
Fujita Scale, or F-Scale, levels are based on the damage caused by tornado wind speed. Dr. T. Theodore Fujita developed the scale in the early 1970s. Experts caution that the F-Scale is not a completely reliable measure, due to difficulties in precisely judging wind speeds.
Engineers and meteorologists have recently come up with a more accurate way to assess tornado damage called the Enhanced F-Scale. The new scale was put into effect February 7, 2007. In the Enhanced F-scale, there are customized standards for the different types of structures damaged in the tornado's path. As with the original F-scale, the enhanced version will rate the tornado as a whole based on most intense damage within the path. When determining the EF-rating, the EF-scale begins with the 28 Damage Indicators. Each of these indicators has a brief description of the typical structure for that category. They decided when assessing damage that it was important to continue to support and maintain the original F-scale, but that surveys should include additional data not used before, such as:
Enhanced F Scale Wind Speeds
| Old Indicator | New Indicator | ||
|---|---|---|---|
| F Number | Wind Speed (mph) | EF Number | Wind Speed (mph) |
| 0 | 45 - 78 | 0 | 65 - 85 |
| 1 | 79 - 117 | 1 | 86 - 110 |
| 2 | 118 - 161 | 2 | 111 - 135 |
| 3 | 162 - 209 | 3 | 136 - 165 |
| 4 | 210 - 261 | 4 | 166 - 200 |
| 5 | 262 - 317 | 5 | Over 200 |
Enhanced F Scale Damage Indicators
| Number | Damage Indicator | Abbreviation |
|---|---|---|
| 1 | Small barns, farm outbuildings | SBO |
| 2 | One- or two-family residences | FR12 |
| 3 | Single-wide mobile home (MHSW) | MHSW |
| 4 | Double-wide mobile home | MHDW |
| 5 | Apt, condo, townhouse (three stories or less) | ACT |
| 6 | Motel | M |
| 7 | Masonry apt. or motel | MAM |
| 8 | Small retail building (fast food) | SRB |
| 9 | Small professional (doctor office, branch bank) | SPB |
| 10 | Strip mall | SM |
| 11 | Large shopping mall | LSM |
| 12 | Large, isolated ("big box") retail bldg. | LIRB |
| 13 | Automobile showroom | ASR |
| 14 | Automotive service building | ASB |
| 15 | School - one-story elementary (interior or exterior halls) | ES |
| 16 | School - junior or senior high school | JHSH |
| 17 | Low-rise (1-4 story) building | LRB |
| 18 | Mid-rise (5-20 story) building | MRB |
| 19 | High-rise (over 20 stories) | HRB |
| 20 | Institutional building (hospital, govt. or university) | IB |
| 21 | Metal building system | MBS |
| 22 | Service station canopy | SSC |
| 23 | Warehouse (tilt-up walls or heavy timber) | WHB |
| 24 | Transmission line tower | TLT |
| 25 | Free-standing tower | FST |
| 26 | Free standing pole (light, flag, luminary) | FSP |
| 27 | Tree - hardwood | TH |
| 28 | Tree - softwood | TS |
See also: the Saffir-Simpson scale
RadarsSee where weather is happening using our live interactive radars.
SkyNews 9 HDWhen there is breaking news across the state SkyNEWS 9 HD can be first on the scene.
Storm ZoneWatch tornadoes tear across Oklahoma and learn how to stay safe!
Video
Video
Video
Video
Video



