RCMP are on scene in the area of the Columbia Icefields after an Ice Explorer all terrain vehicle rolled Saturday afternoon.
Of the 27 people on board, three adults were killed and several others were critically injured.
Mounties say Banff and Lake Louise detachments, as well as area Fire Departments, EMS, STARS Air Ambulance and Parks Canada staff responded due to the remote location and the number of injuries.
Various helicopter companies contracted by Parks Canada transported victims to a triage site where they were then taken to various hospitals by STARS and ground ambulances.
The investigation is in its early stages and RCMP say more updates will be provided as they become available.
Names of the deceased have not been released.
Highway 93 remains open.