Alabama Gulf Coast

Alabama's Gulf Coast stretches only about 50 kilometres from the Florida state line to Mobile Bay's mouth — one of the shortest saltwater coastlines of any US state — but it contains two distinct tidal environments. The outer coast, anchored by Gulf Shores and Orange Beach on the Pleasure Island barrier, faces the open Gulf of Mexico and experiences a diurnal tidal pattern: typically one high and one low per day, with a mean range of only 0.4 to 0.5 metres. This small range is characteristic of the northern Gulf, where the basin geometry and the low-frequency response of the Gulf's resonant modes produce predominantly diurnal tides instead of the semidiurnal pattern that dominates the Atlantic coast. Behind the barrier, Mobile Bay is a large, shallow estuary with a surface area of over 1,000 square kilometres. Tidal exchange with the Gulf occurs through Mobile Pass at the southern tip, but the bay's geometry and the large freshwater inflow from the Mobile-Tensaw river delta at its northern end mean that wind setup and river stage often dominate water-level fluctuations more than the astronomical tide. During sustained south winds, the bay's water level can rise half a metre above predicted tide; north winds push it down. The bay supports one of the most important commercial fisheries in the Gulf, particularly shrimp, blue crab, and oysters, all of which depend on the estuarine salinity gradient maintained by that tidal and freshwater interplay. NOAA CO-OPS maintains tide stations at Gulf Shores (Dauphin Island, station 8735180), Mobile State Docks (station 8737048), and Bayou La Batre. Predictions on this page come from Open-Meteo Marine; for wind-driven water-level events in Mobile Bay, the NOAA water-level forecasts and NWS storm surge guidance are the operational references.