AUGUSTA, Maine (AP) -- At least eleven deaths in the United States are now blamed on a weekend storm that has left areas from the upper Midwest to northern New England covered with ice and without power -- possibly through Christmas.

Thousands of flights have been operating behind schedule -- including many in New York, Washington, Chicago, Denver, Dallas and Houston. And the flight tracker FlightAware says more than 275 flights were canceled.

Delta Air Lines says a taxiway that may have frozen over is suspected in an accident at the Detroit Metropolitan Airport. A jetliner slid onto the grass, but no one was hurt.

Some 400,000 homes and businesses are without power in Michigan, upstate New York and northern New England -- down from Sunday's peak of more than a half million. Most are in Michigan, where utility companies say it will be days before power is restored because of the difficulty of working around broken lines.