This pair of images from the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASAs Terra satellite use a combination of visible and infrared light to make floodwaters obvious. Water is blue or nearly black, vegetation is bright green, bare ground is tan, and clouds are white or light blue.

AP Photo/NASA

On the left: On April 15 (before the storm), rivers and lakes are sharply defined against a backdrop of vegetation and fallow agricultural land. The Irrawaddy River flows south through the left-hand side of the image. The wetlands near the shore are a deep blue green.

On the right: Cyclone Nargis came ashore across the Mouths of the Irrawaddy and followed the coastline northeast. The entire coastal plain is flooded in the May 5 image.