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Canada floods: Roof collides with bridge

21 June 2013 Last updated at 22:14 BST

Amateur footage has captured the moment a roof collided with a bridge as it was washed down stream in Bragg Creek, Alberta.

It came as authorities ordered the evacuation of downtown Calgary, Alberta's largest city, where flooding has left swathes of the city underwater.

Torrential rain and floodwaters have washed away roads and bridges and caused landslides elsewhere in the province.

Footage courtesy Tristan Zaba