Three people are killed and dozens injured after a fiery chain-reaction bus crash in Calgary leaves two transit buses ablaze

A Calgary Transit bus slammed into a car on a busy north-end street Thursday, triggering a chain-reaction crash that killed three people and sent 19 to hospital. The stricken bus then bounced through an intersection and struck a parked natural-gas-powered transit bus, setting it ablaze and sending it careering into three more vehicles. Thick smoke billowed over the city as footage showed the second bus burning from roof to front end.

Police Staff Sgt. Andy Woodward, a 36-year veteran, called it 'probably the biggest scene I've worked on in relation to a collision.'

Ten of the 19 injured were taken to hospital by ambulance; a police officer was also hurt and hospitalised.