Hurricane category 6 could be introduced under new storm severity scale

Summary

A new hurricane categorization system could help people better prepare for storms by incorporating risks from storm surges and rainfall into the categories, a study published this month reveals.Storm surges — elevated seawater levels near coasts — and rainfall cause almost 80% of hurricane deaths, yet they are not accounted for in the Saffir-Simpson Hurricane Wind Scale (SSHWS), which forecasters currently use to categorize a hurricane's severity and plays a key role in communicating hurricane risk to the public. Some experts have previously argued that the threat of storms is not always properly reflected in the SSHWS's 1 to 5 category ratings, which are based solely on wind speed."There have been too many instances of incredible loss of life and destruction because a low category number on the SSHWS [...] did not match the danger of the storm," Jennifer Collins, a professor in the School of Geosciences at the University of South Florida and co-author of the new study, said in a statement.The SSHWS estimates potential property damage from sustained wind, ranging from "some damage" in a Category 1 hurricane to "catastrophic damage" in a Category 4 or 5 storm. But property damage isn't the only potentially deadly effect of a hurricane. A low-category hurricane may still cause a tremendous tidal surge and unleash torrential rain, triggering devastating floods and other hazards.One example is 2005's Hurricane Katrina, which was listed as a Category 3 based on wind speeds. But storm surge and rainfall were responsible for most of the 1,800 deaths caused by Katrina and contributed hugely to the $125 billion in damage, according to the new study.Another example is Hurricane Florence, which made landfall in South Carolina in 2018 as a Category 1. The low danger rating did not alert communities to the catastrophic flooding that killed 55 people across the southeastern U.S., the researchers said.Related: Birth of a hurricane: What meteorologists look for as they hunt for ear...