EUREKA (CBS / AP) -- Howard Kuljian and his family were out for a walk on a damp, overcast morning at Big Lagoon beach, playing fetch with their dog Fran as 10-foot surf churned the water just feet away like a washing machine.

Signs near the beach warned of “sneaker waves,” the kind that suddenly roar ashore.

Kuljian tossed a stick that took the dog down to the water’s edge, and in an instant, authorities said, a wave swallowed it, setting off a nightmarish scramble.