Nine-year-old Tiffany Thrasher was unconscious but breathing when the rescue team arrived on the scene at about noon.
"She hit her head on a big bump and then about five kids ran into her," said her foster brother Devon Lafferty, 12.
Thrasher and Lafferty were taking part in an Inukshuk Ventures Day Camp sledding trip with about 34 other children.
Her 12-year-old cousin Bradley Nind, also a camp participant, had tears well in his eyes as he watched the emergency workers load her into a toboggan before transporting her up the hill to a waiting ambulance.
"I don't know what I'll do if she's not OK," he said.
Amy O'Connor, the camp counsellor who called in the emergency on her cellular phone, couldn't say exactly what happened to the girl.
"I wasn't here at the time it happened," she said. "I called as soon as I got back."
Thrasher was treated and released at Stanton Territorial Hospital.