The F5 and EF5 are the top ratings on two different tornado intensity scales. Both describe "incredible" damage. The key difference: F5 (Fujita Scale, 1971-2007) required 261+ mph winds; EF5 (Enhanced Fujita, 2007-present) requires 200+ mph. The change was based on engineering research showing the original F-scale wind speeds were too high.
| Feature | F5 (Fujita) | EF5 (Enhanced Fujita) |
|---|---|---|
| Wind speed threshold | 261+ mph | 200+ mph (3-sec gust) |
| In effect | 1971 - Feb 1, 2007 | Feb 1, 2007 - present |
| Created by | Ted Fujita | NWS + engineers |
| Rating method | Damage indicators | 28 damage indicators + degrees of damage |
| Damage description | "Incredible damage" | "Incredible damage" |
| Foundation sweeping | Required | Required |
Ted Fujita developed the original Fujita Scale in 1971 using estimates of the wind speeds needed to produce various damage indicators. The estimates were based on the limited engineering research available at the time. His scale set F5 at 261+ mph.
By the 1990s, wind engineering research had advanced. Studies of tornado damage (particularly the 1999 Bridge Creek-Moore F5) showed that the damage Fujita attributed to 261+ mph winds could actually occur at 200+ mph. In other words: F5 wind estimates were too high.
The NWS worked with wind engineers throughout the 2000s to develop a revised scale that better matched modern damage-to-wind-speed relationships. The Enhanced Fujita Scale went into effect on February 1, 2007.
Yes. Every historical F5 tornado would still be rated at the highest tier (EF5) under the modern scale. The damage descriptions haven't changed - only the wind speed estimates. So F5 events like:
...would all still be EF5 today, but with lower (more accurate) wind speed estimates.
The Enhanced Fujita Scale uses 28 damage indicators (DIs), each with defined "degrees of damage" (DODs). Examples:
Each DI has a range of DODs, each mapped to a range of wind speeds. Surveyors document damage, identify the DI and DOD, and derive an estimated wind speed. The tornado's rating is the highest DOD found along its path.
The change from F to EF affects historical comparison. When comparing modern EF5s (like Joplin 2011 at ~200 mph) to historical F5s (like Waco 1953 estimated at 300 mph), the modern events look weaker by wind speed - but the damage they produced was comparable. Only the estimates changed.
For public safety purposes, F5 and EF5 mean the same thing: a tornado capable of leveling any residential structure and requiring purpose-built shelter for survival.
The last officially rated EF5 in the US was Moore 2013. Since then, several tornadoes (Bassfield 2020, Mayfield 2021, Rolling Fork 2023) have shown damage consistent with EF5 but were rated EF4. Meteorologists debate whether the EF Scale's damage-indicator requirements have become too conservative. Full list of every EF5 ->
Comparing tornado severity internationally is complicated by these scale differences.
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