This is Mark Staples with the avalanche forecast for Thursday, January 9th, at 7:00 a.m. sponsored by the Avalanche Alliance and the Idaho State Snowmobile Association - Avalanche Fund. This forecast does not apply to operating ski areas.
Snow fell yesterday and again last night favoring mountains near Bozeman & Big Sky
- 7-12” snow (0.7” SWE) in Hyalite Canyon, northern Gallatin Range
- 7” snow (0.4” SWE) in Big Sky, northern Madison Range
- 5” snow (0.3” SWE) in the Bridger Range and near Cooke City
- 4” snow (0.3” SWE) in the southern Madison Range
- 2” snow (0.1” SWE) in the Lionhead and Island Park areas
This morning winds have eased since yesterday in most areas, averaging 5-10 mph from the N. In the Bridger Range winds are coming from the W, and there are a few higher gusts at the ridge. Near Cooke City winds remain a bit elevated blowing 24 mph gusting to 44 mph from the N. Temperatures are in the low teens F up high and upper teens at lower elevations.
Today will be stunning with a fresh coat of white paint, light winds from the NW, and cold air keeping high temperatures mostly in the upper teens to 20 degrees F. Low level clouds and fog will linger through the morning followed by mostly sunny skies. Friday will have a brief warm up followed by a decent shot of snow Friday night through Saturday.
Wind slab avalanches are a concern near ridgetops from wind loading yesterday (loading this morning in Cooke), but they will be difficult to identify because they are covered by fresh snow. Use your judgment to determine where winds have deposited snow (cornices are a good clue) and avoid those places.
Persistent slab avalanches 2-4 deep may still happen. The likelihood is dropping and the weak layer of facets is getting stronger on many slopes BUT NOT ALL. Lionhead has lots of weak snow. A ski guide near Cooke City yesterday found pretty strong snow in two snowpits, but then got a collapse in an area with thinner snow (~2.5’ deep). In the southern Madison Range, I experienced widespread collapsing 6 days ago in Cabin Creek, then Ian was nearby in the Taylor Fork 2 days ago and didn’t experience any collapsing. He did see a few recent avalanches and got some poor results in snowpack tests, so he was worried about being lulled into a false sense of confidence.
The challenge is that we can get clear warning signs of instability, but the snowpack never gives us clear signs of stability and there is always a lot of uncertainty. The snowpack may be moving in the right direction, but keep a healthy dose of skepticism. Read more in this blog post I wrote last week.
Today safe travel requires conservative decision making and cautious route finding, and today the avalanche danger is CONSIDERABLE. Avoid areas loaded by yesterday’s winds. If you choose to enter the peripheries of avalanche terrain, take baby steps and consider the consequences of a slide if your assessment is wrong.
Yesterday natural avalanches were spotted rumbling down steep terrain just north of Bridger Bowl during a short period of rapid snowfall and wind loading. Early yesterday morning, the Bridger Bowl Ski Patrol triggered wind slabs just under the ridge 4-12 inches deep, then had to shut down the ridge midday due to snowfall and wind.
The good news is that winds weren’t hurricane force, and shifting directions prevented them from doing too much damage. The challenge today is that wind slabs will be hard to identify with fresh powder on top of them. Use your judgment to determine where winds deposited snow yesterday (cornices are a good clue) and avoid those places.
You’ll likely trigger a wind slab in areas loaded by yesterday’s winds. There’s also a chance that a slide in one of these places could break deeper on old facets. Today the avalanche danger is CONSIDERABLE on wind loaded slopes, and MODERATE on slopes not loaded by yesterday’s winds.
Very similar snowpack conditions exist in the Centennial Range near Island Park. Watch for wind slabs near ridge tops from winds that transported some snow yesterday. Persistent slab avalanches are still a major concern. The likelihood of triggering one has dropped but it’s not the same on all slopes. More likely places to trigger persistent slab avalanches are slopes with a thinner snowpack where you’re also more likely to hit a rock and smoke an A-arm on your sled.
Dave and Shannon (our education coordinator) rode with a few top notch guides and educators near the top of Yale Creek yesterday. They found signs of improving stability but also found signs of instability. He describes the situation well in this video, watch it. Read more in this blog post I wrote last week.
For today with lingering weakness in the snowpack, the avalanche danger is MODERATE. Heads up - this danger rating spans a wide range of conditions, don’t let your guard down.
Upcoming Avalanche Education and Events
Our education calendar is full of awareness lectures and field courses. Check it out: Events and Education Calendar
Avalanche Fundamentals with Field Session for non-motorized travelers THIS WEEKEND. Sign up ASAP or sign up for one on the last weekend of January.
Every weekend in Cooke City: Friday at The Antlers at 7 p.m., Free Avalanche Awareness and Current Conditions talk, and Saturday from 10 a.m.-2 p.m. at Round Lake Warming Hut, Free Rescue Practice.
On Tuesday, a skier was killed in an avalanche in Colorado (initial report from CAIC). On Sunday a skier was killed, and a second sustained injuries in an avalanche in western Wyoming (preliminary information from BTAC). Our hearts go out to the skiers’ friends and family, backcountry partners, and the rescue teams.
Thank you for sharing observations. Please let us know about avalanches, weather or signs of instability via the form on our website, or you can email us at mtavalanche@gmail.com, or call the office phone at 406-587-6984.