South Pacific Ocean Tropical Cyclone Intensity Scale - Atlantic and East Pacific

Atlantic and East Pacific

The Saffir-Simpson Hurricane Scale is the classification system used for tropical cyclones in the Atlantic Ocean and in the Pacific Ocean east of the anti-meridian. The Saffir-Simpson Scale is based on 1-minute maximum sustained wind speeds. In these oceanic basins, tropical cyclones with maximum sustained winds below 34 kn (39 mph; 63 km/h) are labelled as tropical depressions by either the National Hurricane Center (if it is in the North Atlantic or North-east Pacific Basin) or the Central Pacific Hurricane Center (if located in the North Central Pacific Ocean). Should a tropical depression reach 35 kn (40 mph; 65 km/h), it will receive a name and will be classified as a tropical storm. If the tropical storm continues to intensify and reaches maximum sustained winds of 64 kn (74 mph; 119 km/h) then the tropical storm will be designated as a hurricane.

The Saffir-Simpson scale counts with five different classifications for the intensity of a hurricane, with a Category 1 storm having the lowest maximum winds, whilst a Category 5 hurricane having the highest. Storms that meet the 64-knot threshold, but do not possess maximum sustained winds in excess of 83 kn (96 mph; 154 km/h) are classified as Category 1 hurricanes. A Category 1 storm will be upgraded to a Category 2 hurricane if its maximum sustained winds reach 83 knots. Tropical cyclones that possess wind speeds of at least 96 kn (110 mph; 178 km/h) are classified as Category 3 hurricanes. Category 3 also marks the point at which the NHC and CPHC classify strong storms as major hurricanes. If a hurricane's maximum sustained winds reach 114 kn (131 mph; 211 km/h), it will be ranked as a Category 4 hurricane. Storms with winds that surpass 136 kn (157 mph; 252 km/h) are of Category 5 intensity. The SSHS was originally created using both wind speed and storm surge, but since the relationship between wind speed and storm surge is not necessarily definite, the scale was changed to the Saffir-Simpson Hurricane Wind Scale (SSHWS), based entirely on wind speed.

Although increasing echelons of the scale correspond to stronger winds, the rankings are not absolute in terms of effects. Lower-category storms can inflict greater damage than higher-category storms, depending on factors such as local terrain, population density and total rainfall. For instance, a Category 2 that strikes a major urban area will likely do more damage than a large Category 5 hurricane that strikes a mostly rural region. In fact, tropical systems of less than hurricane strength can produce significant damage and human casualties, especially from flooding and landslides.

Historically, the term great hurricane was used to describe storms that possessed winds of at least 110 kt (200 km/h, 125 mph), large radii (over 160 km / 100 mi) and that caused large amounts of destruction. This term fell into disuse after the introduction of the Saffir-Simpson scale in the early 1970s.