The 2004 hurricane season started on July 31 with Hurricane Alex and continued all the way through to December 2 with Tropical Storm Otto. The season featured 15 tropical storms, 9 of which became hurricanes, and 6 of those were classified as major hurricanes. This over-active hurricane season tallied up a bill of $42 billion in damages, which at the time was record high. Florida took the brunt of the damage with 4 major hurricanes making landfall in the state. Two of the hurricanes, Frances and Jeanne, landed in almost the same location on the east coast of Florida only 3 weeks apart. It is estimated that one in every five homes in Florida was damaged in the 2004 hurricane season.
This data set was created using infrared satellites, which measure emitted heat. Where there are clouds, the satellites measure the heat emitted by the cloud rather than the ground below it. Because clouds are so much colder than the ground, they are easy to detect on IR satellite images. Areas that show up in the bright colors are extremely cold and the gray shades are areas that are warmer. The higher the cloud, the colder the cloud top will be and so it shows up vividly on the IR satellite image. Hurricanes and tropical storms are well developed weather systems and therefore have high clouds that are easy to detect in the IR satellite images.