Trillian Tide

In the fantasy book, "The Trinity Throne", a Trillan Tide is a low tide that occurs within the Tjor Sea once every 6 to 9 years. It is signaled by the appearance of the spiritually important trill bird from the south. When the migratory bird appears, a low tide will begin up until the next new moon. This tide is important because it is the only brief time when a safe path to the island fortress of Fjorgallahar is paved. The Trillian Tide lasts only briefly, often just days, until wild weather and high seas make Fjorgallahar inaccessible again. This time marks when a race to crown a new Trinity King/Queen is to begin.

Other times are noted as "high tide", and it is not safe to sail, swim, or fly near Fjorgallahar at this time.