Cal Fire Battalion Chief Rob Van Wormer, a Jamestown resident, died in Santa Cruz on Saturday night while on assignment, according to Cal Fire officials.
Van Wormer worked in Cal Fire's Santa Clara County unit. He was in Santa Cruz working on an investigation.
The 47-year-old lost consciousness while at a restaurant with a friend, officials said.
Cal Fire director Ken Pimlott said numerous attempts to revive him failed.
He was transported to the Dominican Hospital in Santa Cruz, where he was pronounced dead of natural causes around 8 p.m., according to Cal Fire.
No additional information about the cause of his death was released.
"This is a huge loss for Rob's family, his many friends, his Cal Fire family and the fire service as a whole," Pimlott said.
He directed Cal Fire facilities to immediately lower their flags to half-staff and asked all uniformed personnel to shroud their badges until the conclusion of his memorial services, which will be announced at a later date. Van Wormer was a 24-year Cal Fire veteran.
"He has a long history of doing some pretty high-profile fire investigations, and also has a long history in the Cal Fire air program," said Angela Bernheisel, a Cal Fire spokeswoman in Santa Cruz. "He touched a lot of people and was just one of those incredibly likeable guys."
In a statement Monday, Gov. Jerry Brown said, "We extend our deepest condolences to Rob's family, friends and everyone at Cal Fire during this time."
Van Wormer is survived by his parents, Sharon and Ken, his wife Jennifer and his sons Austin and Dalton.
He is also survived by his sister Debbie and his brother Kirk, a Petaluma resident and Cal Fire battalion chief.
Van Wormer's wife could not be reached for comment Monday.