SFGate.com is carrying this AP story:

San Clemente surfer takes brief ride on a whale

Spyros Vamvas caught more than waves on a recent surfing trip.

The 60-year-old San Clemente therapist felt the ocean swirl under him and was lifted up, but when he looked down, he realized it wasn’t the water he was riding — it was a whale.

“All of a sudden I just felt, wow, this huge noise and bump,” said Vamvas, “and it lifted my board up. I’m looking down, and there’s just swirling water and I see barnacles on the back of the whale. I’m used to dolphins. This was different. It was huge.”

The article doesn’t mention the species of whale, but given the location I’m thinking it may have been an Orca.