, sugary snow on west to southwest aspects where the depth was only a meter deep. This mirrored what I saw in Beehive Basin on Sunday. In both pits I was unpleasantly surprised at how easily these facets fractured. The Big Sky Ski Patrol triggered a slope on the south face of Lone Peak with explosives that also failed on facets that had gotten weaker. Slopes with underlying facets are isolated and easy to ferret out. If you poke a ski pole to the ground or sink to your crotch when stepping off a sled, you found it. These slopes, as well as slopes with wind loads, are where avalanches can be triggered from.

For today, the Avalanche Danger is rated CONSIDERABLE on all wind-loaded slopes. All other terrain has a MODERATE Avalanche Danger.

Information provided by Doug Chabot, Mark Staples, and Eric Knoff from the Gallatin National Forest Avalanche Center.

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.