According to the pilot, night was approaching when he landed the seaplane on a lake and taxied to shore to find out he was at the wrong destination. The pilot then began to taxi along the shore, but then decided to take off again to regain his bearings and land at his intended destination. At the time of the takeoff, night had already fallen, the moon was full, there were no clouds and lighting was flat. Surface conditions were "full glass" with no ripples, and the airplane's navigation lights and landing lights were illuminated. The pilot flew the airplane out over the lake, intending to make a 180-degree turn and land back towards a dock. During the final turn, he lost "visual height reference," and after leveling the wings, he set up for a low-sink-rate, glassy water landing. He thought the airplane was about 100 feet above the water when it was only "mere feet" above the surface, which the airplane impacted at a high speed and a high sink rate. Upon impact, the floats tore off the airplane, which then nosed over. Both occupants exited, and as they were swimming to shore, they were picked up by a boat. The pilot did not note any preexisting mechanical anomalies that would have precluded normal operation. Federal Aviation Administration publication FAA-H-023 states, "night landings in seaplanes on open water are extremely dangerous with a high possibility of damage or loss of the seaplane. A night landing should only be performed in an extreme emergency when no other options are available." It also notes that glassy water conditions can make accurate depth perception very difficult, even for experienced pilots.