Firefighting efforts at the Thomas Fire in Southern California turned somber on Thursday following the death of a San Diego firefighter. A crew from the Mohave Valley Fire Department is among the 8,100 firefighters assigned to the blaze in Ventura and Santa Barbara counties. “I am very saddened to report that a firefighter fatality has occurred on the Thomas Incident,” said Chief Ken Pimlott, the director of the California Department of Forestry and Fire Protection, said in a statement. “Please join me in keeping our fallen firefighter and his loved ones in your prayers and all the responders on the front lines in your thoughts as they continue to work under extremely challenging conditions.” Pimlott said Cory Iverson was an engineer based in San Diego. Iverson had been with the California Department of Forestry and Fire Protection since 2009.