Holding the top spot for just 227 days, the Thomas Fire, which burned 281,893 acres across Ventura and Santa Barbara counties this past winter, was surpassed on the evening of August 6 as the Mendocino Complex Fire became the biggest wildfire in modern California history, according to 90 years of Cal Fire record keeping. The Mendocino Complex conflagration began on July 27 as a pair of neighboring blazes, the Ranch and the River fires. Operationally, however, they are being fought together under a single incident-command team. As of Wednesday morning, the wildfire had burned 300,086 acres in Mendocino, Lake, and Colusa counties; containment was at 47 percent.
Cal Fire records do not date back to the Santiago Canyon Fire of 1889, estimated to have burned more than 300,000 acres across Orange, Riverside, and San Diego counties. Conditions leading up to that late-September blaze were marked by severe drought, nearly nonexistent spring and summer rainfall, and several Santa Ana windstorms that further desiccated an already parched landscape.