Researchers say Hurricane Katrina was a weaker storm than first thought when it slammed the Gulf Coast.
New data from the National Hurricane Center shows that Katrina was a Category Three storm and not a Category Four. It says top winds were about 125 miles per hour at landfall, and that New Orleans and Lake Pontchartrain were likely spared the storm's
New Orleans storm levees were believed to be able to protect the city from the flooding of a Category Three storm, but portions of the levee system were either topped or failed, leaving up to 80 percent of the city under water. An investigation into why the system failed is underway.
Category Three storms range from 111 miles per hour to 130, so Katrina was on the strong side of that ranking. Category Four storms run from 131 to 155 miles per hour.
Katrina's strongest winds and highest storm surge did ravage the Mississippi coast, wrecking the area's casino industry and flooding thousands of homes and businesses.
The report says measuring the surge's height was difficult because of many buildings were washed away, leaving few structures with high water marks. The best estimate was a 27 foot reading in Hancock, Mississippi.