GALLATIN NATIONAL FOREST AVALANCHE ADVISORY
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Check out our Season Summary for a brief recount of our accomplishments this year: http://www.mtavalanche.com/current/SeasonSummary06-07.pdf
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SPRINGTIME AVALANCHE INFORMATION
The Avalanche Center is officially closed and won’t be issuing advisories until next fall. However, this doesn’t mean the avalanche danger is gone. Spring can be notorious for big storms, and if we’re lucky we’ll get a few wet dumps to ward off the fire season. As you head out to play you’ll want to keep a few things in mind.
DRY SNOW AVALANCHE DANGER
This season we had weak snow near the ground that will be a concern until it all melts away. Faceted snow sitting on an icy mass is still showing signs of instability. The entire winter’s snow is sitting on top of these facets, so avalanches will be deep and potentially big. This layer was triggered on a high elevation north-facing slope on April 2nd. The good news is that slopes that are dry to the ground are the exception rather than the rule.
Slopes that got wet and refroze will have an ice crust a few inches think buried a few feet under the new snow. On these slopes the biggest avalanche concern will be bonding of this new snow to the crust as well as weak layers that formed in between storm events. In these cases you won’t have to dig far to assess the stability.
WET SNOW AVALANCHE DANGER
Sunny, warm days coupled with nights that stay above freezing can create dangerous avalanche conditions. South facing slopes mid-day can also become unstable as the sun melts the surface snow, which increases the instability. If you are out and find yourself sinking past your boot tops in glop, or see growing pinwheels of snow, you should probably retreat back to the car since these are signs the snow is getting wet enough to slide.
If you want to know more about wet avalanches you can read a short article that I wrote in Outside Bozeman this spring: http://www.mtavalanche.com/current/WetAvalanche.pdf
COMMON SENSE
Springtime days are longer, warmer and more comfortable—a great combination. But now is not the time to let your guard down. All backcountry safety rules still apply! Travel one at a time on all avalanche terrain, and carry a beacon, shovel and probe.
Have a great spring and summer!
Doug Chabot
Report from:
Gallatin National Forest Avalanche Center
Gallatin