Good morning. This is Ian Hoyer with the Gallatin National Forest Avalanche Forecast on Saturday, March 16th at 7:00 a.m. Today’s forecast is sponsored by Uphill Pursuits and Cooke City Super 8/Bearclaw Bob’s. This forecast does not apply to operating ski areas.
Skies are clear and there is no new snow. Temperatures are in the 20s and low 30s F this morning. Winds are 5-15 mph with 20-30 mph gusts out of the north and east. Moderate winds will continue from the north and east today. Temperatures will rise into the 30s and 40 F. Sunny skies and increasingly warm temperatures are in store for the next few days.
Changes in the snowpack make us nervous and the warmup that’s happening right now is a significant change. It’s going to be around 5 degrees warmer today than yesterday, when mountain temperatures already climbed above freezing. With this, we expect to see more melting of the surface snow. When formerly dry snow gets wet for the first time it can make it easier to trigger avalanches breaking on deeper weak layers. The uncertainty is high on this, but this season’s snowpack has surprised us time and time again with what small changes it takes to trigger big slides. Don’t let it surprise you today, make a conservative plan and stick to it. Take a minute to look at the pictures and videos of the large slides over the last week and reflect on the catastrophic nature of these avalanches (Absaroka details, Blackmore video, Beehive video, Beehive photos, Cooke City activity list).
Smaller slides may also break in wind drifts that formed from the snow that fell mid-week that has now been drifted by unusual east winds. Loose wet avalanches are also expected on sunny slopes today, but shouldn’t be at the forefront of your mind, because you should already be planning on avoiding steep slopes so you don’t trigger a huge, 3 to 12 ft thick, deep slab avalanche breaking near the ground!
Human triggered avalanches are likely and the avalanche danger is CONSIDERABLE.
In the Bridger Range, and Lionhead and Island Park areas, the general snowpack structure is similar and the set of concerns are the same, but triggering a big slide is a bit less likely. In the southern areas the weak layers are getting buried deep enough that it’s getting harder to trigger slides and in the Bridgers there has been less loading.
Thinking about getting into steep terrain isn’t unreasonable in these areas, but set yourself up for success by considering both the possibility of triggering a large, deep slide and the more likely case of triggering a smaller wind slab or wet loose avalanche as the day heats up. Paying close attention to the surface snow will give you a good idea about the likelihood of these shallower instabilities. Watch for terrain with rocks, cliffs, gullies, or trees beneath you that would magnify the consequences of one of these smaller slides. Good travel practices (traveling one at a time, wearing rescue gear, and watching your partner from a safe spot) are the best answer to the possibility of getting surprised by a big slide.
Human-triggered avalanches are possible and the avalanche danger is rated MODERATE.
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.
TODAY in Cooke City: Free Rescue Practice from 10 a.m.-2 p.m. at Round Lake Warming Hut. This is the last weekend this program will be running this season.
Loss in the Outdoors is a support group for those affected by loss and grief related to outdoor pursuits. Check out the link for more information.
On Tuesday, a backcountry skier was caught and killed by an avalanche near Lost Trail Pass. Preliminary information is available here.