MIAMI, Aug. 21 (UPI) -- Hurricane Andrew was elevated Wednesday from a Category 4 hurricane on the Saffir-Simpson Hurricane Scale to a Category 5 with 165-mph winds, 10 years after it savaged south Miami-Dade County.
Research in the last 10 years has shown that the storm reached Category 5 strength shortly before it roared ashore. Actually, researchers said it was 9 mph more than the Category 5 minimum with 165-mph maximum sustained winds.
"There is always some uncertainty in determining the maximum winds in a hurricane, and Andrew is no exception," said Max Mayfield, director of the National Hurricane Center in Miami.
"Our previous estimate was 145 mph, based on the science available in 1992. With advanced research techniques and technology, we now estimate the winds were stronger," Mayfield said.
The change was made by the Best Track Committee of the National Oceanographic and Atmospheric Administration and the hurricane center. Herbert Saffir, a structural engineer who co-designed the scale with former hurricane center director Robert Simpson, reviewed the results.
The move makes Andrew only the third Category 5 on record to strike the continental United States. The others were the "1935 Florida Keys Hurricane" and Hurricane Camile that hit the Mississippi Gulf Coast in 1969.
Andrew struck the Homestead, Fla., area Aug. 24, 1992, and tore the area apart, destroying 25,000 homes and severely damaging 100,000. It was the most costly natural disaster in the nation's history at $26.5 billion.
More than 60 deaths have been attributed to the storm either directly or indirectly in the aftermath. Fifteen people died in Florida during the three hours Andrew spent in south Florida.
The change in category was largely based on research involving Global Positioning System dropwindsondes, which went into use in 1997.
They are measuring devices dropped from hurricane reconnaissance aircraft into the eye wall -- the windiest part of the hurricane. The sonde system measures temperature, barometric pressure, water vapor and wind data every 15 feet on its way down.
The analysis of dropwindsonde data indicated that on average the maximum sustained surface-wind speed was about 90 percent of the wind speed measured at the 10,000 level flown by an aircraft into Andrew as it approached south Florida.
In 1992, Andrew's wind speed was estimated at 75 percent to 80 percent of the aircraft observations.
The research findings resulted in an increase in the estimated wind speeds of Hurricane Andrew from 145 mph to 165 mph.