Drivers were being warned to expect major delays and congestion, after Highway 99 was temporarily closed at Porteau Cove Road due to a serious crash Tuesday evening.
Squamish RCMP said it happened at about 4:45 p.m., and involved two vehicles.
BC Emergency Health Services says two people were transported to hospital, one in serious condition, and one in stable condition.
At least one person was initially trapped in a vehicle, police said.
DriveBC said it would provide an update on the closure at 7 p.m.