Anthony W. Lyza, Harold E. Brooks, and Makenzie J. Krocak have an early-access paper in the Bulletin of the American Meteorological Society wondering where the EF5s have gone. This paper is an interesting look at the extended “drought” in the strongest category of tornadoes. The title of my post is not questioning the value of their work, but the paper does make me wonder about the value of tornado ratings for the general public.
Ratings for research and forecasting
There’s certainly value for scientific research and forecasting. Because ratings are assigned based on damage, which is what people ultimately care about, there are benefits in being able to use large data sets to find patterns. “Which environments tend to produce more destructive tornadoes?” is an important question to know the answer to. The more warning we can give (at least to some extent) of the possibility of strong tornadoes, the more time people have to take appropriate precautions.
Of course, the EF rating system has flaws. Damage assessment, while greatly improved over the years, still involves subjective decisions. In addition, binning a spectrum always results in some funkiness (that’s the scientific term). The difference between 165 and 166 mph wouldn’t meaningfully change the damage caused by a tornado, but — assuming we could accurately measure tornadoes in order to rate them — would be the difference between and EF3 and EF4 rating. And there’s the question of whether or not six ratings (and the location of the boundaries) is the “best” approach. To wit: there are a variety of different categorizations of the ratings. Are any of them better suited?
Ratings for the public
But even with the value for science, do tornado ratings provide value to the public? As I wrote eight (!!) years ago, “even though the U.S. has avoided major hurricanes, it has not avoided major damage.” Even though, unlike hurricanes, tornado ratings are based on damage, the impact to people’s lives doesn’t necessarily correlate to the rating. If your house is destroyed, does it really matter if the tornado was rated EF4 or EF5? Your house is still destroyed. Even an EF2 or EF3 can render well-built homes unlivable.
Shrug emoji
Like Lyza et al, I have questions, not answers. The public knows about EF ratings, thanks t movies like “Twister” and “Twisters”. That bell can’t be un-rung. There’s a certain degree of American competitiveness involved, too. But maybe it’s time to stop making a big deal of it?