GNFAC Avalanche Advisory for Wed Jan 25, 2017

Not the Current Forecast

Good Morning. This is Doug Chabot with the Gallatin National Forest Avalanche Advisory issued on Wednesday, January 25th at 7:00 a.m. Today’s advisory is sponsored by Yellowstone Arctic Yamaha and Yamaha Motor Corp in cooperation with the Friends of the Avalanche Center.  This advisory does not apply to operating ski areas.

Mountain Weather

There’s no new snow to report, just cold temperatures. At 5 a.m. temperatures are in the low single digits under partly cloudy skies. Winds are light out of the N-NW at 5-10 mph. Today, temperatures will reach the upper teens with ridgetop winds blowing lightly from the north. Clouds will increase later this afternoon and an inch of snow may fall tonight. Tomorrow we get fed another serving of high pressure bringing sunny skies and dry weather through the weekend.

Snowpack and Avalanche Discussion

Madison Range   Southern Gallatin Range   Lionhead area near West Yellowstone   Cooke City

Yesterday my partner and I rode Taylor Fork and skied in Lightning Creek in the southern Madison Range. Our first two pits showed good stability even though the facets at the ground were sugary and weak. This matches findings from our previous field days showing the snowpack trending toward safe conditions. While this observation is true, we also know there are a few slopes where this is false and the snowpack is unstable.  Yesterday I found one of those slopes. Although I was feeling confident about the stability, as a precaution I stopped, dug, and performed a few tests before skiing the steep slope below me, and it’s a good thing I did. My 4 tests all propagated fractures on depth hoar at the ground indicating instability (video, photo, snowpit profile). I was shocked, and we skied our low-angled skin track back to the sleds. This was a tangible example of Moderate avalanche danger: many stable slopes, but a few unstable ones hidden in plain sight. Dig and test, there’s no other way to know what’s under your feet.

Besides the weak layer at the ground, there’s another one 2-3 feet under the surface and yet a third recently buried under a couple inches of snow: feathery surface hoar crystals (photo). The layer at the ground is widespread, the other two are not. The surface hoar isn’t buried deep enough to be a problem yet, and the mid-pack layer of facets is spotty and requires a stability test to locate. For today, the avalanche danger continues to be MODERATE since it is still possible to trigger an avalanche.

Bridger Range   Northern Gallatin Range

The Bridger Range and northern Gallatin Range have good stability. In the last 2 days only a trace to an inch of snow fell in the Bridger Range, while the higher elevations of Hyalite got a 4+” of low density powder. Winds have been light and there has not been enough loading to increase the avalanche danger. Yesterday a skier up Hyalite noticed a couple of big cornices broke off the ridge yet did not trigger an avalanche; good evidence of stability. For today, the avalanche danger is rated LOW.  

Eric will issue the next advisory tomorrow morning by 7:30 a.m.

We rely on your field observations. Send us an email with simple weather and snowpack information along the lines of what you might share with your friends: How much new snow? Was the skiing/riding any good? Did you see any avalanches or signs of instability? Was snow blowing at the ridgelines? If you have snowpit or test data we'll take that too, but this core info is super helpful! Email us at mtavalanche@gmail.com or leave a message at 406-587-6984.

Upcoming Events and Education

Month of January: Montana Ale Works has chosen the Friends of the Avalanche Center as January's "Round It Up America" recipient. Every time you round-up your bill the change gets donated to the Friends. Pennies equal dollars!

King and Queen of the Ridge, Saturday, February 4th. A Hike and Ski/Ride-a-Thon fundraising event to support the Friends of the Gallatin National Forest Avalanche Center. Register with Bridger Bowl HERE, make pledges HERE.

Beacon Training Park at Beall: Open and free to the public for avalanche beacon practice seven days a week from 9 a.m. to 8 p.m., southeast corner of Beall Park in Bozeman.

COOKE CITY

Weekly rescue training and snowpack update, 6-7:30 p.m., The Antlers Lodge on Friday, field location Saturday TBA.

DILLON

February 4 and 5, Intro to Avalanches with Field Day, More info and sign up HERE.

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