Good Morning. This is Alex Marienthal with the Gallatin National Forest Avalanche Forecast on Sunday, March 28th at 7:30 a.m. Today’s forecast is sponsored by Summit Motorsports and Ski-Doo and Montana State Parks. This forecast does not apply to operating ski areas.
Yesterday morning 1-2” of snow fell near Bozeman and Big Sky with no snow elsewhere in the last 24 hours. This morning temperatures are high 20s to low 30s F and wind is west-southwest at 15-25 mph with gusts of 35-55 mph. Today, strong westerly wind will continue with speeds increasing through the day, and temperatures will reach mid-40s to 50 F. A strong cold front will arrive early tomorrow with 1-3” of new snow possible by morning and more snow through tomorrow.
Think twice about riding or skiing steep slopes today. Avalanche danger will increase as steady strong winds continue to drift recent snow into thick slabs. Yesterday near Mt. Blackmore a skier remotely triggered an 8-10 foot deep avalanche that broke on weak, sugary snow near the ground (photos and details), and we heard of a recent natural deep slab in Flanders Creek (photo). These are the first avalanches to break on this deep weak layer since February. The likelihood of triggering a deep slab avalanche remains low, but these slides are a sign that the load of recent snow has made it is possible.
The most likely type of avalanche you can trigger today is a fresh drift of snow 1-2 feet deep. Yesterday skiers triggered fresh wind slabs in Hyalite (photo and details, photo and details), the Bridgers, and the Madison Range (photo). Similar slabs will grow larger and easier to trigger through today, and could break deeper on weak snow near the ground, or break wide on a weak layer buried below recent snow. We have found the weak layer below the recent snow to be unstable in some of our snowpits, but not all, near Cooke City (Cooke video) and Buck Ridge (video, video).
Warm temperatures and wind-loading will increase the chances of cornice falls, which could trigger larger avalanches. Lastly, above freezing temperatures and sunny skies today make wet snow avalanches possible. Expect this hazard on lower elevation slopes and slopes that receive direct sun. Where the snow surface gets moist, loose snow avalanches will become easy to trigger.
There is a long list of avalanche hazards today, and stability will decrease with strong wind and above freezing temperatures. To stay safe, make a plan to avoid wind-loaded slopes and complex terrain, and have options to avoid steep slopes altogether. If you plan to ride on slopes steeper than 30 degrees, carefully evaluate the stability of recent snow and consequences of being caught in a slide. Today, on wind-loaded slopes human triggered avalanche are likely and large natural avalanches are possible. The avalanche danger is CONSIDERABLE on wind-loaded slopes and MODERATE on all other slopes.
Upcoming Avalanche Education and Events
See our education calendar for an up-to-date list of all local classes. Here are a few select upcoming events and opportunities to check out:
March 29, 6 p.m., Free 1-Hour Avalanche Awareness, online Link to Join HERE
April 5, 6:30 p.m., Forecaster Chat with Alex Marienthal, hosted by Uphill Pursuits, “Spring Snowpack and Forecasting Tools”. Link to Join.
On Monday, March 22, a skier in Colorado was caught and killed by an avalanche in the backcountry near Beaver Creek Ski Area (preliminary information and photos). Last Saturday in California, a snowmobiler died when he stepped off his sled, broke a large cornice, and triggered an avalanche below (details and photos). We are sad to hear of these losses. The US now totals 35 avalanche fatalities.