A teenage boogie boarder was missing off the Oregon coast and presumed dead, while his father was found dead after jumping in the water to save his son, U.S. Coast Guard officials said Wednesday.

Helicopter crews were still looking for the 17-year-old, whose stepmother alerted authorities after losing sight of her family members from Rockaway Beach, west of Portland, the Coast Guard said.

Witness Vickie Gross told Fox 12 Oregon that the scene was "frantic," as she watched from the balcony of her condo near the beach.

"A 911 vehicle went by going north on the beach and stopped," Gross told the station. "I opened the door 'cause I could hear voices and stuff. ... The gentleman climbed out of that little van and got on top with his binoculars and started peering out into the water."

The family was visiting from Fort Collins, Colo., Fox 12 reported.

The 50-year-old father was found around 45 minutes into the search, but did not survive, authorities told the Oregonian.

Oregon State Police told Fox 12 that the teen was riding his board in the surf when he was knocked off by a wave.

Officials told the station that the teen was presumed dead.

The names of the father and son were not immediately released.

The Associated Press contributed to this report.