The Saffir-Simpson scale, used for decades, relies solely on wind speed to categorize hurricanes from 1 to 5. However, this method ignores the deadly dangers of storm surges and intense rainfall. These phenomena are responsible for the majority of deaths during these extreme weather events.
Experts emphasize that many human losses occur when the announced category doesn't reflect the real threat. Jennifer Collins, professor at the University of South Florida, explains that people often rely on this number to decide whether to evacuate or not. This can lead to tragic situations when risks are underestimated.
Hurricane Florence in 2018, classified only as category 1, nevertheless caused devastating floods that resulted in 55 deaths.
Credit: NASA/Goddard Space Flight Center
To address this problem, a team of researchers has developed the Tropical Cyclone Severity Scale (TCSS). This system integrates three parameters: wind speed, storm surge magnitude, and rainfall amounts. Each hazard receives a rating from 1 to 5, combined to obtain a more representative overall score.
A recent study tested this new scale with 4,000 people living on American coasts. Participants exposed to TCSS warnings better identified the main dangers and were more likely to evacuate.
The results, published in
Scientific Reports, show that TCSS allows for better hurricane preparedness. By providing a more complete picture of threats, this system helps populations take appropriate measures, such as protecting their homes or seeking shelter in time.
What is a storm surge?
A storm surge is an abnormal rise in sea level caused by strong winds and low atmospheric pressure during a hurricane. It can submerge coastal areas and cause destructive flooding. These giant waves are often the deadliest danger of hurricanes, even when winds are moderate. Their height depends on the storm's strength and coastal configuration, with varying impacts depending on the region.
Unlike tsunamis, storm surges are generated by weather conditions rather than earthquakes. Their prediction is difficult but important for alerting at-risk populations and organizing evacuations. Modern models use satellite and oceanographic data to estimate the magnitude of these phenomena. Integrating these forecasts into warning systems significantly improves public safety.
How does the Saffir-Simpson scale work?
The Saffir-Simpson scale classifies hurricanes into five categories based solely on maximum sustained wind speeds. It ranges from category 1 (winds of 74-95 mph or 119-153 km/h) to category 5 (winds exceeding 157 mph or 252 km/h). Developed in the 1970s, this scale aims to estimate potential damage to structures. However, it doesn't account for other critical factors like rainfall or tides, limiting its effectiveness.
Despite its shortcomings, it remains widely used by meteorological services for its simplicity. Critics point out that it can be misleading by underestimating non-wind-related risks. Alternatives like TCSS seek to address these deficiencies by integrating multiple parameters.