Updated

A blizzard sweeping across the Canadian plains caused a chain of traffic wrecks involving a bus, semi-trailer trucks and cars south of Edmonton, Alberta, sending about 300 injured travelers to hospitals on Thursday, officials said.

Four people were seriously hurt, said Sharman Hnatiuk of the Alberta Health Services office. Many victims were taken to hospitals in nearby communities including Edmonton and Red Deer, she said.

The Royal Canadian Mounted Police closed part of Highway 2, the main road between Edmonton and Calgary, and were directing traffic away from the collision scene, said RCMP Staff Sgt. Grant MacDonald.

He said the crash involved several vehicles, including a large passenger bus and several semi-trailer trucks.