Enhanced Fujita scale

The seven categories for the EF scale are listed below, in order of increasing intensity. Although the wind speeds and photographic damage examples are updated, the damage descriptions given are based on those from the Fujita scale, which are more or less still accurate. However, for the actual EF scale in practice, damage indicators (the type of structure which has been damaged) are predominantly used in determining the tornado intensity.[8]

Scale	Wind speed estimate[9]		Potential damage	Example of damage
	mph	km/h
EFU	N/A	N/A	No surveyable damage. Intensity cannot be determined due to a lack of information. This rating applies to tornadoes that traverse areas with no damage indicators, cause damage in an area that cannot be accessed by a survey, or cause damage that cannot be differentiated from that of another tornado.[5]	N/A
EF0	65–85	105–137	Minor damage. Peels surface off some roofs; some damage to gutters or siding; branches broken off trees; shallow-rooted trees pushed over. Confirmed tornadoes with no reported damage (i.e., those that remain in open fields) have also been rated EF0. While permanent buildings generally suffer only minor damage, unprotected mobile homes or trailers may sustain moderate to serious damage.[10]
EF1	86–110	138–177	Moderate damage. Roofs severely stripped; mobile homes overturned or badly damaged; loss of exterior doors; windows and other glass broken.
EF2	111–135	178–217	Considerable damage. Roofs torn off from well-constructed houses; foundations of frame homes shifted; mobile homes completely destroyed; large trees snapped or uprooted; light-object missiles generated; cars lifted off ground.
EF3	136–165	218–266	Severe damage. Entire stories of well-constructed houses destroyed; severe damage to large buildings such as shopping malls; trains overturned; trees debarked; heavy cars lifted off the ground and thrown; structures with weak foundations are badly damaged.
EF4	166–200	267–322	Devastating damage. Well-constructed and whole frame houses completely leveled; some frame homes may be swept away; cars and other large objects thrown and small missiles generated.
EF5	>200	>322	Incredible damage. Well-built frame houses destroyed with foundations swept clean of debris; steel-reinforced concrete structures are critically damaged; tall buildings collapse or have severe structural deformations; cars, trucks, and trains can be thrown approximately 1 mile (1.6 km).

The new scale takes into account the quality of construction and standardizes different kinds of structures. The wind speeds on the original scale were deemed by meteorologists and engineers as being too high, and engineering studies indicated that slower winds than initially estimated cause the respective degrees of damage.[12] The old scale lists an F5 tornado as wind speeds of 261–318 mph (420–512 km/h), while the new scale lists an EF5 as a tornado with winds above 200 mph (322 km/h), found to be sufficient to cause the damage previously ascribed to the F5 range of wind speeds. None of the tornadoes in the United States recorded before February 1, 2007, will be re-categorized.

Essentially, there is no functional difference in how tornadoes are rated. The old ratings and new ratings are smoothly connected with a linear formula. The only differences are adjusted wind speeds, measurements of which were not used in previous ratings, and refined damage descriptions; this is to standardize ratings and to make it easier to rate tornadoes which strike few structures. Twenty-eight Damage Indicators (DI), with descriptions such as "double-wide mobile home" or "strip mall", are used along with Degrees of Damage (DOD) to determine wind estimates. Different structures, depending on their building materials and ability to survive high winds, have their own DIs and DODs. Damage descriptors and wind speeds will also be readily updated as new information is learned.[11] Some differences do exist between the two scales in the ratings assigned to damage. An EF5 rating on the new scale requires a higher standard of construction in houses than does an F5 rating on the old scale. So, the complete destruction and sweeping away of a typical American frame home, which would likely be rated F5 on the Fujita scale, would be rated EF4 or lower on the Enhanced Fujita scale.[13]

Since the new system still uses actual tornado damage and similar degrees of damage for each category to estimate the storm's wind speed, the National Weather Service states that the new scale will likely not lead to an increase in a number of tornadoes classified as EF5. Additionally, the upper bound of the wind speed range for EF5 is open—in other words, there is no maximum wind speed designated.[8]

For purposes such as tornado climatology studies, Enhanced Fujita scale ratings may be grouped into classes.[14][15][16]

The table shows other variations of the tornado rating classifications based on certain areas.

• Edwards, Roger; J. G. LaDue; J. T. Ferree; K. Scharfenberg; C. Maier; W. L. Coulbourne (2013). "Tornado Intensity Estimation: Past, Present, and Future". Bull. Amer. Meteor. Soc. 94 (5): 641–53. Bibcode:2013BAMS...94..641E. doi:10.1175/BAMS-D-11-00006.1.

Wikimedia Commons has media related to Enhanced Fujita Scale.

• National Oceanic and Atmospheric Administration
  • NOAA National Weather Service Improves Tornado Rating System at NOAA News
  • The Enhanced Fujita Scale (EF Scale) at Storm Prediction Center
  • EF-Scale Training at The Warning Decision Training Branch of National Weather Service (NWS)
  • The Enhanced Fujita Tornado Scale at National Climatic Data Center
  • The Tornado: An Engineering-Oriented Perspective (NWS SR147)
  • A Guide for Conducting Convective Windstorm Surveys (NWS SR146)
• Fujita Scale Enhancement Project (Wind Science and Engineering Research Center at Texas Tech University)
• Symposium on the F-Scale and Severe-Weather Damage Assessment at American Meteorological Society
• A Guide to F-Scale Damage Assessment, MetEd, University Corporation for Atmospheric Research
• Mitigation Assessment Team Report: Midwest Tornadoes of May 3, 1999 (Federal Emergency Management Agency)