AdvertisementWhy Typhoon Haiyan Caused So Much DamageNovember 11, 2013Richard HarrisfacebookEmailThis map from the NOAA Environmental Visualization Laboratory shows the amount of heat energy available to Typhoon Haiyan between Oct. 28 and Nov. 3. Darker purple indicates more available energy. Typhoons gain their strength by drawing heat out of the ocean. The path of the storm is marked with the black line in the center of the image. (NOAA Environmental Visualization Laboratory)