From 1971 to 2007, the United States used the original (F-Scale), developed by Dr. Tetsuya Theodore Fujita. However, meteorologists realized the wind speed estimates on the original scale were inaccurate (they overestimated wind speeds required to cause damage).
Surveyors look at specific types of structures (Damage Indicators) and determine how badly they were hit.
Because we cannot easily place sensors inside a vortex that travels at 200 mph, we use a "damage-based" ranking system. Here is a deep dive into how we rank these storms and why the system changed. The Origins: The Fujita Scale (F-Scale)
| EF Rating | 3-Second Gust (mph) | 3-Second Gust (km/h) | Damage Description | Typical Damage Examples | |-----------|---------------------|----------------------|--------------------|--------------------------| | | 65–85 | 105–137 | Light damage | Broken tree branches; shallow-rooted trees toppled; damaged gutters/siding. | | EF1 | 86–110 | 138–177 | Moderate damage | Roofs severely stripped; mobile homes overturned or badly damaged; exterior doors lost. | | EF2 | 111–135 | 178–217 | Significant damage | Roofs torn off well-constructed houses; mobile homes completely destroyed; large trees snapped or uprooted. | | EF3 | 136–165 | 218–266 | Severe damage | Entire stories of well-built homes destroyed; heavy cars lifted off ground; trains overturned. | | EF4 | 166–200 | 267–322 | Devastating damage | Well-constructed houses leveled; cars thrown like projectiles; trees debarked. | | EF5 | >200 | >322 | Incredible damage | Strong frame houses swept away; automobile-sized missiles fly >100 meters; high-rise buildings have significant structural deformation. |
| EF Rating | % of all tornadoes | Characteristics | |-----------|--------------------|------------------| | EF0 | ~50% | Brief, narrow, low damage | | EF1 | ~35% | Common in supercells | | EF2 | ~10% | Significant damage | | EF3 | ~4% | Severe, dangerous | | EF4 | ~0.8% | Devastating (only ~50 per decade) | | EF5 | ~0.1% | Extremely rare (last confirmed: May 20, 2013 – Moore, OK) |
Whole frame houses are leveled; cars are thrown significant distances.
Entire stories of well-constructed houses destroyed; severe damage to large buildings like shopping malls. EF4 166–200 mph
| Feature | Fujita (F) Scale | Enhanced Fujita (EF) Scale | |-------------------------|----------------------------------|-------------------------------------| | | 1971 (operationally 1973) | 2007 | | Wind speed basis | Estimated, unverified | Engineering-based, calibrated | | Number of DIs | ~6 general categories | 28 specific DIs | | Construction quality | Not considered | Explicitly accounted for | | Upper bound (F5/EF5) | 261–318 mph (420–512 km/h) | >200 mph (>322 km/h) | | Scientific basis | Low | High (wind engineering data) |
Tornado Ranking System !!hot!! Jun 2026From 1971 to 2007, the United States used the original (F-Scale), developed by Dr. Tetsuya Theodore Fujita. However, meteorologists realized the wind speed estimates on the original scale were inaccurate (they overestimated wind speeds required to cause damage). Surveyors look at specific types of structures (Damage Indicators) and determine how badly they were hit. Because we cannot easily place sensors inside a vortex that travels at 200 mph, we use a "damage-based" ranking system. Here is a deep dive into how we rank these storms and why the system changed. The Origins: The Fujita Scale (F-Scale) tornado ranking system | EF Rating | 3-Second Gust (mph) | 3-Second Gust (km/h) | Damage Description | Typical Damage Examples | |-----------|---------------------|----------------------|--------------------|--------------------------| | | 65–85 | 105–137 | Light damage | Broken tree branches; shallow-rooted trees toppled; damaged gutters/siding. | | EF1 | 86–110 | 138–177 | Moderate damage | Roofs severely stripped; mobile homes overturned or badly damaged; exterior doors lost. | | EF2 | 111–135 | 178–217 | Significant damage | Roofs torn off well-constructed houses; mobile homes completely destroyed; large trees snapped or uprooted. | | EF3 | 136–165 | 218–266 | Severe damage | Entire stories of well-built homes destroyed; heavy cars lifted off ground; trains overturned. | | EF4 | 166–200 | 267–322 | Devastating damage | Well-constructed houses leveled; cars thrown like projectiles; trees debarked. | | EF5 | >200 | >322 | Incredible damage | Strong frame houses swept away; automobile-sized missiles fly >100 meters; high-rise buildings have significant structural deformation. | | EF Rating | % of all tornadoes | Characteristics | |-----------|--------------------|------------------| | EF0 | ~50% | Brief, narrow, low damage | | EF1 | ~35% | Common in supercells | | EF2 | ~10% | Significant damage | | EF3 | ~4% | Severe, dangerous | | EF4 | ~0.8% | Devastating (only ~50 per decade) | | EF5 | ~0.1% | Extremely rare (last confirmed: May 20, 2013 – Moore, OK) | From 1971 to 2007, the United States used Whole frame houses are leveled; cars are thrown significant distances. Entire stories of well-constructed houses destroyed; severe damage to large buildings like shopping malls. EF4 166–200 mph Surveyors look at specific types of structures (Damage | Feature | Fujita (F) Scale | Enhanced Fujita (EF) Scale | |-------------------------|----------------------------------|-------------------------------------| | | 1971 (operationally 1973) | 2007 | | Wind speed basis | Estimated, unverified | Engineering-based, calibrated | | Number of DIs | ~6 general categories | 28 specific DIs | | Construction quality | Not considered | Explicitly accounted for | | Upper bound (F5/EF5) | 261–318 mph (420–512 km/h) | >200 mph (>322 km/h) | | Scientific basis | Low | High (wind engineering data) | |