The National Hurricane Center has downgraded Hurricane Camille’s strength at its catastrophic landfall in 1969.

The Category 5 hurricane came ashore along Mississippi’s coast. The storm was blamed for 256 deaths in the U.S. and $1.4 billion in damage at the time.

Researchers from the hurricane center and Florida International University re-analyzed original observations from ships, weather stations, coastal radars, reconnaissance planes and satellite imagery. They determined that Camille’s wind strength peaked at 175 mph, not the 190 mph previously recorded.

Category 5 hurricanes have maximum sustained winds of 157 mph or higher.

Camille is the second-strongest hurricane to strike the U.S. mainland since 1900. The Florida Keys Labor Day Hurricane in 1935 is first with 185 mph winds, and Hurricane Andrew in 1992 is third with 165 mph winds.