When the tide comes in, it forms a tidal wave.The surface of oceans changes periodically in that it rises and falls (= the tides).

Link to present incidents:
No-one who heard it will ever forget the tidal wave of sound welling from the depths of the crowd that greeted the news that Mr Obama had won - it rippled back through the crowd that stretched far into the darkness of the night and seemed to hang and echo between the downtown skyscrapers.