By the way, it's time to revive the old term "tidal wave" as a complement to the Japanese term "tsunami." During my childhood, most Americans used the term tidal wave, but scientists and science journalists waged a war against it on the simpleminded grounds that tidal waves weren't caused by tides. So, by switching to tsunami, we lost the metaphorically powerful term tidal wave, which does a much better job of hinting at the peculiar horror of this phenomenon compared to normal waves. It's not the height of the front of the tidal wave that is so destructive — lots of people have surfed waves as tall. It's that, unlike regular beach waves, the water level doesn't go down after the front passes. It's as if the tide has suddenly risen, but with a great velocity to the water rolling in. In cross-section, a tidal wave isn't an inverted V, it's like an inverted L that just keeps going.