Accident: Boss Canyon

Observer Name
Justin Francis
Observation Date
Tuesday, December 26, 2017
Occurrence Date
Tuesday, December 26, 2017
Occurence Time
Afternoon

Region:

Location Name or Route
Boss Canyon, Franklin Basin
Elevation
8500
Aspect
North
Slope Angle
41
Trigger
Snowmobiler
Trigger: additional info
Unintentionally Triggered
Avalanche Type
Soft Slab
Avalanche Problem
Persistent Slab
Weak Layer
Facets
Depth
2'
Width
90
Vertical
450
Carried
1
Caught
2
Buried - Partly
1
Injured
1
Accident and Rescue Summary

Two cousins, experienced riders in a family party, were sidehilling through the forest in lower Boss Canyon. They felt the trees would offer some degree of safety from the known avalanche danger.  When they triggered the persistent slab avalanche, both riders were caught, but one was able to ride clear of the flank of the avalanche. The other was caught and carried through the trees. When he was caught, the 20-year-old rider immediately deployed his avalanche airbag and held tightly on to his sled as he was swept downhill into a large tree, his ankle pinned between his sled and the tree. The heavily damaged snowmobile was deeply buried and the rider mostly buried, with just part of his head and airbag sticking visible. It took a long time and lots of digging for the party to get both the rider and his sled extracted.  After about 45 minutes of digging, the slightly injured and very lucky rider was freed, and the party was able to get the damaged sled out of the backcountry and to the Franklin Basin trailhead.

 

Terrain Summary

The avalanche occurred on treed north facing slope in mid-Boss Canyon at around 8500' in elevation.  The riders were under the impression that avalanche conditions would be safer in the trees than on open slopes.

Weather Conditions and History

Two moist storms ending of Christmas Day deposited 25" of snow and almost 4" SWE as measured by the Tony Grove Snotel, about 5 miles to the south of the avalanche site.   Constant westerly winds battered the northern Bear River Range during this time, and a slab was formed on weak faceted snow from the 3-week-long December high pressure system.

Snow Profile Comments

Profile from crown of avalanche on 12/28/17

Comments

http://unofficialnetworks.com/2017/12/29/utah-snowmobiler-digs-brother-out-of-avalanche-credits-avalanche-airbag-for-survival/

From Fox 13 news story:

A snowmobiler was saved by his brother after getting buried in a football field sized avalanche near the Utah-Idaho border near the Franklin Basin of Logan Canyon this week. FOX 13 SLC reports the buried snowmobiler was found by his avalanche airbag which he had deployed in the slide:

“I called over the radio and said, “Avalanche. Avalanche. Trace was buried. When I finally saw the airbag and it was against the tree, I just, I mean: Worst case scenario is what comes to mind. I started running towards him, he’s only 50 yards away from me up the hill, but with that deep of snow it felt like it took me an hour to get to him. He kept saying, ‘hurry, hurry my leg,’ and we couldn’t dig fast enough. Time stood still. Everything we did just seemed too slow.”

After a 45 minute struggle, Trace’s brother and uncle we able to free him and while his snowmobile was crushed, Trace was thankfully uninjured. Trace’s brother credits the airbag for his brother’s survival:

“We would not have found him. He would have been completely buried. That [avalanche air bag] is what saved his life. He would have been completely under.”

The Utah Avalanche Center wants to remind us to always check conditions before recreating in the mountains and to ensure you have the right gear. The Francis family expressed their sincere gratitude for those at the Utah Avalanche Center and the work they do. For more from the Utah Avalanche Center go HERE

Comments

Email from buried rider's mother:

"Hi, the avalanche at Boss Canyon yesterday involved my son.  I am so thankful for the countless hours they spend in your classes learning and observing.  Thankful for proper gear and for the outcome of this event.  His brother and dad and uncle are the ones that dug him out.  So many mixed emotions as they were digging him out and can't imagine how they would have felt had he not made it.  THANK YOU THANK YOU THANK YOU!"

Comments

Looking down the avalanche path is pretty scary!

I made the Steep Hollow video not far away on the same day the avalanche occurred.  Unstable snow was widespread, the avalanche danger was HIGH and and we had continued an Avalanche Warning. 

Video
Video
Coordinates