Climate at a Glance: Tornadoes

A tornado in eastern North Dakota on June 27, 2015. Photo: NOAA NWS, Amanda L. Hill

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Key Takeaways:

  • The number of tornadoes has been declining for the past 45 years.
  • The number of strong tornadoes, F3 or higher, has been dramatically declining for the past 45 years.
  • In 2017-2018, the U.S. set a record for the longest period in history without a tornado death.
  • In 2017-2018, the U.S. set a record for the longest period in history without an F3 or stronger tornado.
  • The two record-low years for number of tornadoes both occurred this past decade – 2014 and 2018.
  • According to a reports by the United Nations, “There is low confidence in observed trends in small spatial-scale phenomena such as tornadoes.”

Short Summary:

Tornadoes typically form when very cold, dry air clashes with warm, humid air. Climate change warms the Arctic more than the tropics and subtropics, resulting in less of a clash between cold Arctic air masses and warm Gulf of Mexico air masses. As a result, fewer and less violent tornadoes are occurring today than in previous periods, despite media
claims that tornadoes are getting more frequent, stronger, or both.1,2

The number of tornadoes in the United States, as well as in other countries, has been slowly declining for the past 45 years. At the same time, the number of strong to violent tornadoes, EF3 or higher, has been dramatically declining for the past 45 years. (See Figure 1.) In fact, the United States set a record in 2017–18 for the longest period in recorded history without a tornado death, and it set a record for the longest period in history (306 days) without an EF3 or stronger tornado.3,4 The two record-low years for tornado strikes in the United States both occurred this past decade, in 2014 and 2018.5

Further, even the U.N. Intergovernmental Panel on Climate Change has acknowledged, “There is low confidence in observed trends in small spatial-scale phenomena such as tornadoes.”6

Figure 1. U.S. Annual Count of Strong to Violent Tornadoes (EF3+), 1970–2020

Figure 1. This figure shows the frequency of strong to violent tornadoes (tornadoes registering EF3 or
stronger) has been declining since the early 1970s. Sources: Graph by Anthony Watts using official
NOAA/Storm Prediction Center data.7,8,9

References:

  1. Nsikan Akpan, “Is Climate Change Making U.S. Tornadoes Worse?,” Public Broadcasting
    Service, March 5, 2019, https://www.pbs.org/newshour/science/is-climate-changemaking-
    u-s-tornadoes-worse
  2. Bob Berwyn, “Is Climate Change Fueling Tornadoes?,” Inside Climate News, May
    30, 2019, https://insideclimatenews.org/news/30052019/tornado-climate-changeconnection-
    science-research-data
  3. Doyle Rice, “U.S. Sets Record of 246 Straight Days without a Tornado Death,” USA
    Today, January 17, 2018, https://www.usatoday.com/story/weather/2018/01/17/u-ssets-
    record-246-straight-days-without-tornado-death/1041125001
  4. Chris Dolce, “Record-Long Streak With No EF3 or Stronger Tornadoes in the U.S. Ends
    in Jacksonville, Alabama,” The Weather Channel, March 18, 2018, https://weather.
    com/storms/tornado/news/2018-03-21-jacksonville-alabama-tornado-ends-ef3-unitedstates-
    drought
  5. Doyle Rice, “2018 Was an All-Time Record Quiet Year for Tornadoes in the U.S.,” USA
    Today, December 28, 2018, https://www.usatoday.com/story/news/nation/2018/12/28/
    tornadoes-set-record-lows-2018-only-10-deaths-us/2431360002
  6. U.N. Intergovernmental Panel on Climate Change, Changes in Climate Extremes and
    Their Impacts on the Natural Physical Environment, Chapter 3, 2018, accessed August
    16, 2021, https://www.ipcc.ch/site/assets/uploads/2018/03/SREX-Chap3_FINAL-1.pdf
  7. National Oceanic and Atmospheric Administration, “Historical Records and Trends,”
    accessed September 1, 2021, https://www.ncdc.noaa.gov/climate-information/
    extreme-events/us-tornado-climatology/trends
  8. Daniel McCarthy and Joseph Schaefer, “Tornado Trends over the Past Thirty Years,”
    NOAA, National Weather Service, NWS, NCEP, Storm Prediction Center, accessed
    8/16/21, https://www.spc.noaa.gov/publications/mccarthy/tor30yrs.pdf
  9. Graph data from National Oceanic and Atmospheric Administration’s National Weather Service,
    Storm Prediction Center website, accessed August 16, 2021, https://www.spc.noaa.gov/wcm

Climate At A Glance is a Project of The Heartland Institute

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