Accident Report          Forest Service Utah Avalanche Center

Saturday, February 17, 2007

Western Uinta Mountains- One snowmobiler caught, buried and killed.

Accident Report by Craig Gordon 02-18-07 21:00

Location:

The avalanche occurred shortly after 16:00 on Saturday Feb.17th in Buck Basin which is about 3 miles east-northeast of Tower Mountain a very popular snowmobiling area, east of the town of Heber, Utah.

Lat/Long- N 40 23.603 W 111 08.381

http://www.topozone.com/map.asp?lat=40.3922&lon=-111.132&datum=nad27&u=4&layer=DRG&size=l&s=50

Accident Summary and Rescue Summary: (Click HERE for photos)

Five young snowmobilers, four males and one female (16-19 years old), began their day snowmobiling in the terrain surrounding the accident site. Most of them were wearing avalanche rescue gear, though those details are still being sifted through. Many clues to instability were missed along the way, including natural avalanches close to the accident site. In addition, at least one large hard slab avalanche was triggered without incident, about a ¼ mile north of the accident site prior to the fatality. This slide was 2’-3’ deep, 250’ wide, running about 150’ vertically. It most likely emboldened the group, luring them deeper into the avalanche dragons den. This group was very familiar with the terrain and had triggered small avalanches in the area on past outings.

Around 16:00 the group traveled to the southwest of the avalanche they just triggered and regrouped at the bottom of a south facing slope. Several riders climbed the 32 degree slope above them without incident. Sixteen year old Zachary Holmes began climbing the slope too, but when he neared the top, he began “side-hilling” towards a steeper adjacent slope which had more of an easterly aspect. As he changed aspect and slope angle, he triggered a large hard slab avalanche 2’-4’ deep and 300’-325’ wide.

His partners turned their beacons on to receive and began searching. There was plenty of confusion and several random holes were dug 75’ uphill from where Zachary was finally located, buried 3’ under his snowmobile which was sticking out of the snow. After he was found, two young men stayed on the scene and began CPR while a male and female rode back to the trailhead to make a cell phone call and alert local authorities. Much to their dismay their phones didn’t work at the trailhead, but a family with an “OnStar” system in the vehicle placed a call and Wasatch County Search and Rescue was dispatched.

Back at the scene, as the older brother performed CPR an Airmed helicopter located the accident site and dropped a flight nurse off at the scene. Zachary was flown to a local hospital where he died of traumatic injuries.

Avalanche Data: 

The avalanche was a pencil hard slab 2’-4’ deep, 300’-325’ wide, running approx 250’ vertically. It would be classified as a HS-AM-D2-R4-O

Weather History: 

The western Uinta snowpack is usually plagued by cold temperatures, shallow snow depths, very weak snow and strong winds. This year has been particularly grim and Snotel sites near the accident reveal snow and water totals are about 65% of normal. Like much of Utah the storm track hasn’t been kind to the state this winter, but a series of storms began to affect the region beginning Saturday Feb. 10^th. A strong system hit the area depositing 10” of new snow with an inch of water and strong west-northwest winds. While it was a big hit to the fragile snowpack, many slopes didn’t avalanche. Another system slammed into the region Friday Feb.16^th depositing 6”of dense snow and strong northwest winds averaging in the 30’s, gusting into the mid 50’s for several hours on the night of the 16^th. Saturday Feb.17^th dawned clear with light winds. The avalanche danger was rated CONSIDERABLE and I made special mention to how tricky avalanche conditions would be in the wake of the storm and to think about the consequences of triggering an avalanche as they would be dangerous and possibly unsurvivable. Unfortunately, not everyone heeded the advice.