Coastal flood A coastal flood occurs when normally dry, low-lying land is flooded by high sea levels.
Datum A tidal datum is a reference elevation of sea level, defined in terms of a certain phase of a tide.
Mean sea level Mean sea level is the average height of the sea over longer periods of time (usually a month or year), with the shorter-term variations of tides and storm averaged out.
Neap tides Tides of small range which occur approximately twice a month, when the moon and sun are out of phase.
Return Period A return period is the average length of time in years between events such as the flooding of a particular level.
Sea level Sea level is the vertical change in the height of the sea surface which occurs over all time and space scales from many different mechanisms.
Skew Surge A skew surge is the time independent difference between the maximum observed water level and the maximum predicted tide.
Spring tides Tides of large range which occur approximately twice a month, when the moon and sun are in phase.
Storm surge A storm surge is large change in sea level generated by low atmospheric pressure and strong winds associated with an extreme meteorological event.
Tidal range Tidal range is the vertical difference in height between consecutive high and low waters over a tidal cycle.
Tide gauge A tide gauges is an instrument that measures the vertical movement of the sea surface.
Tides Tides are the regular and predictable rise and fall of the sea caused by the gravitational attraction and rotation of the earth, moon and sun system.
Water level Water level is the height of the sea surface above some reference level or benchmark, often called a tidal datum.
Waves Local or remote storms produce large wind or swell waves, which can overtop coastal defences/beaches and cause flooding and erosion.
