Where Have the EF5s Gone? A Closer Look at the "Drought" of the Most Violent Tornadoes in the United States

Details

• Journal Title:
  Bulletin of the American Meteorological Society
• Personal Author:
  Lyza, Anthony W. ; Brooks, Harold E. ; Krocak, Makenzie J.
• NOAA Program & Office:
  OAR (Oceanic and Atmospheric Research) ; NSSL (National Severe Storms Laboratory) ; OAR (Oceanic and Atmospheric Research)
• Description:
  As of January 2025, the United States has gone over 11 years without the occurrence of a tornado rated enhanced Fujita 5 scale (EF5) on the EF scale, constituting the longest "drought" in F5/EF5-rated tornadoes since the beginning of official records (1950). This article places the drought of 5-rated tornadoes in the context of a long-term tornado climatology. A key breakpoint exists between how the legacy F scale and the EF scale handle the complete destruction and sweeping away of single-family homes, with standard "well-constructed" homes being swept away constituting F5 damage on the F scale but only EF4 damage on the EF scale. To illustrate this point, adjusting the lower bound of EF5 on the EF scale from 201 to 190 mph or increasing all from 190-200-mph EF4s to >200-mph EF5s to account for this breakpoint in the handling of single-family homes would lead to consistent 5-level rating assignments from 1880 to the present day. Furthermore, contextual evidence that was used to aid in identifying 5-level damage in the F-scale and early EF-scale eras could assist in identifying top-tier intensity tornadoes. These findings ultimately lead to questions regarding what the highest possible rating of a tornado should represent from both physical and societal perspectives. Significance Statement This article explores the lack of EF5 tornadoes in the past decade and methods that could be useful in discriminating top-tier tornado intensities. We show evidence that the lack of EF5-rated tornadoes in the past decade is less due to a weakening of tornadoes and likely attributable to stricter application of the enhanced Fujita scale. An 11-mph downward adjustment in the threshold for EF5 estimated wind speed would make the rate of EF5 ratings since 2013 consistent with a long-time climatology back to 1880. We contemplate the implications of these findings on the tornado climatology and how the meteorological and engineering communities really desire to identify top-tier-intensity tornadoes.
• Source:
  Bulletin of the American Meteorological Society, 106(8), E1708-E1716
• DOI:
  https://doi.org/10.1175/bams-d-24-0066.1
• ISSN:
  0003-0007 ; 1520-0477
• Format:
  pdf
• Publisher:
  American Meteorological Society
• Document Type:
  Journal Article
• Rights Information:
  Other
• Compliance:
  Library
• Download URL:
  https://repository.library.noaa.gov/view/noaa/75312/noaa_75312_DS1.pdf
• File Type:
  [PDF - 1.16 MB]
• Collection(s):
  Office of Oceanic and Atmospheric Research (OAR)
• Main Document Checksum:
  urn:sha-512:78891669db2d0f94dad6f6012738883c98e853dfdf9d89b8b31218ff0f0d69207e5bf0572de1710f0c48bab157d4f174735553e570064a35c1859e7cdbbbfd6e