Avalanche Accident Report          Forest Service Utah Avalanche Center

Preliminary (updated 10:30am Dec 27)

 

Tuesday, December 25, 2007

 

Western Uintas – Superbowl near Windy Ridge – Male snowmobiler caught, buried and killed in avalanche

 

History: Because of its long arduous approaches, snowmobilers are the predominate user group in the western Uinta Mountains. A grant from Utah State Parks and Recreation in the winter of 2003-04 allowed funding for a part-time weekend avalanche forecast program. Longer term funding was eventually established and now advisories are issued on the busiest days of the week- weekends and holidays with an additional midweek update on Wednesday. Since 2001, there have been six avalanche fatalities involving five snowmobilers and one skier, but each year there are many close calls that we never hear about.  

 

Location: The avalanche occurred midslope in steep, heavily wind loaded terrain, facing east-northeast. (Click HERE for a photo.) The location is known by locals as the Super Bowl, east of Windy Peak in Moffit Basin.  (Click HERE for an aerial view.)

 

 

Accident and Rescue Summary: Details are still being sifted through, but what we know is this- a group of six male snowmobilers left the Smith-Moorehouse trailhead, near 1000 Peaks Ranch for an afternoon Christmas ride at about 13:00. They climbed the terrain surrounding the ranch, playing in low angle meadows before ascending Windy Peak and dropping into the Super Bowl. There’s conflicting stories as to how the victim became buried, but at approx. 15:30 a phone call to 9-11 was placed and a search ensued. A Summit County Search and Rescue team found the man at approx. 17:30 with an organized probe line. He was not wearing a beacon, but some members in his party had beacons, shovels and probes.  

 

 

Avalanche Data: The avalanche averaged 3’-4’ deep, was close to 1000’ wide and ran approximately 350’-400’ vertically, classified as a HS-AM-R4-D2-O. This slide failed at the ground on a depth hoar/melt-freeze crust interface, developed in October. (Click HERE for snowpit profile.)

 

 

 

Terrain: Super Bowl is a common destination for riders who access the terrain from both Evanston, Wyoming at the Bear River trailhead and from Utah’s 1000 Peaks Ranch. A guided snowmobile operation also operates in the vicinity.

 

 

 

Weather and Snowpack History: The western Uinta snowpack is historically plagued by cold temperatures, shallow snow depths, very weak snow and strong winds… this winter is no exception. An active weather pattern in October, deposited early season snows above 9,000’ and it looked like a banner start to the season. The storm track shifted north and the western Uinta’s were left high and dry throughout November.  The first in a series of storms began moving into the region on Dec. 1st, depositing 12” of snow, followed by a slightly stronger system on Dec. 7th. New snow totals averaged 14” in the area the accident occurred and gusty southwest winds accompanied this storm. An avalanche watch was issued on the 7th describing an overall danger of CONSIDERABLE in upper elevation wind loaded terrain. Clear, cold weather following this storm allowed near surface facet development.  A vigorous storm system on the 21st stacked up an additional 16” of snow and warranted issuing an avalanche warning as high winds and heavy snow created a HIGH avalanche danger on steep northerly facing slopes. A natural, albeit pockety, avalanche cycle occurred during the storm. The 22nd dawned clear and cold and with new snow on a weak pre-existing snowpack, we knew all the ingredients for an avalanche accident were aligning. Two snowmobile triggered avalanches occurred in the southern half of the range and probably many more that we didn’t hear about, but no serious incidents were reported… we dodged a bullet. Another storm rolled in on Christmas Eve delivering 8” of very light density snow, but west and northwest winds gusting in the 50’s along the ridges accompanied the system. The avalanche advisory posted on Dec. 25th called for an overall CONSIDERABLE avalanche danger on steep, upper elevation slopes and specifically mentioned there were pockets of HIGH danger on these same slopes where wind drifts were present. In addition, the advisory mentioned “the possibility of triggering a deep, scary avalanche that breaks into weak snow near the ground still exists, especially in steep, upper elevation terrain facing the north half of the compass”.

 

 

Media Links:

http://www.deseretnews.com/article/1,5143,695239241,00.html

http://www.ksl.com/?nid=148&sid=2387838

http://www.upi.com/NewsTrack/Top_News/2007/12/26/utah_avalanche_kills_father_of_six/1376/

http://www.sltrib.com/news/ci_7809554