Hurricanes can be absolutely devastating, and over just the past several decades they have caused thousands of people to lose their life, and billions of dollars in damage. Currently, when a major storm is detected in the ocean, it is monitored closely by meteorologists, and if it meets the necessary criteria, it is assigned a category level based on its wind speed.

Experts use a classification system that is based on the Saffir-Simpson Hurricane Wind Scale (SSHWS). A hurricane is put into one of the following categories:

• Category 1 – Sustained Winds of 74-95 miles per hour (119-153 km/h)
• Category 2 – Sustained Winds of 96-110MPH (154-177 km/h)
• Category 3 – Sustained Winds of 111-129MPH (178-208 km/h)
• Category 4 – Sustained Winds of 130-156MPH (209-251 km/h)
• Category 5 – Sustained Winds of 157MPH (252km) or Higher

This system has been in place for a long time, and while it does give a general idea of just how powerful a storm is, it does not necessarily give details as to how dangerous it may be. This is because while high winds can certainly be dangerous, they are not the only risk factor in a hurricane. In fact, according to a 2014 study, just 8% of hurricane deaths are caused by wind, compared to 49% from storm surges, and 27% from rainfall.

With that in mind, researchers have developed a new hurricane rating system that they would like to see adopted. They published the paper on this new system in Scientific Reports, giving details not only of how the system would work, but why it is a better option. Professor Jennifer Collins is a hurricane researcher at the University of South Florida’s School of Geosciences, and the co-author of the study. In a statement, she explained:

“Frequently, people use the storm’s category to decide whether to evacuate. That’s incredibly dangerous because if they hear it’s only a tropical storm or Category 1, too often no alarm bells go off, and they see no cause for concern.”

One of the prime examples oof this is with the devastating Hurricane Katrina, which occurred in 2005. While it was only listed as a category 3 storm, it ended up taking the lives of 1800 people and costing $125 billion in damages, making it the most expensive storm ever. The bulk of both the deaths and the damage was from the devastating storm surge. Collins said:

“There have been too many instances of incredible loss of life and destruction because a low category number on the SSHWS, or even if it’s listed as a tropical storm, did not match the danger of the storm. Based on our research, we now know that people are more likely to evacuate if they understand the dangers from rainfall and storm surge in addition to wind.”

So, the new system that is proposed takes those things into account. Dubbed the Tropical Cyclone Severity Scale (TCSS), this new system would have meteorologists analyze a storm and identify its predicted severity in each of the categories: wind speed, rainfall, and storm surge.

Each category would be given a ranking between 1 and 5. When calculating the storm’s severity as a whole, the category scale goes from 1-6, which allows the experts to account for the added risk of situations where two or more of the categories are high. Specifically, the system works like this:

• The storms overall category level must be at least as high as the highest individual rating. For example, if a hurricane is ranked as a category 1 for rainfall, a category 3 for storm surge, and a category 2 for wind speed, the overall category would be a 3.
• When two or more of the categories are at a 3 or higher, then the final rating for the storm gets bumped up by one. For example, if a storm is rated at a 3 for both storm surge and wind speed, but a 1 for rainfall, it would get an overall severity rating of a 4.
• In the event that one category is a five and another is at least 3 or above, that would push the total storm to a Category 6, which is a new ranking for this system.

The team also studied whether this new system would help people to make better decisions when it comes to evacuating before a storm. After surveying 4000 residents along the Gulf and East coast, they found that people were indeed more likely to evacuate based off of information from the TCCS than they were with the SSHWS. In addition, they would be able to better prepare because they knew where the highest dangers were coming from. Collins talked about the potential for this new system to get adopted:

“Change is hard for any institution that’s been doing the same thing for years. But I’m fairly optimistic that now is the time. We now know many people make decisions based on the category messaging, so we need to ensure that we are communicating with a scale that is more realistic of the severity of the hurricane, considering other hazards which commonly occur, particularly from storm surge and rainfall flooding, which is considered in our scale.”

Let’s hope that this system can be adopted and lives can be saved.

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