Good morning. This is Ian Hoyer with the Gallatin National Forest Avalanche Forecast on Friday, January 20th at 7:00 a.m. Today’s forecast is dedicated to Tyler Stetson. Tyler was killed in an avalanche in Beehive Basin on this day fifteen years ago. This forecast does not apply to operating ski areas.
There is a trace to an inch of new snow across most of the advisory area, with 2” in Taylor Fork. Winds are 5-10 mph gusting 15-25 mph, out of the W-NW near Bozeman and N-E elsewhere. Temperatures are in the single digits and teens F this morning. Under mostly sunny skies, temperatures will rise into the teens and 20s F. Winds will generally remain light, with perhaps some gusts past 20 mph, shifting to the north and west. No new snow is expected today
Snow that fell over the last week has drifted into slabs that you can trigger today. Watch out for slopes with slabs of drifted snow more than a few inches deep that haven’t yet bonded (or places where there is any slab at all on slopes where just getting knocked off your feet would have big consequences). Wednesday’s snowboarder triggered slide on Saddle Peak illustrates this concern (video), as does a long running slide in Argentina Bowl (photo). This issue isn’t present everywhere, there are many places where these slabs are very thin or they have had time to bond and stabilize. Cracks shooting out in front of your skis or sled indicate you’ve found a drift that remains unstable and should immediately retreat off steep slopes.
In the mountains around Big Sky, West Yellowstone and Cooke City there is a weak layer of surface hoar buried 1-2 ft deep. There have been both natural and human triggered avalanches on this layer this past week (Two top details and photo, Lionhead details and photos, Buck Ridge photo, Cooke City photo). As Alex found yesterday near Cooke City, this layer is not on every slope and even on slopes where it’s present, it isn’t breaking in every stability test (Cooke City video). This makes it hard to assess (Lionhead video). Your options are to dig, carefully test this layer and accept a certain degree of uncertainty, or keep things simple by avoiding steep slopes entirely (Hebgen Lake video). We haven’t had reports of this layer buried in the mountains around Bozeman.
Weak layers near the ground still deserve mention and a degree of consideration. It’s been a couple weeks since the last avalanche broke on these layers, but it’s not out of the realm of possibility you could trigger a slide from a thin spot that propagates deeply and results in a large slide. On Wednesday, skiers on Ross Peak made the wise call to back off a steep slope after getting unstable test results breaking near ground (observation). Remain wary of these layers.
With weak layers throughout the snowpack and recent wind drifts, triggering avalanches remains possible. For today the avalanche danger is rated MODERATE on all slopes.
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Snow that fell over the last week has drifted into slabs that you can trigger today. Watch out for slopes with slabs of drifted snow more than a few inches deep that haven’t yet bonded. In the mountains around Big Sky, West Yellowstone and Cooke City there is a weak layer of surface hoar buried 1-2 ft deep that has been avalanching. Dig, carefully test this layer and accept a certain degree of uncertainty, or keep things simple by avoiding steep slopes entirely.
Upcoming Avalanche Education and Events
Our education calendar is full of awareness lectures and field courses. Check it out: Events and Education Calendar.
Every Saturday, 10 a.m. - 2:00 p.m. Avalanche Rescue Training, drop in for any amount of time. Round Lake Warming Hut, Cooke City. Free.
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.
KING AND QUEEN OF THE RIDGE, FEBRUARY 4TH
Do you like to hike? Do you like to ski? Then the King & Queen of the Ridge is for you. Hike, ski and raise money for the Friends of the Avalanche Center in their 2nd biggest fundraiser of the year. Join the effort to promote and support avalanche safety and awareness! Fundraising prizes for the top 5 individuals who raise over $500. No racing is necessary to compete for the fundraising prizes. Info is HERE. Race participants for the February 4th event must register separately with Bridger Bowl HERE.
Full accident reports have been released for most of this season’s avalanche fatalities. Take a few minutes to read back through them and see what lessons you can learn from these tragic accidents (accident report archive).