Good morning. This is Mark Staples with the Gallatin National Forest Avalanche Advisory issued on Friday, March 4, at 7:30 a.m. Alpine Orthopedics, in cooperation with the Friends of the Avalanche Center, sponsors today’s advisory. This advisory does not apply to operating ski areas.
Since yesterday morning the mountains near Cooke City received 6 inches of snow while all other areas received 1-3 inches. Yesterday evening westerly winds increased to 20-30 mph but decreased this morning to 10-20 mph. Temperatures this morning were in the low teens F and should warm to the mid 20s F. Today will be mostly cloudy and only a trace of snow might fall by tomorrow morning. Snowfall should resume on Saturday.
The Bridger, Madison and Gallatin Ranges, the Lionhead area near West Yellowstone:
The current weather pattern is perfect - a few inches of snow everyday with light winds and mostly cloudy skies. This type of weather:
- Prevents the formation of new persistent weak layers.
- Limits wind slab formation.
- Keeps the skiing and riding good without stressing the snowpack.
Avalanche issues in the new snow are minimal. New snow has mostly bonded well to the old snow surface. Some new snow fell as little pellets called graupel which can be a temporary weak layer but usually bonds within 24-48 hrs. Also, a few fresh wind slabs may exist after a few hours of increased westerly winds last night.
Avalanche issues in the old snow primarily involve hard wind slabs that formed last weekend and early this week. Fortunately these hard slabs have mostly bonded and triggering one will be difficult though not impossible. Likely areas to trigger one of these hard slabs are slopes that have been scoured by winds and have a thin and weak snowpack. The Big Sky Ski Patrol triggered a small pocket of old snow with explosives in one of these areas Most of these slopes remain scoured, but a few may have slabs from cross loading winds.
For today, with mostly light winds and no widespread stability concerns, the avalanche danger is rated LOW. Generally safe avalanche conditions exist, but watch for unstable snow on isolated terrain features because a low danger ≠ no danger.
The mountains around Cooke City and the Washburn Range:
The mountains near Cooke City received 6 inches of new snow. Much of this snow fell as little pellets called graupel that can be a temporary weak layer. Deeper layers of snow are well bonded and human triggered avalanches should be small. One isolated exception – a skier triggered avalanche near Round Lake on Sunday. This avalanche occurred on facets near an ice crust about 2 ft deep. Fortunately this layering does not exist on most slopes. For today the avalanche danger is rated MODERATE on wind loaded slopes. All other slopes have a LOW avalanche danger.
Eric 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.
PHOTOS, SNOWPITS, VIDEO and SURVEY RESULTS
- We’ve recently uploaded more photos and snowpits to our web site.
- We’re creating a series of “How To…” stability test videos. So far we’ve made clips on performing a CT and ECT. There are located under <Stability Tests> on the Resources page.
- The results from our survey are posted online. Thanks to all who participated. You can check out the results at http://bit.ly/fpLuSi.
UPCOMING EVENTS
TOMORROW: Pinhead Classic
The 30th Annual Pinhead Classic is on this Saturday, March 5th. “Gangsters and Flappers” is this year’s costume theme, so come dressed up to race, socialize and win great prizes. Registration is $30 and gets you course entry, t-shirt, pint glass, beverages, dinner, and dancing. All proceeds benefit the Friends of the Avalanche Center. Check out the website http://pinheadclassic.com for details.