tidal wave
n//ˈtaɪdəlweɪv//flodvåg, tidvattenvåg, tsunami, tidvattensvåg
A large and sudden rise and fall in the tide.
(proscribed) A large, sudden inundation of water from the storm surge, or waves of that surge; a sudden surge of river water.
(proscribed) A large, sudden, and disastrous wave of water caused by a tremendous disturbance in the ocean; a tsunami. (See Usage notes below.)