Police are joining forces with the military to launch an aerial search-and-destroy mission against B.C.'s marijuana crops.

The annual eradication operation will use helicopters to locate and access illegal plantations on Vancouver Island and nearby islands, said Const. Darren Lagan of the RCMP drug and organized crime awareness service.

The raid is being conducted by the RCMP, Saanich Police Department, Victoria Police Department and Canadian Forces. Lagan said he did not know if a similar program was in place on B.C.'s mainland.

Lagan said an outdoor marijuana plantation typically dwarfs many indoor grow-operations with its scale and sophistication.

"This is generally not a mom-and-pop operation, so to speak," he said. "We strongly believe that a majority of them are tied to organized crime."

Some contain up to 500 plants, often growing in patches of 50 to 100 to make detection difficult.

But they're not too hard to spot from a helicopter, Lagan said.

"When you're up in the air, you can really see the difference in colour [against surrounding vegetation]. It's a very vibrant green," he said.

The Canadian Forces will help police reach remote sites, some of which are in forests or beyond waist-deep swamps. Last year, 10,000 plants were destroyed and Lagan said the operation is on target to better that this year.