This document is from the Ready program, "America's PrepareAthon!". "Hurricanes are massive storm systems that form over the water and move toward land. Threats from hurricanes include high winds, heavy rainfall, storm surge, coastal and inland flooding, rip currents, and tornadoes. These large storms are called typhoons in the North Pacific Ocean and cyclones in other parts of the world. The Saffir-Simpson Hurricane Wind Scale classifies hurricanes into five categories based on their wind speed, central pressure, and wind damage potential. With wind speeds of 111 miles per hour or more, Category 3, 4, and 5 hurricanes are major according to this scale. Category 1 and 2 hurricanes can also cause damage and injuries. The Saffir-Simpson scale is shown at the end of this document."
Federal Emergency Management Agency: http://www.fema.gov/