People and the press have referred to last year’s historic flood as a “thousand year” flood, as if an event of this size wouldn’t happen for another millennium. Not so, say John Shelton of the U.S. Geological Survey and state climatologist Hope Mizzell. Surprisingly, perhaps, each year the odds of a similar flood happening, though remote, are exactly the same. Mizzell says the “thousand year” designation, however, does have a use, as a criterion for designing certain structures which must be