Tropical Storm Katrina. Tropical Storm Katrina as observed by NASA's QuikSCAT satellite on Aug 25, 2005. The storm had 80 km/hour (50 mph) sustained winds and had not yet reached hurricane strength. The image depicts wind speed in colour and wind direction with small barbs. White barbs point areas of heavy rain. The highest wind speeds, in purple, surround the of the storm (NASA Media Archives). Buy this as a superb wall poster, a canvas print or a framed print.