What’s in a number? If you’re in the path of a hurricane, the traditional number assigned to it—from the comparatively weak Category 1 storm to the most severe Category 5—might very well determine whether you feel you need to get out of the way. And that, in part, is why some forecasters are trying to change the way we talk about hurricanes.  

The Saffir-Simpson scale, with whose categories most of us are familiar, is a measure of wind speed; a Category 1 hurricane, for example, has winds up to 95 mph that usually cause fairly minor damage, while a Category 5’s 157-mph-and-higher winds can level buildings. But this scale has little to say about water, the other, and potentially more dangerous, component of a hurricane.  

An article in the September 2017 issue of Stormwater reported on a new warning system just then taking effect, which issues watches and warnings for storm surges as well as for wind. By far, most hurricane-related deaths are caused by water—flooding, high surf, and storm surge—rather than by wind. Many of the people interviewed for that article wanted to impress upon people the dangers of water.  

Today, however, even with those changes, meteorologists and public officials are still concerned about the way we describe impending storms. Some say continuing to use the Saffir-Simpson categories is not an effective way to convey the danger. A hurricane might be downgraded from, say, a Category 4 to a Category 1 based solely on lessening wind speed, but the amount of rain and flooding it brings might be just the same.  

As this article reports, last September that exact scenario played out with Hurricane Florence; it went from a Category 4 to a Category 1 storm. As it was downgraded, many in its path assumed the threat was no longer serious. But 17 of the 23 people whose deaths were attributed directly to the storm died as a result of freshwater drowning. Months after Florence, AccuWeather introduced what it calls the Real Impact Category to characterize storms based on all associated threats: wind, rain, storm surge, and economic loss. According to its parameters, Florence would have remained a Category 4 storm when it hit land.  

Other experts, such as Rick Knabb, former director of the National Hurricane Center and now tropical program manager for The Weather Channel, believe the public would be better served if commentators and public officials avoided numerical categories altogether and instead just described the potential damage from things like rain and storm surge.