When the Army Corps of Engineers promises to protect southeast Louisiana from flooding triggered by a “100-year hurricane,” the all-too-common assumption is a storm that will occur only once a century.
But that misunderstanding can contribute to a world of bad decisions, from homeowners feeling secure enough to drop flood insurance to members of Congress refusing to finance a higher level of protection.
In reality, “100-year hurricane” is merely shorthand — poor shorthand, in the view of a growing number of community activists, scientists and government officials — for a storm that has a 1 in 100 chance of occurring in any given year. Such a storm could hit every year, or not at all for a century.
“The phrase ‘100-year-flood’ doesn’t communicate to the public or to policymakers the real risk of flooding. They think it means a flood that occurs once every 100 years, when in fact, there’s something like a 60 percent chance of experiencing it in your lifetime.”
The Southeast Louisiana Flood Protection Authority-East has also added its voice to a chorus challenging the federal government to devise a more easily understandable explanation of risk. The authority’s plea followed a similar one from the state’s Coastal Protection and Restoration Agency.