The Tornado Project

[William Monfredo]

Was not expecting a letter, but I got one in the mail today from Tom Grazulis. He's still working on volume 1, the significant tornadoes from the years 1680 to 1973. He's shooting for publication in 2026.
He's got another batch (100 or so) of copies of volume 2 printed, the strong and violent storms from 1974-2022. He says sales are unpredictable. I had the original big green book and the paperback supplement, but I lost them in a Gulf Coast hurricane in 2005. So, I figured why not order a copy of this one. The Tornado Project made a substantial chunk of change as you may remember with the video collections back in the day.

 

[William Monfredo]

For those of you that have the latest, interesting book...read on. I have some ideas about the Outbreak Intensity Scale (OIS) rankings provided at the end. Grazulis weighted the tornadoes in the outbreak list by using what he calls “multipliers.” He utilizes the numbers 2, 5, 10, and 15 as coefficients for the EF-2, EF3, EF-4 and EF-5 storms, respectively, before tallying. It provided some facility and spread for him.

I thought it might be fun to come up with a physical, scientific reason to create such numbers. Could there be different multipliers that would yield a different ranking? First, we know the man-made, lower-bound windspeed of the EF-numbers. We might choose to use that because we don’t know the range of EF-5. And, it’s also true that wind pressure varies as the square of its velocity.

So given these, I came up with new coefficients of 2, 3, 4.5 and 6.5 for the EF2-EF5 storms in the outbreaks. These are different & lower for the EF-3s, EF-4s, and EF-5s compared to the larger, Grazulis' multipliers. I haven’t created a spreadsheet, but it could be interesting to see how the rankings change / shift with these new numbers applied to those significant tornadoes in the listed outbreaks.