Good Morning. This is Eric Knoff with the Gallatin National Forest Avalanche Advisory issued on Saturday, February 18th at 6:45 a.m. Today’s advisory is sponsored by Yellowstone Club Community Foundation and Montana Ale Works. This advisory does not apply to operating ski areas.
Overnight a trace to 1” of snow fell in the mountains around West Yellowstone. The rest of the advisory area remained dry. At 5 a.m. temperatures are in the 20s F and winds are blowing 20-40 mph out of the S-SW. Today, skies will remain mostly cloudy and highs will warm into the upper 20s to low 30s with the exception of the Bridger Range where highs will climb into the low 40s. Winds will remain moderate to strong out of the S-SW. There is a chance for snow showers in the mountains around Cooke City and West Yellowstone. These areas should see 2-3” by tomorrow morning.
A good freeze overnight will keep the snowpack locked up today on mid to low elevation slopes. This will eliminate the wet snow avalanche hazard. In upper elevation terrain, the snowpack still has lingering instabilities. In the mountains near Big Sky and West Yellowstone, a thin layer of facets buried 1.5-2’ deep still exists. This layer has gained strength over the past week, but should still be looked for and assessed before committing to avalanche terrain.
In the mountains south of Big Sky, a few inches of new snow combined with strong SW winds will create small wind slabs below leeward ridgelines. These will only present a real hazard if triggered in steep, high consequence terrain.
In the mountains around Cooke City, the snowpack is generally deep and stable. However, strong winds out of the W-SW have likely created fresh wind slabs on upper elevation, leeward slopes. These have the potential to fail under the weight of a skier or rider. Persistent weak layers are not widespread around Cooke City, but weak-faceted snow does exist in isolated areas. If a slide does fail on a buried weak layer, it will likely be large and dangerous.
Although avalanches are becoming harder to trigger, now is no time to let your guard down. If you’re out skiing or riding this weekend – carry proper rescue gear, only expose one person at a time to avalanche terrain and always watch your partner from a safe location.
Today, human triggered avalanches are possible and the avalanche danger is rated MODERATE.
Northern Gallatin Range Bridger Range
The Bridger Range and northern Gallatin Range have the least amount of snow in the advisory area. These ranges have been heavily affected by warm temps and strong winds. On Thursday, Alex and I skied Mt Blackmore in full combat conditions. While skiing quality was terrible, stability was good. We did observe one recent avalanche on the north face that was triggered by a cornice drop (photo). This is a good reminder that cornices and slopes directly below cornices still present a hazard.
Aside from a few isolated problems, the snowpack in the Bridger Range and Northern Gallatin Range is mostly stable. One thing to keep an eye on today will be above freezing temps in the Bridgers. This won’t be a problem until the afternoon hours, but it could present a wet snow avalanche danger later in the day.
Today, generally safe avalanche conditions exist and the avalanche danger is rated LOW.
Alex will issue the next advisory tomorrow morning by 7:30 a.m.
We rely on your field observations. Send us an email with simple weather and snowpack information along the lines of what you might share with your friends: How much new snow? Was the skiing/riding any good? Did you see any avalanches or signs of instability? Was snow blowing at the ridgelines? If you have snowpit or test data we'll take that too, but this core info is super helpful! Email us at mtavalanche@gmail.com or leave a message at 406-587-6984.
Beacon Training Park at Beall: Open and free to the public for avalanche beacon practice seven days a week from 9 a.m. to 8 p.m., southeast corner of Beall Park in Bozeman.
COOKE CITY
Today, free rescue training on Lulu Pass Road (Look for the yellow sign).
Bozeman
Today and tomorrow, Bozeman Split Fest - More info here.
March 4, Pinhead Classic, Proceeds to benefit Friends of GNFAC. More info here.