Archived Advisory for Tue Jan 15 2008

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Tuesday, January 15th, 2008

Good morning. This is Scott Schmidt with the Gallatin National Forest Avalanche Advisory issued on Tuesday, January 15th, at 7:30 a.m. Team Bozeman and Yamaha, in cooperation with the Friends of the Avalanche Center, sponsor today’s advisory. This advisory does not apply to operating ski areas.

MOUNTAIN WEATHER

The blustery frontal system that pushed through our area last night brought lots of wind but no new snow to the mountains of southwest Montana. Ridge top winds have been 25 – 45 mph from the west for the past 12 hours, and mountain temperatures are in the mid-teens this morning.

Skies will be cloudy today as moisture moves into our area on a northwest flow. Winds will blow 20 – 40 mph at the ridgelines, and temperatures will be in the low teens at 9000 feet. There is a lot of atmospheric instability associated with this weather disturbance so expect wind conditions at all elevations in the mountains today. Mountain snow showers will develop this morning, depositing 3 – 6 inches in the mountains by tonight. This storm pattern has all the ingredients to produce a little “northwest flow magic” in the Bridger Range. You never know what could happen when magic is involved. We’ll just have to wait and see.

SNOWPACK AND AVALANCHE DISCUSSION

The Bridger Range:

The Bridger Bowl ski patrol reported small wind slabs that formed from strong southerly winds yesterday. These wind slabs ski cut easily but were small and did not present a significant avalanche danger. We’ve had two reports of surface hoar on north-facing slopes in the northern Bridger Range. Yesterday’s wind blown snow loaded north-facing aspects may have created isolated pockets of instability on slopes where this surface hoar exists. Investigate the snowpack on all north-facing terrain before traveling on it today. The avalanche danger in the Bridger Range is CONSIDERABLE on all recently wind-loaded slopes steeper then 35 degrees. Wind-loaded slopes that are less steep have a MODERATE danger. Non-wind-loaded slopes in these mountains have a LOW danger.

The northern Gallatin Range and northern Madison Range:

The Moonlight Basin patrol reported a natural avalanche that released on Fan Mountain yesterday. The avalanche released on a wind-loaded slope and ran approximately 2000 vertical feet. Mark Staples went into Wyoming Bowl (just outside of the Big Sky boundary) to look at the remotely triggered slide we reported yesterday. On his way down to the fracture he triggered another small avalanche on a wind-loaded slope. Both of these avalanches released on slopes with a southerly aspect and a thin snowpack, running on faceted snow sitting 8 – 10 inches above the ground. The interesting thing is that both avalanches released on slopes that were less steep the 35 degrees. Doug and I found these same well developed facets on a north-facing slope in the Portal Creek drainage when we investigated an avalanche burial that occurred Saturday. You can see a video clip of the stability test on this layer at:

http://www.youtube.com/watch?v=EngZ4RQEyZQ&feature=PlayList&p=1ECB29D405CEF2C6&index=0

Today, the avalanche danger in the northern Gallatin and northern Madison Ranges is CONSIDERABLE on all slopes that have been loaded by winds. A MODERATE danger exists on all non-wind-loaded slopes.

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

Doug was in the mountains near Cooke City yesterday. He and partner found good stability on most slopes they investigated. They still got clean shears on the layer of faceted snow, buried 1 foot above the ground on south-facing slopes, and they saw a recent avalanche that had released on this layer within the past 24 – 48 hours. There is a picture of this slide at

www.mtavalanche.com/photos/photos.php

With lots of new snow available for transport in the southern mountains, today’s strong winds will continue to loaded lee facing slopes and the avalanche danger in the southern Madison and southern Gallatin Ranges, the Lionhead area near West Yellowstone, the mountains around Cooke City, and the Washburn Range, remains CONSIDERABLE on wind-loaded slopes steeper then 35 degrees. Wind-loaded slopes that are less steep, and all non-wind-loaded slopes have a MODERATE danger.

FOUND BACKPACK

I would like to extend my thanks to Connie Cusick of West Yellowstone who picked up my backpack from the parking area at Targhee Pass on Saturday. Thanks Connie for saving me from another of my many senior moments. I really appreciate it.

AVALANCHE EDUCATION

The Friends of the Avalanche Center will present a one hour avalanche awareness lecture Tonight, January 15, 2008 at the Bozeman Public Library. This presentation starts at 7:00 p.m. and is sponsored by the Montana Outdoor Science School. Contact them at 406-582-0526 for more information.

The Friends of the Avalanche Center will present a one hour avalanche awareness lecture for snowmobilers on Wednesday, January 16, 2008 at Redline Sports, 2050 Harrison Ave., Butte, MT. This presentation starts at 6:00 p.m. Contact Redline Sports at 406-782-9129 for more information.

The Friends of the Avalanche Center will present a one hour avalanche awareness lecture for snowmobilers on Wednesday, January 16, 2008 at the Billings Public Library. This presentation starts at 7:00 p.m. and is sponsored by Yellowstone Polaris. Contact them at 406-259-7777 for more information.

Big Sky Snow Safety Director Scotty Savage, and Ron Johnson of the Avalanche Center will present a two hour avalanche awareness lecture relating to the terrain that can be accessed from the Big Sky backcountry gates. The presentation will be held in the amphitheater in the Huntley Lodge at Big Sky from 6:00 to 8:00 pm, Wednesday, January 16th. Contact the Avalanche Center at 406-587-6984 for more information.

The Gallatin National Forest Avalanche Center will present a 2 day avalanche awareness seminar for snowmobilers on Saturday and Sunday, January 19-20, 2008. Saturday’s session will be held at Pond’s Lodge from noon to 4:30 p.m. Sunday’s field session will be from 9:00 a.m. to 3:00 p.m. Information about Sunday’s session will be given during Saturday’s classroom session. Contact the Avalanche Center at 587-6984 for more information.

Angela Patnode will present a free 1-hour Avalanche Awareness Class for women at 7:00pm at the Bozeman Public Library in the small conference room on Tuesday, January 29th. This class is sponsored by Bozeman-based Team WinS (Women in Sports). For more information visit www.teamwins.org.

Doug will issue the next advisory tomorrow morning at 7:30 a.m. If you get out in the backcountry give us a call or email with your observations. You can reach us at 587-6984 or email us at mtavalanche@gmail.com .