Good morning. This is Doug Chabot with avalanche and weather information from the Gallatin National Forest Avalanche Center on Monday, December 4th, at 7:30 a.m. This information is sponsored by Yellowstone Club Community Foundation and Basecamp Gallatin and Yamaha. We will update this information as conditions change.
Since yesterday morning the mountains got 3” of snow near Cooke City, West Yellowstone and Island Park with 1-2” near Bozeman and Big Sky. Wind has been out of the west at 15-30 mph with gusts of 40-60 mph. Temperatures are 20s to low 30s F this morning. Today, temperatures will reach mid-30s F, wind will be out of the west at 15-25 mph with gusts to 45 mph, and 1-2” of snow is possible. The next couple days will be partly cloudy to mostly sunny with daytime temperatures reaching mid-30s to low 40s F and overnight temperatures in the mid-20s F. Colder temperatures and snow are expected late Wednesday night through next weekend.
While Dave and his partner were digging a pit on Lionhead Ridge yesterday, unbeknownst to him, a party of 3 splitboarders “kicked off a good slide in a NE facing chute” as the first person descended (observation). On the approach, both Dave and the boarders separately had small whumpfs and cracking. In his pit, Dave found weak and sugary snow under a slab of new and winbblown snow. His stability test fractured ridiculously easy (ECTP1). His video and observation mirror the snowpack the splitboarders triggered. Luckily, they were going one at a time, no one was caught, and the party had rescue gear. Although they were extremely disappointed in their decision making, they modeled good travel protocol which paid safety dividends.
The snowpack in Cooke City is not much better. New snow and wind-loading have created instability. Skiers noted a natural avalanche on east Henderson (photo) and 2 parties had cracking and whumpfing as they toured (Erma Mine ob) (Henderson ob).
The snowpack structure is weak and unstable. Whumpfs and shooting cracks under our feet are a sure sign that we can trigger a slide. Given the late start to the ski season we are hungry to get out there, but need to reign in our enthusiasm. The boarder’s self assessment of their near-miss is valuable. He writes, “My thought was that it was slightly questionable but manageable if mitigated and ridden carefully, which was stupid reasoning, we all kinda agreed on that and dove into a sketchy situation, which ended up being a close call.”
In the last 4 days the mountains around Bozeman received around 5” of snow with the Big Sky area and southern Madison and southern Gallatin Ranges getting 12-15”. This snow was blown into wind slabs that overlay weaker, faceted snow found at higher elevations (around 9,000’). Alex’s video from the Yellowstone Club gives us a first hand look at this weak and unstable structure.
On Saturday, I found a thin wind crust easily cracking up Hyalite (observation) and skiers at Bridger Bowl saw the same (observation). The snowpack is thin and avalanche risk will likely be confined to wind-loaded gullies or bowls. Ice climbers need to be careful of triggering small pockets of drifted snow. Skiers should heed the sage advice, “It’s there’s enough snow to ski, there’s enough snow to avalanche”.
The snowpack in Island Park (IP), West Yellowstone and Cooke City is similar. New snow and wind-loading have created dangerous avalanche conditions. Evidence includes a lot of slides in Black Canyon outside IP, a snowboarder triggered avalanche in Lionhead, a natural slide outside Cooke City and skiers getting whumping and cracking as they toured. Avalanches, cracks and collapses warn us to not enter avalanche terrain. Carry avalanche rescue gear (beacon, shovel, probe) and make sure your gear and skills are in working order.
If you venture out, please fill an observation form. It does not need to be technical. Did you see any avalanches? How much snow is on the ground? Was the wind moving snow? Simple observations are incredibly valuable. You can also contact us via email (mtavalanche@gmail.com), phone (406-587-6984), or Instagram (#gnfacobs).
Upcoming Avalanche Education and Events
Our education calendar is full of awareness lectures and field courses. Check it out: Events and Education Calendar.
TONIGHT! 6:30 p.m., FREE Avalanche Awareness at MAP Brewing
Tuesday, December 5th, 6:00 p.m., Free Avalanche Awareness + Beacon Demo Clyde Park Community Hall, hosted by the Big Sky SnowRiders
Tuesday, December 9th, 9:00 a.m. to 3:00 p.m., West Yellowstone Motorized Avalanche Fundamentals, Pre-registration and more information HERE.
We offer Avalanche Fundamentals with Field Session courses targeted towards non-motorized users in December and January and one geared towards motorized users in January. Sign up early before they fill up.
Loss in the Outdoors, is a support group for those who have been affected by grief and loss related to outdoor pursuits. Check out the link for more information.
We travel with a lot of electronics that could interfere with our avalanche transceiver, both as a victim and as a rescuer. Check out our article on Electronic Warfare to learn what to do.