Woman Dies of Injuries Suffered in Jet Ski Collision : Castaic Lake: The accident occurs in an area set aside for the craft to avoid crashes with boaters.

A 46-year-old woman riding a jet ski on Castaic Lake died after her sister’s boyfriend rammed into her with another water scooter, authorities said Sunday.

Rita Yung of Foster City, Calif., was taken by helicopter to Henry Mayo Newhall Memorial Hospital, where she was pronounced dead of massive head injuries, said Sgt. Ike Aguilar of the Los Angeles County Sheriff’s Department.

The accident occurred about 4:30 p.m. Saturday in a two-mile-by-300-foot strip of the upper lake that was set aside for jet skiers five years ago because of concerns over collisions with boaters, said Charles Graham, manager of Castaic Lake Recreation Area.

Since the area was roped off, the number of accidents has declined, but one skier lost a leg in a collision with another water scooter last year, Graham said.

“They’re dangerous things, especially in the hands of inexperienced people,” Aguilar said.

Both Yung and her sister’s boyfriend, who was not identified, had rented the water scooters for $35 an hour from a lakeside concessionaire and signed a liability waiver, Graham said.

A lifeguard who witnessed the accident and immediately radioed a patrol boat in the vicinity said the sister’s boyfriend “apparently looked away and by the time he saw her, it was too late,” Graham said.

His jet ski struck Yung and knocked her into the water, Aguilar said.

No charges will be filed against the sister’s boyfriend because the incident was clearly an accident, Aguilar said.