Major cities including New York took unprecedented evacuation measures and were largely spared the full wrath of Irene, which was downgraded on August 28 to a tropical storm as it drenched a vast stretch of the east coast.

But the storm, whose death-strewn trail of carnage began a week ago in the Caribbean, refused to go out with a whimper, ravaging virtually the entire state of Vermont before crossing into Canada.

"We're going to be digging out for a long time. Irene really whacked us hard," Governor Peter Shumlin told Vermont Public Radio.

At the White House, President Barack Obama voiced concern about the flooding in Vermont and other states in the New England region. "It's going to take time to recover from a storm of this magnitude," he said.

The top US disaster official, Craig Fugate, said around five million people remained without electricity, many farther south in states like Virginia, and that it would take "some time to get all of the power back up."

AFP