It's been nearly 10 years since Tropical Storm Allison
devastated the Houston area with 40 inches of rain. The
floodwaters shut down hospitals, destroyed thousands of homes
and killed 23 people in Texas. The storm caused flooding the
first time it passed over the bayou city on June 4, 2001. But
the worst flooding came a few days later when it turned around
and targeted Houston again. Allison caused $5.5 billion in
damages and taught Houstonians that tropical storms can be even
more dangerous than hurricanes. It remains the deadliest and
costliest storm in U.S. history.