Head in the Clouds: Andrew

Today (August 24) marks the twentieth anniversary of Hurricane Andrew's landfall in south Florida. In total, the storm caused about $25 billion in damages and was directly responsible for 26 deaths. At landfall, Andrew was a classified as a category 5 hurricane on the Saffir-Simpson intensity scale, which means its maximum sustained winds, when averaged over one minute, were greater than 135kt (about 155mph) and the surface pressure in its eye was 922mb. This is roughly the air pressure found over 750m (over 2460ft) above mean sea level. It is also the third lowest recorded pressure of a hurricane at landfall on mainland U.S. since records began.

Collage of enhanced satellite images of Andrew (NOAA)

Strangely, Andrew was part of an unusually quiet Atlantic hurricane season. It was the first named storm of the year, yet it was born in mid-August. While this year's season got off to a very early start with tropical storm Alberto in May, the typical season should have its first named storm by mid-July. Even Andrew had a tough time at first, it took six days for it to reach hurricane strength and had a brief weakening as it passed over the Bahamas.
What makes this storm so important is that a whole lot of data was gathered from it, from the time it approached the Miami area, through its time over southern Florida, and during its second landfall in Louisiana. The Florida data is especially valuable, since the storm was one of just three or four hurricanes that made landfall on the U.S. mainland at category 5 strength since records begin. The one piece of data that is not available however, is radar data of the storm as it tracked across the Dade County; since those cat. 5 winds destroyed the National Weather Service's Miami radar!