A 21-year-old Rapid City man is dead after a mountain biking accident Saturday afternoon near Rockerville.
The victim had been riding with a friend on a U.S. Forest Service trail near Silver Mountain Road about 3:20 p.m., according to Pennington County Sheriff's Sgt. Greg Foster.
The man's friend said the victim was going down a steep hill when he hit a small rock in the trail, lost control of his bike, came off the bike and hit a tree, Foster said.
The victim suffered a serious head injury. He was pronounced dead upon arrival at Rapid City Regional Hospital.
"It was just a tragic accident," Foster said. He said the man, who was reported to be a very experienced rider, was wearing a helmet.
The identity of the victim is not being released until his family has been notified.