The man and two of his friends were on the shoreline near the Klamath River in Crescent City, a coastal town near the border with Oregon that has been one of the areas of the state hardest hit by the tsunami, Petty Officer Pamela Manns said.
A tsunami warning was issued for much of the state's coastline early this morning after an 8.9-magnitude earthquake struck off the northeast coast of Japan about 10 hours earlier.
Shortly after 10 a.m., the men were taking photos of the waves when they were swept out to sea by a wave, Manns said.
Two of the men were able to swim back to shore, but the third remained missing as of 12:15 p.m., she said.
Over the course of seven hours, the Coast Guard searched more than 250 square miles of ocean and shoreline using several helicopters and a 47-foot long motor lifeboat dispatched from the agency's Humboldt station, she said.
"The only reason we'd resume the search would be if there were new evidence," Manns said.
The Coast Guard's Sector San Francisco worked closely with both the search in Crescent City and with cases of boats crashing into each other in Santa Cruz.
Officials in Santa Cruz estimate the waves have caused about $15 million in damage at the Santa Cruz Harbor, where several boats became loose and crashed into each other.
Twenty boats sunk and 100 others sustained damage due to the surge, officials said.
No injuries have been reported in the Santa Cruz incidents.
Manns said that despite the waning threat posed by the tsunami, the Coast Guard is requesting that everyone stays away from low-lying coastal areas such as beaches and jetties for the near future.
"You never know when a rogue wave will come along," Manns said. "The waters in Northern California are notoriously treacherous."