Good morning. This is Alex Marienthal with the Gallatin National Forest Avalanche Forecast on Sunday, March 27th at 7:05 a.m. This information is sponsored by Bridger Bowl and Cooke City Motorsports. This forecast does not apply to operating ski areas.
Yesterday, temperatures reached high 30s to low 50s F, and wind was from the southwest-west at 10-20 mph with gusts of 30-40 mph. Overnight, temperatures remained above freezing at elevations below 10,000 feet. This morning temperatures are 30-40 F and wind is 5-15 mph out of the west-southwest. Today the wind will remain light, skies will be mostly clear, and temperatures will reach 40s to mid-50s F, nearing 60 F in the mountains near Bozeman and Big Sky.
Dangerous avalanche conditions exist today. Last night was the fourth night in a row that the snowpack did not refreeze well, or only refroze slightly, after high temperatures were in the 40s and 50s F during the day. Today temperatures will be warmer. Any supportable crusts that formed on the surface overnight will melt quickly, and the wet snowpack will become unstable.
This will be the fifth day in a row of above freezing temperatures and the warmest yet. Sunshine and light wind will allow the snowpack to heat up quickly. To make matters worse, buried weak layers are being saturated with melt-water for the first time this season which means water may pool along these layers and make large to very large human triggered wet slab avalanches likely, and large natural avalanches possible. These could be a foot deep, or the entire snowpack, and either size is potentially deadly.
Yesterday, the Bridger Bowl ski patrol closed all avalanche terrain early and saw multiple natural wet slides (photo and details), Big Sky ski patrol triggered a 3-4’ deep wet avalanche, a skier on Mt. Blackmore saw a wet loose avalanche (photo), and skiers near Electric Peak experienced whumphing and saw a natural wet slide (photo and details). Today I expect larger avalanches and more widespread wet snow instability. Wet snow avalanche activity will start to occur on slopes that were shady and had dry snow yesterday or the day before, and on these slopes avalanches breaking on persistent weak layers could be dry or wet (snowmobile triggered slide in Taylor Fork yesterday, skier triggered and caught on Woody Ridge).
Plan to avoid travel on and underneath steep slopes today. Consider what terrain is above you and minimize time spent in runout zones where natural wet avalanches could deposit deep, heavy debris piles. Today, human triggered avalanches are likely, and large natural avalanches are possible. Avalanche danger is CONSIDERABLE.
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This article in the Billings Gazette highlighting Dave’s January accident, shoulder injury and rescue is worth your time. Plan ahead and prepare for dealing with an injury in the backcountry and think about how you’d call for outside help.