Measuring hurricanes and tornadoes

Today marks the beginning of the 2017 Atlantic hurricane season, which runs through the end of November. As you may be aware, we measure hurricane intensity by measuring the wind speed. We categorize hurricanes into one of five levels on the Saffir-Simpson scale. In use since 1971, the scale is widely known, but does it serve the public well?

The United States has not seen a landfall from a “major” (category 3 or above) hurricane since Hurricane Wilma in 2005. But that doesn’t tell the whole story. The original Saffir-Simpson scale included effects from storm surge and flooding. However, the Saffir-Simpson Hurricane Wind Scale in use today excludes those; it is solely a measure of wind speed. So even though the U.S. has avoided major hurricanes, it has not avoided major damage. Consider that two of the three costliest hurricanes in U.S. history were not major hurricanes. Sandy wasn’t even technically a hurricane.

More recently, Hurricane Matthew caused a great deal of devastation in the Carolinas and Virginia. Matthew could have caused massive damage along the Florida Atlantic coast, but remained just far enough out to sea. And the damage further north was primarily due to inland flooding, not the near-shore wind and surge. By the time Matthew reached the Carolinas, it was “just” a Category 1 storm. As a result, many in the public did not recognize the serious threat it posed.

The National Hurricane Center in particular, and the weather industry in general, are working to improve hazard communication. The public, after all, doesn’t really care about the wind speed per se, but the effects of that wind (and rain). Last fall, several meterologists on discussed this on Twitter:

The discussion turned to the idea of real-time rating of tornadoes. NOAA researchers found that weather radar velocity data can be used to estimate the ultimate Enhanced Fujita Scale rating of a tornado. While not operational yet, it will be a big benefit to the public if it is further developed.

The ideal situation would combine the impact focus of the EF scale with the real-time rating used for hurricanes. Hurricanes are much easier to evaluate in real time for a variety of reasons, so they have a head start. Now if we can just start measuring hurricanes correctly.

2 thoughts on “Measuring hurricanes and tornadoes

  1. Well, Tornadoes are rated after the damage has been done.

    Predicting damage is a risky thing. Bringing storm surge back into the mix might help, “Hurrican Derrick will have Cat 3 winds but Category 5 storm surge (or what…10 feet? just making stuff up here). Having essentially a 10 foot high wall of water will definitely help those idiots leave their homes on stilts that will still be underwater with some surge.

    Just spit balling over here and remember I have no specific meteorological knowledge or training. Just a rando on the internets toying with your ideas.

  2. @gizmomathboy, it’s true that predicting damage is tough, but it’s apparently possible (based on the linked study, which was a surprise to me, too). My main concern with assigning different values to wind/surge/flood threats is the possibility of confusion. I don’t know if it’s possible, but I’d like a single “how fucked am I?” scale. “Here’s the latest update for Hurricane Derrick. Coastal areas: kinda fucked. Inland areas: Supafucked.”

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