According to the U.S. Coast Guard, Mary Elena Scott, 57, and her husband Howard Kuljian, 54, were walking along the shore of Big Lagoon beach near Orick with their 16-year-old son Gregory "Geddie" Kuljian, their daughter Olivia Kuljian, and the family dog, when the latter entered the water to fetch a stick.
A 10-foot-swell suddenly appeared and carried the dog into the ocean, prompting Geddie to chase after it.
Sean Ledwin, who witnessed the incident along with his girlfriend, said Geddie managed to grab hold of the dog's collar, but it slipped off, and the teen was soon overtaken by the waves as well.
After Ledwin's girlfriend phoned 911, Scott attempted to seize an opportunity to grab her husband, but the waves proved too strong for her and she was quickly pulled under.
The daughter sought to jump in after her mother, but Ledwin says he stopped her.
Eventually an unconscious Scott washed ashore, but efforts to revive her proved futile. Kuljian's body was found later at another spot; Geddie's body remains missing.
The dog, meanwhile, managed to swim back to the beach on its own, and is currently in the care of a neighbor.