Good Morning. This is Ian Hoyer with the Gallatin National Forest Avalanche Forecast on Friday, March 26th at 7:15 a.m. Today’s forecast is sponsored by Summit Motorsports and Ski-Doo and Bridger Bowl. This forecast does not apply to operating ski areas.
Since yesterday morning, 1-3” of snow fell across most of the advisory area, with 5” in Hyalite and 7-9” of low density snow at the Yellowstone Club. Winds are 5-10 mph out of the north and east, with gusts of 25 mph in the Bridger Range where the winds shifted to the west early this morning. Winds will shift westerly across the rest of the advisory area and remain light this morning, before increasing a bit later this afternoon. Temperatures are in the teens and 20s and will rise into the 20s and low 30s. Snow flurries today and tonight won’t amount to much accumulation.
There are a number of avalanches concerns today, stemming from the new snow, old snow, winds, and strong spring sun.
With generally light winds, the new snow does not have much cohesion and won’t cause widespread issues by itself. Stay on alert for isolated places where the new snow was drifted into more cohesive slabs. The additional weight of new snow will slow down the stabilization of older drifts. With shifting winds recently (including strong, unusual east winds in the Bridger Range last right), these drifts could be found on any aspect. If winds pick up this afternoon, watch for reactive, freshly forming drifts.
Underneath the recent snow, on some slopes there is a thin layer of weak snow (called near-surface facets). Dave and I spent the last two days digging snowpits looking for this layer in Cooke City and only found it on west facing slopes (video). We haven’t found a similar pattern in the rest of our advisory area. Even in Cooke City, I’m not confident that it is confined exclusively to a particular aspect. Expect to find this layer on west facing slopes near Cooke City, but it’s worth digging to look for it on any slope. If you find it, move to another slope where it doesn’t exist. There are many slopes with good riding conditions where the recent snow is well bonded.
Pay attention if the sun comes out, because if it does, you will quickly be able to trigger loose snow avalanches in the new snow. Roller balls and pinwheels are clear signs that the conditions for loose avalanches are developing.
While we haven’t seen an avalanche on the weak layers at the ground in weeks, the load of recent snow is starting to pile up. 2.5” of snow water equivalent has accumulated in many areas over the last week. I don’t expect avalanches to break near the ground today, but the nagging concern is starting to creep back in.
With the possibility of triggering a range of different types of avalanches today, the avalanche danger is MODERATE.
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”.
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.