Historical Floods And Flash Floods
Flooding poses tremendous danger to both people and property. Since 1900, floods have taken more than 10,000 lives in the United States alone. Because it is often difficult to judge the depth of the water or the speed of the current, flood waters can be deceptive.
The Big Thompson Canyon (Colorado) Flood, which killed 139 people in 1976, proved a tragic illustration of a sobering statistic - 95% of those killed in the flash flood tried to outrun the waters along their path rather than climbing rocks or going uphill to higher grounds.
In recent years, about two-thirds of the flood fatalities have been in vehicles. Only a foot of fast-flowing water can push a vehicle off the road and sweep it downstream. About two feet of water will float a vehicle.
Beyond the risk of fatalities, floods devastate homes, towns, and even entire regions. The great Mississippi River Flood of 1993 covered an area 500 miles long and 200 miles wide. More than 50,000 homes were damaged, and 12,000 miles of farmland were washed out.
June 1972 was a traumatic month. In the Black Hills of South Dakota, a series of thunderstorms caused heavy rains along the eastern slopes, resulting in flash flooding along Rapid Creek, which flows through Rapid City, South Dakota. The flooding caused more than $100 million in damage and at least 237 people died.
During that same month in the east, the remnants of Hurricane Agnes caused torrential rains across the mid-Atlantic states, especially from Virginia through New York. In the subsequent flooding and flash floods, 118 people perished and entire communities were inundated.
On the West Coast, it is often winter storms that bring flooding. For example, in February 1978, over 20 lives were lost in the Los Angeles area during the worst rainstorms ever seen in Southern California. Successive rain and mud slides during March brought damage totaling more than $80 million and increased the death toll to nearly 40 people.
Torrential rains from the remnants of Tropical Storm Allison inundated parts of the Houston metro area in June 2001. Up to 36 inches of rain fell on the east side of Houston, and 41 perished in the flood.
Hurricane Katrina caused the deadliest recent flood on August 29, 2005. Strong winds forced waters of Lake Ponchartrain into adjacent canals, some of which failed. Water flowed through the breaks, inundating much of the city to depths of up to 15 feet. About 1,800 were killed by the hurricane, with more than 1,400 of those in Louisiana flooding.
Other historical flash floods include the Johnstown Flood of 1889 and the Shadyside, Ohio Flood of 1990.
[Some data courtesy of The Thunderstorm in Human Affairs, Edwin Kessler, Editor.]