A massive California wildfire has prompted evacuation orders and a highway closure. The Madre Fire ignited Wednesday afternoon in San Luis Obispo County, according to Cal Fire. It has since grown to 79,936 acres and is 30% contained as of Sunday, fire officials said. The fire — the largest in California so far this year, according to Cal Fire data — is burning in a largely rural area in the Los Padres National Forest near Highway 166, officials said. Evacuation orders were issued near Highway 166 in San Luis Obispo County. The highway is closed from U.S. 101 near Santa Maria to Perkins Road in the New Cuyama area of Santa Barbara County, according to the California Department of Transportation. …Approximately 50 structures are threatened, according to Cal Fire. Officials warned that the fire has a high rate of spread.