In Northern California, firefighters battled the reawakened Park Fire, a massive blaze that re-exploded Monday after several days of slumber and grew by as much as 20 square miles (53 square kilometers), mostly in about 12 hours. The Park Fire, California’s largest so far this year and the state’s fourth-largest on record, had already scorched nearly 647 square miles (1,676 square kilometers) by Tuesday morning. Firefighters were told during their morning briefing to focus on safety and to be mindful of extreme fire behavior including intense and rapidly moving flames. The Park Fire was allegedly ignited by arson on July 24 outside the Sacramento Valley city of Chico, and has destroyed 640 structures and damaged 52.