Razor Reef is an everlasting storm surrounding the island of Dinotopia. While island hopping, Karl, David, and Frank fly into Razor Reef. The boys wash up on the shores of Dinotopia, while their father swims into Diamond Cave.
During the series, Frank, longing for his old life, attempts to cross the reef with Karl and Marion. However, the current is still too strong as they end up back in Dinotopia.
In the episode "Temptation", Karl finds a radio and makes contact with a group of survivors heading towards the reef. He manages to direct a navy ship to rescue them. He has the option to leave Dinotopia by telling them his coordinates, but decides to stay on the island after Frank reasons with him.
Razor Reef appears to be some mysterious force of nature. It isn't just the storm, as it never deteriorates, and the Scott's plane seemed to almost power down on its own, meaning that the reef may disable electrical systems.
Although non-canon, in Dinotopia: Quest for the Ruby Sunstone, Albagon states how the sunstones create a barrier between Dinotopia and the outside world. This could suggest that the magic of the sunstones is what keeps Razor Reef going.