Four people are believed to have been killed in what's described as the worst flooding to hit western Canada in a decade.

The city of Calgary in Alberta has been shut down and evacuated as both rivers running through it overflowed.

Roads and bridges have been washed away and electricity cut-off.

More than 1,200 soldiers were assisting in the rescue and reinforcement operations.

The severe wet weather is being caused by an area of high pressure in Alaska and northern Alberta which has pulled a stream of moisture up into southern Alberta from the United States.