A couple made a dramatic escape from a sinking semi-trailer in Cameron Lake on Vancouver Island Sunday morning.

The 45-year-old husband was driving the truck — which was fully loaded with wood chips — and his 49-year-old wife was in the passenger seat when the husband lost control on a sharp corner at Angel Rock on Hwy. 4, said RCMP.

"A very sharp corner, and it looked like the weight of the trailer leaned on to the one side, causing it to lean right over and flip both the tractor and the trailer," said RCMP Cpl. Jesse Foreman.

"At that point there, the lake is extremely close to the roadway and on the other side is a bluff, so there is not a lot of room there," he said.

The truck flipped over a concrete barrier and slid into Cameron Lake, where it disappeared from view. But the couple was able to swim to safety, thanks to a lucky break," said Foreman.

"There was a branch or something that smashed out one of the windows in the cab of the tractor-trailer, allowing them to exit quickly when they hit the water." 

RCMP are investigating the cause of the crash, and the Environment Ministry is looking at whether the semi-trailer can or should be pulled out of the lake, RCMP said.