The new hurricane classification system could help people prepare for storms by incorporating risks from storms and rainfall into categories, a study published this month reveals.
Storm surge – rising seawater levels near the coast – and rainfall causes almost 80% of hurricane deaths, but not explained by the Safir Simpson Hurricane Wind Scale (SSHWS). Some experts argue that storm threats are not always properly reflected in ratings of 1-5 categories of SSHWS, which are based solely on wind speeds.
“There have been too many cases of surprising loss of life and destruction due to the low number of SSHWS categories. […] Jennifer Collins, a professor in the Department of Earth Sciences at the University of South Florida and co-author of the new study, did not match the dangers of the storm.
You might like it
SSHWS estimates potential property damage from persistent winds, ranging from “some degree of damage” in Category 1 hurricanes to “catastrophic damage” in Category 4 or 5 storms. However, the potentially fatal impact of a hurricane is not the only property damage. Low-category hurricanes still cause a tremendous surge in tides, unleashing heavy rain, causing catastrophic flooding and other dangers.
One example is Hurricane Katrina from 2005, listed as Category 3 based on wind speed. However, new research shows that storm surges and rainfall are the most of the 1,800 deaths caused by Katrina, and have contributed significantly to the $125 billion damage.
Another example is Hurricane Florence, which landed in South Carolina as Category 1 in 2018. The low-risk rating did not warn the community about the devastating floods that killed 55 people in the southeastern United States, researchers said.
Related: The Birth of a Hurricane: What Meteorologists are Looking for when they are looking for early signs of tropical cyclone formation
“Frequently, people use the storm category to decide whether to evacuate,” Collins said. “It’s very dangerous because if they hear it’s a tropical storm or category 1, the alarm bell doesn’t go away and they think there’s no source of concern.”
To address the shortcomings of SSHWS, Collins and his colleagues developed an alternative hurricane warning system in 2021. The system, known as the Tropical Cyclone Scale (TCSS), comes in six categories, taking into account wind speed, storm surge and rainfall.
TCSS assigns a score of 1-5 to each of the three hazards, depending on the predicted severity of a particular hurricane. These scores are then combined into the final score and established using three rules in different scenarios.
First, the final score is not the lowest of the three individual hazard scores. Second, if the score for two individual hazards is 3 or higher, the final score increases by one. Hurricanes therefore fall into category 4 if the score for storm surge is 2, but both wind and rainfall are 3. The third rule is if two hazards score 5, or if two hazards score 4, and the final score of 6 is 6.
“The higher categories are important,” Collins said. “Many people are based on decisions to evacuate to that number, not just the details of the danger.”
“More realistic” system
Researchers have been working on TCSS for several years, but new research has called for confirmation of its effectiveness in warning the public about the risk of hurricanes. To test the warning system, Collins and her colleagues sent 4,000 participants living along the Gulf and East Coast with predictions of 10 fictional hurricanes affecting the community.
Half of the participants were warned in SSHWS format, while the other half were warned using the TCSS system. I then completed an online quiz on how to respond in different scenarios. The team’s findings were published in the journal Scientific Reports on August 19th.
Participants sent with TCSS predictions were more likely to correctly identify the main risks from hurricanes, and were significantly more likely to evacuate due to non-wind hazards than those sent with SSHWS predictions.
Correct identification of the main hazard was intended for participants to take relevant precautions, such as protecting their homes from flooding with sandbags and building window protection against wind. Meanwhile, participants with incomplete information about the storm were more likely to incorrectly calculate the risk or not take any measures at all.
The results suggest that leaving SSHWS will improve public understanding of hurricane risks and lead to more informed decisions ahead of the storm, Collins said.
“I’m pretty optimistic that it’s the time,” she said. “We know that many people now make decisions based on category messaging, so we need to make sure that hurricane severity is communicating with a more realistic scale.”
Source link
