A young boy is missing and his sister dead after a wave swept the children and their father out into the ocean, Oregon state police say.

The incident occurred Saturday afternoon when Jeremy Stiles, 47, of Portland was at the Falcon Cove area, near the Clatsop and Tillamook county line, with his two children.

State police said Stiles was on the shore holding the children, a 7-year-old girl and 4-year-old boy, when "they were all swept into the ocean by a wave."

A police officer with the Manzanita Police Department responded and saw the man struggling and the girl farther out in the ocean.

The officer was able to get to the girl and bring her back to the shore, state police said. Both she and her father were transported to a nearby hospital, where the girl was pronounced dead.

United States Coast Guard helicopters helped search for the boy, who was still missing Sunday.

A high surf warning had been issued along the Oregon coast over the weekend, the Oregonian reported.

The area around Falcon Cove can be especially dangerous in winter as waves crash onto shore and leave little beach area, KGW-TV reported.

"When you don’t see any beach there, it’s just not a safe place to be. And when you don’t see enough beach or enough area to get away from it, it’s a super dangerous place to be, and that’s the conditions that we’re dealing with right now," Cannon Beach Emergency Manager Rick Hudson told the TV station.