Good morning. This is Doug Chabot with the Gallatin National Forest Avalanche Advisory issued on Wednesday, March 25, at 7:30 a.m. Cooke City Bearclaw/Super 8 in partnership with the Friends of the Avalanche Center sponsor today’s advisory. This advisory does not apply to operating ski areas.
Since yesterday morning the mountains got hit with another round of snowfall: 4” in the Bridger Range; 6” up Hyalite; 10” at the Yellowstone Club; 4” in Taylor’s Fork and 2-3” around West Yellowstone and Cooke City. This morning mountain temperatures are in the high teens with winds blowing out of the west at 10-20 mph. Snowfall will taper off in the next few hours and the day will clear before more clouds roll in bringing just a few flurries tonight. High pressure will build over the next couple days with record high temperatures forecasted on Friday.
Bridger Range Madison Range Gallatin Range Lionhead area near West Yellowstone Cooke City
This was our biggest snowstorm since February 21st:
- Bridger Range: 11” snow (1.1” SWE).
- Hyalite/Big Sky/YC: 15-16” snow (1.3” SWE)
- West Yellowstone/Cooke City: 8-10” snow (.6-.7” SWE)
The snow is dense and although the winds have been blowing at the ridgelines, wind-loading has not been widespread. Ski Patrols reported soft slabs being triggered on steep terrain, but on many slopes the storm snow is bonding to the old snow surface: a melt-freeze ice crust on all the but most northerly aspects.
Soft slabs of storm snow and pillows of windblown snow are the main problems today. There is nothing deeper in the snowpack I’m worried about. Loose snow or small soft slab avalanches could be triggered on steep slopes, but generally the new snow fell onto a stable snowpack. Wind-loaded slopes may be touchy since immediately after a storm is when they are easiest to trigger.
The interface between the storm snow and old snow surface is where I recommend concentrating your stability assessment. Since you have to dig no deeper than a foot and a half it should only take a couple minutes to do an Extended Column Test. If it propagates across the entire column go somewhere else to ski or ride. This test is so easy it’s hard to justify blowing it off before saying, “I’m dropping in bro!”
For today the avalanche danger on wind-loaded slopes is CONSIDERABLE. Slopes without a wind-load have a MODERATE danger.
Mark 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.