GNFAC Avalanche Forecast for Sat Mar 30, 2013

Not the Current Forecast

Good morning. This is Eric Knoff with the Gallatin National Forest Avalanche Advisory issued on Saturday, March 30 at 7:30 a.m. Cooke City Motor Sports & Yamaha in partnership with the Friends of the Avalanche Center sponsors today’s advisory. This advisory does not apply to operating ski areas.

Mountain Weather

Over the past 24 hours the mountains picked up 1-3 inches of high density snow above 8,000 ft. This morning temperatures are in the twenties F and winds are blowing 10-20 out of the WNW. A northwest flow aloft will keep skies cloudy this morning producing a slight chance of mountain snow and valley rain. Conditions will dry out this afternoon as a weak ridge of high pressure builds over the area. Today, temperatures will warm into the mid-30s to low 40s F and winds will remain light out of the WNW.    

Snowpack and Avalanche Discussion

Bridger Range   Madison Range   Gallatin Range   

Lionhead area near West Yellowstone   Cooke City

Above 8,000 ft. 1-3 inches of snow fell in most locations, below 8000 ft. precipitation fell in the form of rain. Depending on what the weather does today, there will be a few avalanche problems to consider.

On lower elevation slopes, wet loose avalanches will be the main problem. Multiple days of above freezing temperatures with only light refreezes at night, has reduced the snowpack to isothermal mush. These types of conditions are most dangerous where there are steep slopes and associated terrain traps such as creek beds or gullies.

At upper elevations, a wide range of conditions exist. Dry powdery snow can still be found on north facing slopes. Sun exposed slopes have a variety of crusts that have now been dusted with a skiff of new snow. With a solid refreeze last night, the snowpack will be locked up tight – at least for the morning hours. If the sun does comes out, wet loose avalanches will likely occur on steep-sun exposed slopes. Fortunately, this type of hazard is predictable and easy to avoid.

Cornices: Warming temperatures are gradually destabilizing these massive chunks of snow. Cornices can break farther back than one might expect, so giving them a wide berth along ridgelines is the best way to ensure your well-being.       

Today, generally safe avalanche conditions exist and the avalanche danger is rated LOW. The danger could rise to MODERATE by this afternoon if the sun appears for an extended period of time.

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.

Take Note:

Our 136th and last avalanche advisory will be on Sunday, April 7th

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