A hurricane is a powerful, rotating storm system characterized by a low-pressure center, thunderstorms, and strong winds spiraling inward over warm ocean waters. These events are classified using the Saffir-Simpson Hurricane Wind Scale to communicate potential danger to the public and emergency management officials. This established system currently caps out at Category 5. Scientists are now debating whether the increasing intensity of modern storms necessitates the creation of a new, higher classification.
Understanding the Saffir-Simpson Scale
The Saffir-Simpson Hurricane Wind Scale classifies hurricanes based solely on the intensity of their maximum sustained wind speeds. This five-point index estimates potential property damage from wind once a tropical storm strengthens into a hurricane, which occurs when winds reach 74 miles per hour.
A Category 1 hurricane features sustained winds between 74 and 95 miles per hour, capable of producing minor damage, such as to roof shingles and shallowly rooted trees. Category 2 storms (96–110 mph) cause extensive damage to homes and result in near-total power loss lasting days to weeks.
Category 3 (111–129 mph) is the threshold for a “major hurricane,” capable of causing devastating structural damage to well-built framed homes. Category 4 (130–156 mph) causes catastrophic damage, often isolating residential areas due to fallen trees and power poles. The scale’s maximum, Category 5, is defined as any storm with sustained winds of 157 miles per hour or higher.
Defining Catastrophic Damage
The Saffir-Simpson scale ends at Category 5 based on the concept of damage saturation. Once a storm reaches the 157 miles per hour threshold, the resulting destruction is considered catastrophic, representing a functional maximum of wind damage. At this intensity, a high percentage of framed homes are destroyed, with total roof failure and wall collapse being common. The affected area can become uninhabitable for weeks or months.
For public safety officials, the practical difference between a wind speed of 160 mph and 200 mph is negligible for preparedness and response. Once the Category 5 benchmark is surpassed, structures are subjected to near-total failure regardless of slightly stronger winds. The Category 5 designation already triggers the most extreme warnings and evacuation orders, communicating the risk level that requires maximum protective action.
Scientific Discussion for a New Category
A growing number of scientists argue that a new category is needed due to the increasing intensity of tropical cyclones globally. Climate change contributes to higher sea surface temperatures, providing more energy for storms to intensify significantly beyond the Category 5 lower limit. This has led researchers to call the “open-ended” nature of Category 5 problematic for accurately communicating risk.
Recent research proposes a hypothetical Category 6 for hurricanes with sustained wind speeds of 192 miles per hour or greater. This threshold is based on analyzing the wind speed ranges of the lower categories and extrapolating a logical next step. Since 2013, five storms have reached or exceeded this proposed 192 mph benchmark.
Proponents argue that a Category 6 would raise public awareness about the increasing wind-hazard risk associated with the most extreme events. However, some meteorologists worry that adding a new category could cause alarm fatigue or diminish the perceived threat of a Category 5 storm. Furthermore, the Saffir-Simpson scale only accounts for wind, while water—from storm surge and rainfall—remains the deadliest element of a hurricane. The discussion aims to find the best way to communicate the heightened danger from these powerful storms without confusing the public or diverting attention from all associated hazards.