There Were Once F6-Rated Tornadoes, But Not Anymore… Here’s Why

When it comes to severe weather, people around here talk about EF5 tornadoes like they’re just part of the deal.

They’re not.

They’re rare. Like, globally rare.

Depending on how you count them, there have only been a few dozen true F5 or EF5 tornadoes ever recorded, and yeah, a good chunk of those happened right here in the U.S. Oklahoma’s had its share, Texas too, but even then… it’s still a short list.

Which makes the whole “what’s stronger than an EF5?” question a little wild to think about.

So here’s the quick backstory.

Back in 1971, a meteorologist named Ted Fujita decided we needed a better way to rate tornadoes. Before that, it was basically guesswork and stories passed down. He came up with the Fujita Scale, tying estimated wind speeds to the kind of damage a tornado leaves behind.

That’s where the original F0 through F5 ratings came from.

And yeah… technically, the math went higher. Way higher. There was even an F12 on paper at one point, which sounds more like science fiction than weather.

But in the real world, F5 was already pushing the limits of what made sense.

Over time, scientists realized something important. You can’t reliably measure wind speed inside a tornado the way you think you can. Not directly. So instead of chasing exact numbers, they shifted focus to what actually matters, the damage.

That’s how we ended up with the Enhanced Fujita Scale, the EF scale we use today. Same basic idea, but now it’s built around what gets destroyed and how completely it gets wiped out. It runs from EFU, meaning unknown damage, up to EF5, which is total destruction. Clean slabs. Nothing left but a foundation and a mess of debris downwind.

And that’s where things kind of hit a wall.

Once you’ve hit “total destruction,” there’s not really a next step.

Still… there have been a couple of moments in history where scientists at least entertained the idea of something beyond that.

The big one everybody around here remembers is the May 3, 1999 tornado, the one that tore through Bridge Creek and Moore. That storm carved a path from near Amber all the way to Midwest City and left behind miles of neighborhoods that just… weren’t there anymore.

At one point, Doppler radar clocked winds at 321 miles per hour. For a minute, it looked like it might break the scale entirely. Some early estimates even nudged into what would’ve been “F6” territory.

But when everything was reviewed later, the official rating stayed at F5. Not because it wasn’t strong enough, but because the scale doesn’t really have anywhere else to go.

Official F6 Twisters

There were also a couple of these, but they've all been downgraded over time. One in Lubbock, Texas in 1970 and another in Xenia, Ohio in 1974, where damage looked extreme enough that they were rated F6 during early analysis.

Same outcome there too. Both were eventually pulled back to F5.

And the reason is pretty simple once you think about it.

F5, and now EF5, already means total destruction. Not “really bad.” Not “worse than usual.” It means everything that can be destroyed, is destroyed.

The old idea for F6 was “unimaginable destruction.”

Problem is… you can’t measure unimaginable. There’s no scale for it. No clean way to define it, compare it, or apply it consistently.

So science backed away from it.

Add in the fact that earlier assumptions about tornado wind speeds were way off, people used to think they could hit 500 miles per hour, and it all starts to make more sense. As radar improved, especially with Doppler, we learned the numbers were still extreme, just not that extreme.

So today, EF5 stands as the ceiling. Not because tornadoes couldn’t theoretically get stronger, but because once you’ve flattened everything, there’s nothing left to compare.

And honestly… that’s probably for the best.

If the day ever comes where we need something above EF5, that’s not a scale problem anymore. That’s a “hope you weren’t anywhere near it” problem.