One of the largest fires in California history was sparked by Southern California Edison power lines that came into contact during high winds, investigators said Wednesday.
The resulting arc ignited dry brush on Dec. 4, 2017, starting the blaze in Ventura and Santa Barbara counties that resulted in two deaths and blackened more than 440 square miles (1,139 square kilometers), according to the investigation headed by the Ventura County Fire Department.
The arc "deposited hot, burning or molten material onto the ground, in a receptive fuel bed, causing the fire," said a statement accompanying the investigative report.
Investigators said the Thomas fire first began as two separate blazes started about 15 minutes apart that joined together. They determined Southern California Edison was responsible for both ignitions.