Photos

These sides failed on slopes with a similar aspect and elevation. Both were triggered by snowmobilers. Human triggered deep slabs are a major problem around Cooke City right now. Once triggered, deep slab avalanches often produce high consequence situations. Photo J. Kunzman  

This slide occurred on the south face of Mt. Abundance north of Cooke City. The slide was triggered by a snowmobiler climbing the slope. He was caught and buried with only his head sticking out. He suffered two broken legs and was flown by helicopter to the hospital in Bozeman. The slide failed on facets near the ground. Photo B. Fredlund

This natural avalanche was spotted on an ESE aspect on Alex Lowe Peak in Hyalite. Other simiilar slides were seen in the area. Photo: B. Vandenbos

SE aspect at about 9200 feet in the Taylor Fork area of the Southern Madison Range. Weak layers are evident in this photo and they were easily found when digging this snowpack. We found a very thin layer of facets above an ice crust about 1.5 feet deep. This layer formed more recently and shouldn't last too long, nor does it exist on many slopes. A bigger issue are the December facets near the ground. We were surprised how easily these broke in stability tests (profile). Photo: GNFAC

7 riders in the Jefferson's, all wearing beacons and airbags, climbing one at a time on what they considered a small angled slope triggered a pretty deep slide and guy rode it out, ended up on his sled when it stopped. No injuries and no one buried. Photo: J. Watt

7 riders in the Jefferson's, all wearing beacons and airbags, climbing one at a time on what they considered a small angled slope triggered a pretty deep slide and guy rode it out, ended up on his sled when it stopped. No injuries and no one buried. Photo: Damlow

Natural avalanche on Mount Baldy in the southern Bridger Range. Photo: B. VandenBos
 

This natural avalanche is north of Ross Pass.  It ran a long ways and put debris far out of view. Photo: C. Deane

This natural avalanche is near Naya Nuki Bowl and the Throne area of the northern Bridgers. Photo: A. Newman

Debris from this fata avalanche on Crown Butte ranged from 5-15 feet deep and the victim was found 6 feet deep. Live recoveries when people are buried deeper than 6 feet are rare (about 4% of live recoveries are deeper than 6 feet according to the Avalanche Handbook, 3rd Ed.). The debris field extends to the trees in the background. Photo: GNFAC

The debris field from this fatal avalanche was roughly 900 feet by 400 feet....about 8 acres. This photo only shows about 1/3 of the debris. Photo: GNFAC

The locations of the three riders when the avalanche released are shown by the red X's. Dashed lines with arrows show the direction of travel and the escape route used by the two riders who were climbing whent the avalanche occurred. The victim was stopped and unable to escape.

This slide broke in a very thin rocky area. These are likely places to trigger avalanches. Once a collapse (or fracture) in the weak layer starts, it can propagate into much deeper areas. Photo: GNFAC

This weak layer was the weakest snow we have seen all season. Most places have square faceted crystals. This slope had large, cupped, striated, depth hoar crystals up to a centimeter in size. Photo: GNFAC

This slope had very thin snow considering the nearby Fisher Creek SNOTEL has over 10 feet of settled snow. This thin snowpack led to the formation of very weak depth hoar (6-10mm in size and Fist+ hardness). Photo: GNFAC

The snowmobiler was recovered here.  He was not wearing a beacon and found with a probe strike 2+ hours after being buried. Photo: S. Walsh

This avalanche ran full track and buried and killed a snowmobiler outside Cooke City. Photo: B. Zavora

This avalanche, along with others, were seen up Hyalite during the Avalanche Warning on 3/12. It's located below an unamed peak between Maid and Divide.  This ran to the creek. Photo: B. VandenBos

Although Mill Creek in the Absaroka Range is out of our advisory area, this avalanche from Sunday, March 9 is impressive.  If you ski in these areas you will be especially interested.  This is a direct quote from an email: "We triggered this slide in the flats above the ridge from about 5 ft away from the slope in the center of the photo where the trees meet the horizon. The slide initiated on an ice crust below a hard wind slab. The crown was 3 ft deep then stepped down to facets above the rocky ground. The slab was cohesive enough to pull 3 to 4 ft into the flats where we were standing (luckily far enough back not to go with it). It propagated through all the gullies in the bowl North to East facing. I didn't dig a pit at the crown, but did on the same slope, same aspect near the toe of the debris about 800ft below the crown. Results ECT30. In fact, the column stayed together even after toppling it over. We weren't planning on skiing this face because there were numerous recent slides on all N to E facing slopes on all the mountains from Emigant to Knowles."  Photo: K. Konz

This massive slide occurred on the noth side Sctoch Bonnet Mountain north of Cooke City. It is uncertain whether this slide was human triggered or a natural, but judging by the tracks it appears to be snowmobile triggered. The crown looks to be close to 1000 ft. wide and over ten feet deep. Photo S. Walsh