The Detwiler Fire in Mariposa County, California, grew to 70,000 acres on July 20, as the flames grew unexpectedly overnight.According to Cal Fire, 45 structures have been destroyed and almost 4,000 residents have been evacuated. California Governor Jerry Brown declared a state of emergency on July 18 due to the evacuations and damage to electrical and water infrastructure, the Los Angeles Times reported.Firefighters from Novato, San Rafael, Corte Madera, and Sonoma Counties are helping to fight the fire, as shown in this video. Credit: Novato Fire District via Storyful