Cyclone intensity is measured by either a one- or ten-minute mean wind speed, depending on who is doing the measuring. Most use the ten-minute mean, though our Dept. of Defense uses the one-minute mean. There are five levels of intensity. In increasing order of intensity these are:
The second link below is especially useful, if you need more information.
A tropical cyclone is another name for a hurricane, typhoon, and cyclone. The intensity is described on a scale known as the Saffir-Simpson scale. The scale was devised in 1969 by Herbert Saffir and Dr. Bob Simpson, former director of the National Hurricane Center. The wind speed, based on 1-minute intervals, is used rather than storm surge potential because of differences in the shape of the continental slope in an area.
The rating are a scale from 1 to 5. Category 5 hurricanes are the most intense and damaging.