MODIS acquired the top image on May 18, 2011, and the bottom image on May 4, 2011. Both images use a combination of visible and infrared light to increase contrast between water and land. Water ranges in color from gray-blue to navy. (Lake Pontchartrain appears silvery blue on May 18 due largely to the angle of sunlight.) Vegetation is green. Bare ground is brown. Clouds are pale blue-green and cast shadows.
Both images show flooded conditions along the Mississippi River. A significant difference between the images, however, is the water visible in the Morganza Floodway on May 18. The Army Corps of Engineers reported that the discharge in the floodway was 108,000 cubic feet per second on May 18, the floodway's fifth day of operation in 2011.