The U.S. Census Bureau estimates that population growth in counties near to those affected by Katrina doubled when tens of thousands of people were displaced by the hurricane.
The population estimates for July 1, 2006, mark the first measure of the hurricane's impact on the populations of coastal communities in the 10 months between the August 2005 storm and the date of the estimate, the Census Bureau said in a release.
The population changes were pronounced in Orleans Parish, which lost half of its population from July 2005 to July 2006, and nearby St. Bernard Parish, which lost three-quarters of its 65,000 residents.
Gregory Rigamer, president of New Orleans planning firm GCR & Associates, told USA Today the population changes are "significant but manageable" across much of the coast. He said New Orleans and other communities heavily damaged by Katrina still face "a colossal challenge and one that puts those communities at risk."