Most Destructive Storm Ever?

Hurricane Katrina has become the most destructive such storm ever to strike the United States, the National Oceanic and Atmospheric Administration said Thursday.

Katrina's sustained winds reached 175 mph and its minimum central pressure dropped as low as 902 millibars — the fourth lowest on record for an Atlantic hurricane, NOAA's National Climatic Data Center (search) reported.

The storm weakened slightly before it reached landfall and had less powerful winds than Hurricane Camille (search), which devastated coastal Mississippi in August, 1969.

But the size of Katrina, with hurricane force winds extending 120 miles from its center, was much larger and the destruction more widespread than Camille.

The central pressure in a hurricane is a good indicator of the strength of the winds of the storm. The strongest observed hurricane in the Atlantic basin was Gilbert in 1988 with a pressure of 888 millibars in the northwest Caribbean. Normal average sea level air pressure is 1,016 millibars.

Katrina was the 11th named storm of a busy season, first striking southern Florida on August 25 as a Category 1 storm. It quickly re-intensified once it moved west into the warm Gulf waters, which were 2 to 3 degrees Fahrenheit above normal. It's the evaporation from warm ocean waters that provides energy for hurricanes.

Estimates so far are that Katrina cost the Gulf Coast area at least $125 billion in economic damage and could cost the insurance industry up to $60 billion in claims, a leading risk assessment firm said in updated estimates released Friday.

That's significantly higher than the previous record-setting storm, Hurricane Andrew in 1992, which caused nearly $21 billion in insured losses in today's dollars.