GNFAC Avalanche Advisory for Sun Jan 24, 2016

Not the Current Forecast

Good morning. This is Doug Chabot with the Gallatin National Forest Avalanche Advisory issued on Sunday, January 24, at 7:00 AM. Today’s advisory is sponsored by Javaman and Alpine Orthopedics. This advisory does not apply to operating ski areas.


Mountain Weather

The mountains picked up a trace to one inch of new snow this morning.  Temperatures are in the high teens to low 20s and winds are averaging 10-15 mph out of the west with gusts of 20-25. Light snowfall will continue today and tonight with accumulations of 1-2 inches by morning. Winds will remain moderate from the west and temperatures will rise into the high 20s this afternoon.


Snowpack and Avalanche Discussion

Bridger Range   Madison Range   Gallatin Range  

Lionhead area near West Yellowstone   Cooke City

Winds have lessened in the past 36 hours and so has the wind-loading. In the absence of significant new snow and wind, triggering slides is more difficult than it was a couple days ago, but by no means impossible. In the last five days skiers and snowmobilers have triggered avalanches while natural slides have occurred on wind-loaded slopes.

  • Yesterday, two skiers had a cornice break which triggered a slide to the north of Baldy Peak in the Bridger Range (photo). It was estimated to be two feet deep running 700 feet down slope.
  • Yesterday, natural avalanches were seen on Sheep Mountain outside Cooke City on wind-loaded slopes.
  • On Friday, a snowmobiler triggered a deep avalanche in the 3rd Yellowmule on Buck Ridge in the northern Madison Range (photo). It failed on depth hoar.
  • On Thursday, snowmobilers triggered a small slide in Cabin Creek in the southern Madison Range (photo) while two skiers were caught and lost gear in a slide on the west side of the Bridger Range in Truman Gulch as they skinned uphill.
  • On Tuesday, a Yellowstone Club ski patroller died in an avalanche outside the YC Ski Resort boundary in a slide on a steep, wind-loaded slope (video, photo).This same day skiers triggered a large slide in Frazier Basin in the Bridger Range (photo), but no one was caught.

We have two layers of concern: depth hoar at the ground and small-grained facets 1-2 feet under the surface (explained in this video).  With snowfall waning natural avalanches will be absent and there will be no signs of instability until you trigger a slide, which is too late. The easiest way to remain safe is to avoid avalanche terrain.  If that’s not your cup of tea, then you should make an informed decision about skiing or riding a slope which requires digging and testing what’s under your feet, but even this is not foolproof. I cannot condone hitting big exposed slopes or even smaller steep ones at the moment; the risk is too high for my tolerance.

The avalanche danger today is rated MODERATE, and a scary one at that, since the potential to trigger slides is there, but the warning signs are not.


Eric 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.


BEACON PARK IS OPEN 7 DAYS A WEEK (9 a.m. to 8 p.m) at BEALL PARK, BOZEMAN and WEST YELLOWSTONE.

The Friends of the Avalanche Center and Bozeman Parks and Rec installed a Beacon Park at Beall Park while the USFS Snow Rangers installed one on the main trail to Two Top out of West Yellowstone. It is a great way to practice searching for single and multiple beacons. 


EVENTS and AVALANCHE EDUCATION

A complete calendar of classes can be found HERE.

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.

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.

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