The family was at Big Lagoon, a beach north of Eureka, Saturday afternoon when the dog chased after a thrown stick and got pulled into the ocean by eight to ten foot waves, said Dana Jones, a state Parks and Recreation district superintendent.
Jones said the boy went after the dog, prompting his father to go after them. She said the teenager was able to get out, but when he didn't see his father, he and his mother went into the water looking for him.
"Both were dragged into the ocean," Jones said.
The Times-Standard reports (http://bit.ly/UmSP2P) the couple's daughter called police.
Jones said a park ranger had to run a half mile to get to the beach because his car wasn't made to handle the terrain. When he arrived, he wasn't able to get to them because of the high surf, she said.
Rescuers eventually retrieved the mother's body and the father's body washed up.
The Coast Guard deployed a helicopter and two motor life boats to search for the teenager, but the aerial search was suspended Saturday evening by thick coastal fog.
A call seeking the status of the Coast Guard's search on Sunday wasn't immediately returned.
The dog got out of the water on its own, Jones said.