Good Morning. This is Doug Chabot with an early season Avalanche Information Bulletin issued on Monday, November 15 at 7:30 a.m. This bulletin is sponsored by Montana Import Group in partnership with the Friends of the Avalanche Center. We will update this information tomorrow morning. For backcountry skiers, remember that uphill traffic is not allowed at Big Sky or Moonlight Basin Ski Areas and Bridger Bowl has backcountry snow conditions since they are not open.
After rock climbing in a t-shirt last weekend, my past two days of ice climbing has shredded any doubt that winter is here. A couple inches of snow fell Friday and Saturday night with much more in the last 24 hours. The Bridger Range got 4-6", the Hyalite area received 10-16"; the Big Sky area got 8-10"; West Yellowstone only received 3-4" and Cooke City got 7-10". Westerly winds are blowing 10-20 mph in the north, but reading 30-40 mph outside Cooke City. During the next 36 hours a wet, unstable weather system will continue to push into Montana from the northwest. Snowfall will increase tonight and continue into Tuesday. After a summer off I'm a bit rusty at predicting snowfall amounts, but I think we could see a foot by daybreak tomorrow.
Snowfall amounts are inconsistent because the freezing level is near 5,500', much higher than normal. Lower elevation measuring stations are showing a lot of moisture, but not much snow while higher sites are getting deeper snows. For example, both Hyalite Canyon and Carrot Basin SNOTEL sites got 10 inches of snow. But the Hyalite station at 8,000' received 1.5 inches of snow water (SWE) while Carrot at 9,000' only got half that water amount. Higher elevations have colder air which translates into more snow for a given amount of water. So expect glop at 8,000' and powder at 9,000'. This also means the higher elevations will have more snow than we're reporting. With wind speeds expected to drastically increase this afternoon and more snowfall in the next 36 hours, I expect avalanche activity will be peaking too.
Eric skied Bridger Bowl yesterday and dug a two foot deep snowpit, mostly solid. His main stability concern was density breaks in the newer snow, which is also what a skier up Hyalite found. A group of ice climbers on Sphinx Mountain showed good judgment and turned around with all the new snow falling and sluffing on the north face. This serious terrain of cliffs and gullies requires serious decisions, and they were rightly concerned with continued snowfall and increasing avalanche danger.
Reports from the Bridger, northern Gallatin and northern Madison Ranges indicate a solid base of dense snow at the ground-a nice change from last year. Even though I don't expect avalanches to break at the ground, I do expect them to break at the old snow surface and within the new snow from the rapid loading. Additionally, slopes near the ridgetop will have soft slabs from wind loading and be prone to slide. Continued snowfall and increasing winds today will only increase the instability.
Winter is here and avalanches are a reality. Treat the early season snows with respect no matter what you're activity. Avalanches don't discriminate--they catch skiers, climbers and hunters with equal gusto.
We will issue another Avalanche Information Bulletin tomorrow morning. If you have any snowpack or avalanche observations, drop us a line at mtavalanche@gmail.com or call us at 587-6984.
Upcoming Avalanche Education
TONIGHT at 7pm - 1 Hour Avalanche Awareness Class (Free) with the City of Bozeman Rec. Dept. at the Beall Park Rec. Center, Bozeman, MT. Located at 415 N Bozeman Ave. Topics covered include: avalanche terrain recognition, the affect weather has on avalanche hazard, the development of the mountain snowpack, decision making skills, and basic search and rescue procedures. Call 522-2290 for more info.
1 Hour Avalanche Awareness Class (Free) - Wed, November 17, 7:30pm - 8:30pm - Grizzly Outfitters, Big Sky, MT (more information)
1 Hour Avalanche Awareness Class (Free) -Thu, November 18, 6:30pm - 7:30pm - Basecamp, Billings, MT (more information)
Basic Avalanche Awareness - Wed & Thurs, December 1 & 2, 7:00pm - 9:30pm at SUB Ballroom B&C; 12/4- Field day at Bridger Bowl (more information) (PrePay $25 fee)
Avalanche Awareness for Snowmobilers - Wed & Thur, December 1 & 2, 7pm - 9:30pm at Team Bozeman, 2595 Simmental Way (more information)