LOS ANGELES (REUTERS) - A four-year-old boy on a family hike on California's scenic northern coast fell 70m down an oceanside cliff but managed to survive and was conscious when rescuers reached him on the rocky shore below, a fire official said on Tuesday.

After the fall off the scenic promontory on Monday at Bodega Head State Park, two paramedics were lowered in a metal basket by ropes and found the boy crying, suffering bone fractures and major injuries, Bodega Bay firefighter Lou Stoerzinger said.

Rescuers were relieved when they found the boy alive, he said, although he could give no information on the child's current condition or longer-term prognosis.

"It felt pretty good, it's one we can put in the win column," Stoerzinger said. "There's a lot of factors that go into working rescues and yesterday luck was definitely on our side."

It was unclear if the child bounced along the steep cliff face of limestone and sandstone or if he fell through air during the whole drop, but there were no tree branches to break his fall, he said.

An airlift helicopter was unable to land in the area, about 82km north-west of San Francisco, because of poor weather and bad visibility, the Sonoma County Sheriff's Office said in a statement.

So the boy was taken to a local hospital by ambulance, it said.

Later on Monday, the child was transferred to Children's Hospital Oakland, Stoerzinger said.

A spokesman for the facility said he could not immediately release information about the boy's condition.

Stoerzinger said he did not know where the boy's family is from.

A representative from the Sonoma County Sheriff's Office could not be reached for comment.