Wildfires raging across central and southern Chile on Sunday left at least 18 people dead, scorched thousands of acres of forest and destroyed hundreds of homes, authorities said, as the South American country swelters under a heat wave. Chilean President Gabriel Boric declared a state of catastrophe in the country’s central Biobio region and the neighboring Ñuble region, around 300 miles south of Santiago, the capital. The emergency designation allows greater coordination with the military to rein in over two dozen active wildfires that have so far blazed through 21,000 acres, according to the national forestry agency.