The disappointing truth is that most tidal waves (tsunamis) are only a few feet high and occur in the middle of the ocean where they go unnoticed. But this is not, of course, the answer your child is looking for. Images of the movie 2012 and destruction of biblical proportions are what is being pictured in their minds, and they want to know if there is any real hope of a wave covering most of the Empire State Building. Fortunately, there is. Or was.
On the night of July 9, 1958 an earthquake along the Fairweather Fault in the Alaska Panhandle generated a tidal wave 1720 feet high. Millions of trees were uprooted and swept away by the wave, which is the highest wave that has ever been known. The average two-story house is about 50 feet tall. This wave was the height of more than 30 houses stacked on top of one another. Grab your surfboard and head to Alaska.