Enhanced Fujita Scale
Also called: EF scale, EF rating
The Enhanced Fujita (EF) scale rates tornadoes from EF0 to EF5 based on the damage they cause. Surveyors compare the damage to 28 kinds of buildings, structures, and trees against expected levels of damage, then estimate the 3-second wind gust responsible. EF0 means estimated gusts of 65 to 85 mph, and EF5 means over 200 mph.
Why It Matters
The EF rating is the standard shorthand for how strong a tornado was. It is assigned after the storm, from a damage survey, because tornado winds are almost never measured directly. The scale is a set of wind estimates based on damage, not measurements.
The EF scale replaced the original Fujita (F) scale in the United States on 1 February 2007.
Enhanced Fujita Scale and the Original Fujita Scale
| Rating | EF scale: estimated 3-second gust | Original F scale: fastest quarter-mile wind |
|---|---|---|
| 0 | 65 to 85 mph | 40 to 72 mph |
| 1 | 86 to 110 mph | 73 to 112 mph |
| 2 | 111 to 135 mph | 113 to 157 mph |
| 3 | 136 to 165 mph | 158 to 207 mph |
| 4 | 166 to 200 mph | 208 to 260 mph |
| 5 | Over 200 mph | 261 to 318 mph |
What a Rating Does Not Tell You
- It is not a forecast. A tornado gets its rating after a damage survey, so the number is unknown while the tornado is on the ground.
- It is not a measurement. The wind speeds are estimates inferred from damage.
- It depends on what was hit. The rating comes from damage, so a tornado that crosses open country with little to damage can be rated lower than its true strength.
- There is no EF6. EF5 has no upper limit.
Frequently Asked Questions
What wind speed is an EF5 tornado?
An EF5 tornado has estimated 3-second gusts over 200 mph. It is the highest rating on the Enhanced Fujita scale, and there is no EF6.
What is the difference between the Fujita scale and the Enhanced Fujita scale?
The original Fujita scale assigned wind speeds, up to 261 to 318 mph for an F5, that were never scientifically verified. The Enhanced Fujita scale, used in the United States since 1 February 2007, estimates 3-second gusts from 28 damage indicators. Its wind speeds for the higher ratings are lower than the old scale's.
Who decides a tornado's EF rating?
National Weather Service survey teams. They examine the damage after the storm, match it to the scale's damage indicators, and assign the rating from the worst damage the tornado caused.
Related Terms
Tornado
A tornado is a violently rotating column of air in contact with the ground, extending from a thunderstorm. Tornadoes are rated from EF0 to EF5 on the Enhanced Fujita scale by the damage they cause. Most last less than 10 minutes, but the strongest can stay on the ground for more than an hour.
Supercell
A supercell is a thunderstorm with a deep, persistently rotating updraft called a mesocyclone. Supercells are the most dangerous type of thunderstorm: they produce nearly all significant tornadoes in the United States and most hail larger than golf balls, along with damaging winds and flash flooding.
Debris Ball
A radar signature showing a concentrated area of debris lofted by a tornado. Debris balls appear as a circular area of high reflectivity collocated with rotation and confirm a tornado is on the ground causing damage.
Funnel Cloud
A rotating cone-shaped cloud extending downward from the base of a thunderstorm but not reaching the ground. When a funnel cloud touches the ground, it becomes a tornado.
Mesocyclone
A rotating vortex of air within a supercell thunderstorm, typically 2-6 miles in diameter. Mesocyclones are detected by Doppler radar and indicate the potential for tornado development.
Saffir-Simpson Scale
The Saffir-Simpson Hurricane Wind Scale rates hurricanes from Category 1 to Category 5 by maximum sustained wind speed. Category 1 starts at 74 mph and Category 5 at 157 mph, and Category 3 and higher are called major hurricanes. The scale measures wind only: it does not account for storm surge, rainfall flooding, or tornadoes.
Enhanced Fujita Scale: Guides and Explainers
These explainers connect this definition to real-world forecasting and decision-making.
In-depth guide
How Tornadoes Form: Types, EF Scale, and Safety
Learn how tornadoes form from supercell thunderstorms, the Enhanced Fujita scale, types of tornadoes, and critical safety steps to protect yourself.
Weather Education
Understanding Flash Floods: Causes, Warnings, and Safety
Learn what causes flash floods, how to spot the risk on radar, the difference between watches, warnings, and emergencies, and critical safety steps that save lives.
Weather Education
Why Dew Point Matters More Than Humidity
Learn why dew point temperature is a better measure of moisture comfort than relative humidity, how to interpret dew point readings, and when high dew points become dangerous.
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