Good morning. This is Mark Staples with the Gallatin National Forest Avalanche Advisory issued on Friday, April 8, at 7:30 a.m. Montana Import Group, 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 Bridger Range received 6-9 inches of snow with winds blowing 20-30 mph from the NE at the ridge and SE at mid mountain. Most other places received 4-6 inches with winds blowing 10-15 mph mostly from the NE at ridgetops. Winds shouldn’t change much today. Temperatures this morning were in the mid teens to low 20s F and will rise to near 30 F today. Snowfall will continue and an additional 5-7 inches will accumulate by tomorrow morning.
The Bridger Range:
In the last 24 hours the Bridger Range received the most snow and the most wind, and this morning snow was falling at a rate of 1 inch per hour which is rapid loading. Additionally winds have blown from many different directions since yesterday, possibly loading slopes that typically do not receive wind-blown snow. Lots of snow, strong winds, and high snowfall rates are all reasons to expect avalanches in the Bridger Range today. Plenty of good skiing and riding can be found but it requires a careful evaluation of the both the snowpack and terrain. Today the avalanche danger is rated CONSIDERABLE.
The Gallatin and Madison Rangers, the Lionhead area near West Yellowstone, the mountains around Cooke City and the Washburn Range:
Although other areas did not receive as much snow in the last 24 hours, they have received more in recent days. Skiing near Big Sky yesterday, I found a very strong snowpack similar to what we have found in most other areas (snowpits). The primary avalanche concerns exist within the new snow and snow that fell this week. Because weather strongly affects the upper 1 foot of the snowpack, stability can change quickly. Stability can also vary from slope to slope or vary between morning and afternoon. A rapid increase in snowfall or wind, or even a change in the type of new snow crystal can create instabilities. Conversely, once snowfall stops, stability can quickly improve. Even though most avalanches will be confined to newer snow, they can still break several feet deep like one near Cooke City earlier this week (photo). For today, the avalanche danger is rated CONSIDERABLE on all previously wind loaded slopes and MODERATE on all others. As moisture continues streaming into SW Montana, heavy snowfall rates may begin in the southern mountains. If this occurs the danger could rise to CONSIDERABLE on all slopes.
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.
Last Advisory
The last avalanche advisory of the winter is scheduled for this Sunday, April 10th.