On land, the passage of a severe storm might be marked by fallen trees or swollen streams. In the ocean, a hurricane leaves a swath of cold water in its path. That trail of cold water marks the passage of Hurricane Bertha through the North Atlantic Ocean in this sea surface temperature image, taken by the Advanced Microwave Scanning Radiometer for EOS (AMSR-E) on NASA’s Aqua satellite on July 7, 2008. Water that is warm enough to fuel a hurricane—about 28 degrees Celsius (82 degrees Fahrenheit)—is yellow and orange, while cooler water is blue and white.
