Look closely where the lightning meets the water. Tiny bolts appear to be dancing around the impact site.
"Those are called 'upward streamers,'" says lightning expert Richard Blakeslee of the NASA Marshall Space Flight Center. "In a typical cloud-to-ground lightning strike, as the leader approaches the ground, the large electric field at the leader tip induces these upward propagating streamers. The first one that connects to the downward propagating leader initiates the bright return stroke that we see with our eye. Upward streamers are often observed on photographs of lightning hitting the ground."
Now we know they can be seen when lightning hits the water, too.
Schaefers and Burger took many pictures that night, mostly from underneath a balcony where they figured the lightning wouldn't reach. This favorite is called The Cruise You Don't Want to Take.