GNFAC Avalanche Advisory for Tue Jan 26, 2016

Not the Current Forecast

Good morning. This is Doug Chabot with the Gallatin National Forest Avalanche Advisory issued on Tuesday, January 26, at 7:00 AM. Today’s advisory is sponsored by Soda Butte Lodge and Bountiful Table. This advisory does not apply to operating ski areas.


SOMBER NEWS

In the last 10 days 10 people have died in avalanches in the US, two in Montana. Avalanches are equal opportunity killers and since last Tuesday experts, novices, skiers and snowmobilers have died. Let that sink in over your morning coffee. More information can be found at CAIC.


Mountain Weather

There’s been no new snow in the last 24 hours, just wind. Blowing west, speeds are strongest in the northern mountains, averaging 35 mph with gusts in the 40s. In Taylor Fork, West Yellowstone and Cooke City winds are westerly and averaging 10-15 mph with gusts of 20. At 5 a.m. under clear skies temperatures are in the low teens, but 1F at Lulu Pass outside Cooke City. Temperatures will warm into the 20s and high clouds will roll in later this afternoon, but no snow is expected.


Snowpack and Avalanche Discussion

Bridger Range   Northern Madison Range   Northern Gallatin Range

By sunup yesterday the northern mountains received 5 inches of low density snow at Bridger Bowl and 10-14 inches in Hyalite and Big Sky, perfect fodder for wind-loading.  Wind speeds are on the rise and formed many wind slabs at all elevations last night. These soft slabs of windblown snow could be a couple feet thick and easily triggered. Additionally, cornices are growing from these winds and will be sensitive to breaking and triggering slides (photo).

Besides avoiding wind slabs there are two weak layers to dig for and test. Small facets buried 1-2 feet under the surface and large facets (depth hoar) near the ground. Over the last week avalanches have occurred on both…a near miss in Frazier Basin (photo), a fatality in Cedar Basin (report) and a snowmobiler triggered slide in Buck Ridge (photo).

Given the recent snow, wind and avalanche activity, the avalanche danger is rated CONSIDERABLE on all wind-loaded slopes and MODERATE on all others.


Southern Madison Range   Southern Gallatin Range  

Lionhead area near West Yellowstone   Cooke City

The southern mountains have lingering instability with two layers of facets breaking and avalanching. A slide was triggered in Cabin Creek in the southern Madison Range (photo) on Thursday and near Daisy Pass outside Cooke City on Saturday.  These weak layers are the same ones found in the northern ranges: depth hoar near the ground and small facets 1-2 feet under the surface.  Eric was in Bacon Rind on Sunday and found both, which he describes in this video. It’s notable that the layer at the ground has not gained strength in the 11 days since his last visit.

For today, given that human triggered avalanches are still possible, the avalanche danger is rated MODERATE. The likelihood of triggering avalanches has decreased, but my confidence is low. Depth hoar has fooled me before and killed a professional ski patroller last week. I’m being extra careful and staying off steep, exposed terrain.


I will issue the next advisory tomorrow morning by 7:30 a.m. If you have any snowpack or avalanche observations to share, drop us a line at mtavalanche@gmail.com or leave a message at 587-6984.


EVENTS and AVALANCHE EDUCATION

A complete calendar of classes can be found HERE.

TOMORROW: Advanced Avalanche Workshop w/ Field Course

January 27, 28, and 30: https://www.ticketriver.com/event/16862

Course content includes: snowpack metamorphism, the mechanics of avalanche failure and fracture, and decision-making. Different topics are covered each evening session. The field session includes snowpack analysis and avalanche rescue scenarios.

West Yellowstone: Saturday, January 30, 1hr Avalanche Awareness, West Yellowstone Holiday Inn, 7-8:30 p.m.

Cooke City: Saturday, January 30, Companion Rescue Clinic for Snowmobilers.  Information and registration here: https://www.ticketriver.com/event/18078

Lewistown: Saturday, January 30, 9:00 a.m., 1hr Avalanche Awareness for Snowmobilers, Lewiston Honda-Polaris.  More information can be found HERE.

EVENT at BRIDGER BOWL: February 6, King and Queen of the Ridge. A day of hiking and skiing the Ridge as a fundraiser for the Friends of the Avalanche Center.  Teams and individuals are welcome! More info here: http://bridgerbowl.com/event/king-and-queen-of-the-ridge