Three fireballs moved slowly along the beach, then suddenly accelerated and flew straight up into the night sky and disappeared.

I was walking on the beach in a remote section near the orange river inlet. It was after dark. The tide was low. I looked out to sea where the breakers were visible in the moon. Suddenly I saw three large fire balls, lined up in a row parallel to the breakers. They were the size of a house each, moving very slow along the beach.
 As the first fireball reached a point, it suddently accelerated rapidly, left to right, and moved 90 degrees up, into the night sky. As each of the other two fireballs reached this approximate location, they, too, accelerated rapidly and moved 90 degrees up into the night sky and disappeared (growing smaller and smaller until I couldn't see them)  Hard to judge speed, but I would guess hundreds of miles per hour once they started to move up into the night sky.
 I was frightened and turned to head back to my house and litteraly bumped into a strange man standing on the beach. He didn't look at me. Stared at the fireballs. Said in a detached way, "Ball lightening. It was ball lightening."  I ran home and have never forgotten that vision.
Witness indicates that date of sighting is approximate.  PD