Mounties have confirmed that a family of four vacationing in B.C. from California was killed in Friday's three-vehicle collision on Highway 93 in Kootenay National Park.

Police said that a couple in their late forties and their two children, a 12-year-old boy and a 10-year-old girl, believed to be from Palo Alto were killed in the collision.

East Kootenay RCMP completed a survey and examination of the crash and subsequent explosion that engulfed all three vehicles in flames. The vehicles were removed late Friday evening and the highway fully re-opened on Saturday.

Cpl. Dan Moskaluk said that the investigation and witness accounts indicate that a southbound flat-deck semi tractor-trailer crossed over the centre line of the highway and into the path of a northbound Dodge camper van towing a Suzuki Sidekick.

The truck and trailer then pinned the van against highway barriers and caused the vehicles to ignite.

Motorists who stopped at the scene were able to assist the truck driver but were unable to help the family of four trapped inside the blazing van.

Moskaluk said that evidence indicated the van tried to avoid the truck by driving onto the shoulder of the road but was unable to avoid the crash.

While it is not known what caused the truck to cross over into the northbound lane, Cpl. Tom Brannigan said that the section of highway could be to blame.

"This is probably one of the worst turns on the entire highway. It has advisory signs all over the place," Brannigan said.

The driver of the truck was detained by investigators and later released without charges.

Police are liaising with U.S. authorities in order to notify the family's next of kin.

Anyone who saw the vehicles prior to the crash or has video footage or photographs is asked to contact the RCMP's East Kootenay Integrated Road Services Unit at 250-420-4244.