Good morning. This is Doug Chabot with the Gallatin National Forest Avalanche Advisory issued on Tuesday, March 5 at 7:30 a.m. Montana Ale Works in partnership with the Friends of the Avalanche Center sponsors today’s advisory. This advisory does not apply to operating ski areas.
This morning under clear skies, mountain temperatures are in the single digits with west to southwest winds averaging 10-15 mph. There’s no new snow to report. Today will be mostly sunny with temperatures warming into the upper teens and light southwest winds. This evening a Pacific low pressure system will bring cloudy skies and a chance of snow tomorrow.
Bridger Range Madison Range Gallatin Range
Lionhead area near West Yellowstone Cooke City
Yesterday, our main avalanche concern was on wind–loaded slopes. Northwest winds and 5-7 inches of snow created shallow drifts at the ridgelines. These drifts are still there and remain one of our avalanche concerns. They will not be very sensitive or large, but as Mark witnessed in Cooke City they have the potential to flush a person down unforgiving terrain (photo).
Throughout our advisory area faceted and weak layers of snow can be found in the upper three feet of the snowpack. These layers of concern vary from surface hoar to small, angular crystals. Stability tests quickly reveal them. On Sunday, in Dudley Creek in the northern Madison Range, Eric found a variety of faceted layers that were breaking in snowpits and causing him concern (video).
On some slopes the snowpack is shallow, weak and unsupportable. An unscientific, but valid test to find these slopes is to step onto the snow: sinking to the ground pinpoints a weak snow structure. These zones can be found on lower elevation slopes as well as rocky, wind-swept terrain above treeline (Hardscrabble avalanche pic). Last week, I found poor structure on Mount Ellis and Mark and Eric looked at a natural avalanche in thick trees on Mt Wheeler with a similar problem (photo). On Sunday, two snowboarders were caught in a small avalanche in the forest below the highest History Rock meadow in Hyalite (photo). I was unable to find the slide yesterday, but besides surfing over logs and head-faking tree branches I can attest to the thin and weak structure of the snowpack…in the trees.
Many slopes are stable, but some are not. The safest way to find the difference is to stop, dig and test the slope you plan on riding. So far we have been spared avalanche fatalities this season, but other regions have not. Last weekend a skier was killed in the Tetons as he climbed up a steep couloir (article) and a snowmobiler was killed in Utah on a slope with a snowpack very similar to ours (accident report). I mention this as a warning to not let our guard down. For today, the avalanche danger is rated MODERATE since it is still possible to trigger slides.
I will issue the next advisory tomorrow morning at 7:30 a.m. If you have any snowpack or avalanche observations drop us a line at mtavalanche@gmail.com or call us at 587-6984.
Montana Ale Works Fundraiser Dinner
Tickets are on sale now to the 5th Annual Friends of the Avalanche Center Dinner and Wine Pairing on Wednesday, March 13th at 6:00 p.m. Call the host stand at 587-7700 to reserve your space. Tickets are $75 and all proceeds go to the Friends of the Avalanche Center. There are only 40 tickets available and this event sells out every year so get them while you can!