“At approximately 2200 hours [06:00 GMT Sunday], Alaska State Troopers were notified of an overdue helicopter and the location of possible crash debris in the area of Knik Glacier. … The rescuers found a sole survivor at the crash site and transported the individual for medical care; the survivor is currently in serious but stable condition. Five other occupants of the helicopter were found deceased,” the authority said in a statement.

It added that the National Transportation Safety Board was investigating the cause of the crash.