The maximum height a tsunami reaches above sea level on land is called run-up.
Run-up measures how far seawater climbs vertically above a stated sea-level reference as it inundates the shore. It is not the same as wave height, which describes the vertical distance between a wave’s crest and trough, usually at sea or near a measuring station.
Tsunami run-up depends heavily on coastal shape, slope, reefs, bays, vegetation, buildings, and the tide when the wave arrives. A tsunami may be low in the deep ocean yet rise dramatically near shore as the seafloor becomes shallow and the water is forced landward.
The term is also associated with the inland limit of flooding, although scientists distinguish run-up elevation from inundation distance. Extreme local events can produce enormous run-up: the 1958 Lituya Bay megatsunami in Alaska reached about 524 metres above sea level.