FRESNO, Calif. (AP) — The mother of the CEO of the ride-hailing company Uber died in a boat accident Friday evening in Fresno County, the company said.

Bonnie Kalanick, 71, died after the boat she and her husband, Donald, 78, were riding hit a rock in Pine Flat Lake in the eastern part of the county, authorities said.

They are the parents of Travis Kalanick, 40, who founded Uber in 2009.

uber1 Mother Of Uber CEO Travis Kalanick Killed In Boat Accident

Uber CEO Travis Kalanick with his mother, Bonnie Kalanick. (Kalanick Family Photo via CBS San Francisco)

The couple have been longtime boaters. In a memo to Uber staff, Liane Hornsey, the chief human resources officer, called the incident an “unthinkable tragedy.” She wrote that “everyone in the Uber family knows how incredibly close Travis is to his parents.”

About 5 p.m. Friday, officers were called to the scene of the accident and found a man and woman on a shore of the lake, the Fresno County Sheriff’s office said in a statement.

The woman died at the scene, and the man suffered moderate injuries, the sheriff’s office said. He told officers the boat had sunk.

An autopsy of the woman is planned, the office said.

Uber identified the couple as the Kalanicks. Donald Kalanick is being treated at a hospital and is in stable condition, the company said.

Crews will try to remove the boat from the lake Saturday, the sheriff’s office said.

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