The October 2017 Northern California wildfires, also known as the Northern California firestorm, North Bay Fires, and the Wine Country Fires were a series of 250 wildfires that started burning across the state of California, United States, beginning in early October. Twenty-one became major fires that burned at least 245,000 acres.
The wildfires broke out throughout Napa, Lake, Sonoma, Mendocino, Butte, and Solano Counties during severe fire weather conditions, effectively leading to a major red flag warning for much of the Northern California area. Pacific Gas and Electric reported that red flag conditions existed in 44 of the 49 counties in its service area. Seventeen separate wildfires were reported at that time. These fires included the Tubbs Fire, the Atlas Fire, Nuns Fire, and others.
These wildfires were also the most destructive ones of the 2017 California wildfire season.