Why no ways?
Reef areas exposed at low tide?
But many coral reefs and rocky reefs have small areas sections that are exposed at low tide, and the common definition for "reef" does not require full submersion at low tide:
https://en.oxforddictionaries.com/definition/reef - "1 A ridge of jagged rock, coral, or sand just above or below the surface of the sea."
https://dictionary.cambridge.org/dictionary/english/reef - "1.1 a line of rocks or sand just above or just below the surface of the sea, often dangerous to ships" --Jeisenbe (talk) 12:35, 3 June 2019 (UTC)