Good morning. This is Alex Marienthal with the Gallatin National Forest Avalanche Forecast on Monday, April 8th, at 7:00 a.m. Today’s forecast is sponsored by Cooke City Super 8/Bearclaw Bob’s and Avalanche Alliance. This forecast does not apply to operating ski areas.
Since yesterday morning the Bridger Range, Hyalite and Big Sky received 3-7” of new snow, and 1-3” fell elsewhere. Wind has been out of the northwest at 10-20 mph with gusts of 25-40 mph. Temperatures are teens to 20s F. Today, temperatures will reach mid-30s F under clearing skies, and wind will be west-northwest at 10-15 mph with gusts to 25 mph. The next chance for a few inches of snow is during the day tomorrow.
Near Bozeman and Big Sky the snow that fell over the weekend creates heightened avalanche conditions and you can trigger avalanches that break within or below this snow. This afternoon the danger will increase due to sunshine and temperatures above freezing making large wet loose avalanches likely.
Over the weekend the Bridger Range got over 2 feet of snow equal to 2.5-3.0” of snow water equivalent (SWE), and Big Sky and Hyalite got 7-12” equal to 0.7-1.2” SWE. Yesterday in the Bridgers, Dave and I measured the snow and investigated stability at The Ramp (video) and The Throne (video), and there were many skier triggered slides that broke within the new snow throughout the range (Wolverine photos, Frazier photos, Fairy Lake photos, N. Bridgers photos, Ross Peak photos). Similar avalanches can be triggered today. Although these types of instabilities typically heal quickly, today you should steer clear of fresh drifts and carefully assess the potential for the new snow to slide. Choose smaller slopes and slopes without cliffs, trees, rocks or gullies that would increase the chances of being injured or killed in any size slide.
When the sun comes out stability will quickly decrease and make wet avalanches that can run long distances. These slides could become large where more snow fell, and even a small wet slide will easily knock you over or carry you down a steep slope. Plan to be off of and out from below steep slopes before the recent snow becomes moist or wet. A sticky snow surface is a sign to find shadier or lower angle slopes.
Avalanches breaking on deeper weak layers are unlikely, but not out of the question on higher, shady slopes that didn’t get as wet last week. Dig down a few feet to check for buried weak layers before getting onto steep slopes.
Today the avalanche danger starts at MODERATE and will increase to CONSIDERABLE for wet snow avalanches later in the day.
Near West Yellowstone, Island Park and Cooke City less snow over the weekend and more clouds today will minimize the threat of wet snow avalanches compared to other areas. Over the weekend these mountains got 4-7” of snow equal to 0.4-0.7” SWE. You can trigger avalanches where new snow is drifted into thicker slabs, and wet loose avalanches will be possible if the sun comes out (video). Wind slabs or wet loose avalanches could easily slide on the hard melt-freeze crust below.
Watch for cracking across the snow surface as a sign unstable drifts exist, and if the snow surface gets moist expect wet loose avalanches. Choose slopes without trees, cliffs or other terrain traps that would increase the chances of being injured in even a small slide. Deeper avalanches are unlikely, but not impossible. If you are riding steep, consequential slopes it is a good idea to dig down a few feet to look for weak layers and assess snow stability. Avalanche danger is MODERATE near Cooke City, West Yellowstone, Island Park, and in the southern Madison and southern Gallatin ranges.
If you get out please submit an observation. 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 by email (mtavalanche@gmail.com), phone (406-587-6984), or Instagram (#gnfacobs).
Upcoming Avalanche Education and Events
Hyalite Road Closure: Hyalite road is closed to ALL MOTORIZED VEHICLES until the morning of May 16. This is a regular annual road closure to reduce road damage during the spring thaw. Bicycle and foot traffic are allowed. Contact the Bozeman FS Ranger District for more info.
Events and Education Calendar.
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.
The total number of avalanche deaths in the US stands at 13. On March 29, a snowboarder was killed on Mt. St. Helens when a cornice he was standing on broke and triggered the slope below.