B.C.'s Sea to Sky Highway closed down for about an hour on Sunday afternoon because of a crash.

Drive BC tweeted just after 12:30p.m. that there was a "vehicle incident" near Brunswick Beach, which is just north of Lions Bay.

Witnesses tell CTV News they saw a grey Porsche that had flipped over near a rock wall and come to rest in a ditch.

Witnesses also reported seeing an air ambulance leave the scene.

BC Emergency Health Services told CTV news two victims were transported to hospital in critical condition.

The southbound lanes of Highway 99 were moving slowly by 1 p.m., and the entire highway was clear by about 1:30 p.m.