Good morning. This is Alex Marienthal with the Gallatin National Forest Avalanche Forecast on Sunday, January 22nd at 7:00 a.m. Today’s forecast is sponsored by Mystery Ranch and Avalanche Alliance. This forecast does not apply to operating ski areas.
This morning there is zero to a trace of new snow in the mountains. Temperatures are single digits to teens F. Wind is out of the northwest to southwest at 10-20 mph with gusts of 25-35 mph. Today, temperatures will reach high teens to low 20s F, and wind will be west-north at 5-20 mph. The previously forecasted storm has faded dramatically, and today will have light snowfall with a trace to 2” possible by tomorrow morning.
In the mountains around Big Sky, West Yellowstone and Cooke City a weak layer of surface hoar buried 1-2 feet deep makes it possible for a person to trigger avalanches. Yesterday, moderate wind blew recent snow into fresh slabs that can avalanche under the weight of a person and could cause an avalanche to break deeper on buried surface hoar. Over the last week natural and human triggered avalanches broke on the surface hoar (Two top details and photo, Lionhead details and photos, Buck Ridge photo, Cooke City photo). This layer can be tricky to assess because it is not on every slope, and it isn’t breaking in every stability test (Cooke City video, Lionhead video). It will become less likely to find an unstable slope as time passes without additional snowfall, but surface hoar can remain unstable for a long time and is notorious for surprises. Before riding in steep terrain, look for and avoid fresh drifts, and dig to look for and assess buried weak layers. Or, keep things simple and avoid steep slopes entirely (Hebgen Lake video). Avalanches breaking on weak layers near the ground are unlikely, but a person might be able to trigger a slide from a shallower area in the snowpack where these layers are easier to affect. Today avalanches are possible to trigger and danger is MODERATE.
Over the last week, the Bridger Range and Hyalite received 5-7” of snow which was drifted into shallow wind slabs by moderate to strong west-northwest wind. Triggering these wind slabs has become less likely without additional new snow the last couple days, but a few wind-loaded slopes could remain unstable. Yesterday Ian and I looked at the snowpack on Saddle Peak and found weak snow buried 6-8” deep below a hard wind slab (video). This indicates some drifts might remain unstable for longer than usual. Steer clear of round deposits of snow, especially where being caught in an avalanche would have high consequences like in steep terrain, above cliffs, rocks or trees.
We have not seen avalanches breaking on weak layers near the ground in the mountains around Bozeman, but plenty of weak snow exists. Before fully committing to ski or ride steep slopes, dig down to look for and assess potential weak layers. Today the avalanche danger is MODERATE on wind-loaded slopes. Otherwise the snowpack is generally stable and danger is LOW on non-wind loaded slopes.
Please share avalanche, snowpack or weather observations via our website, 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.
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).