A Defense Meteorological Satellite Program satellite microwave image of Hurricane Katrina showing rainfall rates as the storm made landfall on the Gulf Coast of the United States Aug. 29, 2005. The DMSP F-15 satellite provides microwave imagery used to determine realtime rainfall rates during tropical storms. The yellow areas have rates of 1 inch per hour. The blue areas are rates of 1.5 to 2.5 inches per hour. Image courtesy of the Air Force Weather Agency.