>Via NASA's Terra Satellite:

tennessee floods1.jpg
tennessee floods2.jpg

Record rains have set off extensive flooding in Tennessee, Mississippi, and Kentucky, killing at least 27 people. NASA used a spectroradiometer to gather the two images above, combining infrared and visible light to increase the contrast between water and land.

The lower image was gathered two days before the storm, and the upper one three days after it began. You can track the flooding by comparing the blue and black parts of the images, which show swollen rivers and streams.