WASHINGTON, March 2: Authorities were digging through the rubble of a Georgia high school on Friday, cleaning up from a string of tornadoes spawned by a winter storm that killed 22 people in the US and Canada.

The massive storm system was headed north where it was expected to turn from thunderstorms to blizzards and dump up to 30 centimetres of snow in the north-eastern US, according to the National Weather Service.

The service said it had received reports of 31 tornadoes touching the ground around the region as US media showed images of roofless homes with blown-out windows, uprooted and shredded trees, dangling power lines and cars overturned and crushed.

President George Bush, who was fiercely criticised for a slow response to Hurricane Katrina in 2005, was to tour the devastation on Saturday, the White House said in a statement.

In Alabama, 10 people were killed, including eight teenagers hit when a tornado struck a high school in the town of Enterprise, the state emergency management office said.—AFP