This is preliminary information -

Backcountry skiers and riders out in force today on a particularly active day. An experienced team skinned up from the upper parking lot at Alta heading for Greeley Bowl and the Gunsight Notch. One of the team triggered and was caught in a slide he triggered just below Gunsight, carrying him down 500'. Initial reports had an injury of a fractured or dislocated pelvis but this was later adjusted to a fractured femur. He and his party and then the Alta Ski Patrol worked to get the injured skier out to the road (with the potential of others out kicking other avalanches down upon them.)

Photos below of similarly triggered soft slabs - most 10-16" deep perhaps 100' wide or so - all in terrain with weak preexisting snow - roughly 9500' and above at northwest through east facing terrain.

Many of these were triggered remotely and then sympathetic'd other similar soft slabs.

Comment from a witness to the event -

Same report given earlier but fleshed out a little. Party of four approached gunsight as stated in prelim report. One of the party decided to enter from lower on the ridge rather from the top. Another party of four joined at the top making seven people at the top and a single skier down the ridge. While getting ready at the top, the party of seven witnessed a significant slide enter gunsight from the right where the lone skier was. After some verbal communication, it was established he was safe. (Apparently he dropped off the ridge and immediately set off a slab, although caught briefly, he skied diagonally to a safe spot). A few skiers from the party of seven initiated several ski cuts and major stomping at the top. Evidence of a pre-existing 6-8" fracture ran along the left side of the chute for several hundred yards so it appeared as if the chute had already triggered. The first skier from the party of seven descended down the chute and stopped in the trees on the right side of the chute well below the rope line that demarcates Eddy's High. Upon stopping, the first skier triggered a small sluff beneath him on the more westerly aspect of the chute. He watched as the lone skier approached to his general location and then skied out the chute exiting to the left towards Greeley Hill. The next skier left from the top and again skied the main part of the chute and after a brief fall, also descended the chute past the first skier (who was still in the safe spot in the trees) and descended out the chute to the left. Third snowboarder descended the main chute on the left into the debris from the previous avalanche and again exited at the bottom on the left. At this point, two skiers and one snowboarder had skied the chute and one skier had entered the chute from the left (after the avalanche) for a total of four skiers down below (three below on the left out of the chute and one in the trees on the right shoulder). Fourth skier from the top entered the main chute and skied to the right towards Eddy's High. Soon after, a slab released above him and catapulted him forward as it entrained him on its way down the chute. Victim was carried for 600' to 900' (not sure of distance but more than 400'). He was actively trying to swim and stay towards the top. Near the end of his ride, victim noticed light off to his left and somehow made his way to the surface. None of the witnesses could see him after he was initially swallowed by the avalanche, but as the dust settled he ended up almost completely out of the snow head up and facing down hill. The basin immediately erupted in chaotic yelling as dozens of other people witnessed the avalanche. The three previous skiers quickly skied down to him while another went to get help. The three remaining from on top descended the chute and arrived on scene shortly after. It was quickly established that victim did not lose consciousness, had strong vital signs, and chief complaint was severe pain in the left hip. 911 was called immediately who relayed the info to Alta Central and stayed on the line with the rescue. While the party as well as several helpful witnesses worked on stabilizing the victim, another avalanche further west on Greeley released and ran full track. It was quickly apparent that more skiers were on the ridgeline and unaware of the rescue occurring below. A handful of the party remained and moved the victim out of the slide path to a safe spot above Suzy's tree using the snowboard as a makeshift sled. Several people from other parties volunteered their warm gear, puffys, mittens, and even some tea while party waited for Alta Patrol to evacuate the victim. Approximately 75 minutes later, Alta Patrol picked their way through sketchy conditions and arrived on scene with a sled. Victim was transferred to the sled in an upright position and descended to Albion Basin then transported to the hospital in an ambulance. Victim suffered a fractured femur at the top of the ball joint. Kudos to Alta Patrol for not only making it to the victim under dicey circumstances, but doing so pre-season short-staffed and in the midst of what turned out to be an all around highly active day. Many thanks to the other parties who offered warm gear, support, and pain suppressants.

Other witness -

Witnessed 3 avalanches in less than 30 minutes. The first was released by the first of many people to drop into Gunsight Coulior. It ran to the bottom without carrying the skier. Then several more people dropped in, sometimes two or three riding at once. About the 5th person to drop in released a bigger slide that carried him to the bottom. Members of his party reached him quickly and shouted to call 911. As the injured waited for help, people continued to drop in and ski down directly above. Shortly after (while the injured was still waiting for help) a snowboarded dropped in 50 yards downridge (North) and released a soft slab that ran over a cliff band and into some small pine trees - luckily not carrying the rider. A second rider dropped in and rode to the first rider. Both continued down without any additional incidents. We did not travel into the danger area to get better details on the slides, but the activity we were witnessing seemed downright suicidal. When we left there were still people hiking up the ridge and preparing to ride the same or similar slopes.