"This is a tragedy beyond words," said Inspector Tim Shields, regional duty officer with the Royal Canadian Mounted Police.
Police say a Jeep Cherokee with Washington state license plates was traveling north, bound for Whistler, when it crossed the center line and hit an oncoming Chevy pickup truck Saturday morning.
The truck driver suffered minor injuries and walked away from the crash, but two of four 19- and 20-year-old women in the Jeep were killed.
Two of the women in the vehicle were Canadian and the others were American, but police said they had not yet confirmed the identities and nationalities of the pair who died in the accident.
Shields says one of the survivors is in stable condition at Vancouver General Hospital and one is in very serious condition.
There were reports of ice in the area but investigators are not sure if that was the cause, Shields said.
The highway was expected to remain closed until at least the early evening at the scene of the crash near Lions Bay, north of Vancouver.