Cleanup efforts began in Texas on Tuesday after tornadoes ripped through the Dallas-Fort Worth area, tossing tractor-trailers like toys, forcing airlines to cancel flights and causing widespread damage. In Lancaster, Texas, south of Dallas, roofs were stripped to bare plywood and houses were speared by flying two-by-fours. About 300 buildings were damaged, according to the city’s mayor. A citywide curfew was put in place, and a shelter was opened.