Hurricane Anatomy

Part A: The Saffir-Simpson Scale

Saffir-Simpson Hurricane Scale

One piece of information you'll hear about repeatedly while studying hurricanes is the Saffir-Simpson Scale of cyclone intensity. The scale is based on measurements of sustained wind speed; it categorizes hurricanes from 1 (lowest intensity) to 5 (most intense). The technical definition of a hurricane is winds of 74 miles per hour or greater, sustained for 1 minute. You can see the major delineations of the scale in the chart on the right. You can also read more about what goes into ranking storms at the following links:

Checking In Questions

You may well see wind speed data presented in km/h (kilometers per hour) so you should be able to convert between mph, knots, and km/h if you have to.

  • If a storm has a wind speed of 135 km/h and 1 km/h = 0.621 mph = 0.540 knots, what is the wind speed in mph and knots?
  • Where would this storm rate on the Saffir-Simpson Scale?

Optional Extensions

What is a Typhoon? & Saffir-Simpson Scale