Magnitude is a measure of the strength of a hazard event. The magnitude of a hazard is usually determined using technical measures specific to the hazard. For example, the Enhanced Fujita Scale is used to measure the magnitude of tornadoes so that there is a common language, such as when someone refers to a tornado as EF-3. The magnitude of hurricanes is measured by the Saffir-Simpson Hurricane Wind Scale which provides consistency; thus, a category 3 hurricane is the same regardless of location. Earthquake magnitude is measured with the Richter Scale, and intensity is measured with the Modified Mercalli Intensity (MMI) Scale. All of these scales are damage severity measurements based upon analysis of previous catastrophic events.

Additional information about magnitude scales is available in the Toolkit.