Tidal Beaches

Beaches transformed twice a day by tidal range large enough to change what the place is: sea retreating a kilometre or more, sand flats appearing, and access windows that must be planned around. Range is the criterion, and the ranges here run to fourteen and sixteen metres. That produces beaches which are two different places six hours apart, walking routes that are legal only with a guide, mudflats that trap people, and access windows published as timetables. Every record in this world should be planned around a tide table rather than a clock. Several also carry hazards specific to this world: quicksand, channels that fill from behind, and mud that people become stuck in and have to be rescued from. Guided crossings exist on two of them and are the only lawful way to make the walk.