Sign In or Register Here


5 plus zero

Please enter your e-mail address below. We will email you a link to reset your password.

1 plus six

To complete your registration, please verify your email address.

7 minus four

We have sent an email to the address you provided. Please click the link in the email to confirm your email address.

Your account has been marked for password reset. Please change your password.

6 minus three

Only registered ICC members have access to this article at this time.

Explore all the benefits that ICC Membership has to offer and become a member today to gain access to this exciting content.

If you're already an ICC member Sign In Now.


Can We Help?
  • Reset My Password
  • I Need More Help
ICC Homepage
  • Family of Solutions
  • ICCSafe
  • myICC
  • Digital Codes
  • cdpACCESS
  • Store
  • Support
  • Journal
Skip to Main Content
  • ICC Main
  • myICC
  • BSJ
  • Journal
  • Store
  • Store
  • cdpACCESS
  • cdpACCESS
  • Digital Codes
  • Help
  • Help
    • Family of Solutions
    • ICCSafe
    • myICC
    • Digital Codes
    • cdpACCESS
    • Store
    • Support
    • Journal
Building Safety Journal Homepage Building Safety Journal Homepage
Building Safety Journal Homepage Building Safety Journal Homepage
  • Archive
    • June, 2022 Articles
    • May, 2022 Articles
    • April, 2022 Articles
    • March, 2022 Articles
    • Febuary, 2022 Articles
    • January, 2022 Articles
    • 2022 Articles
    • 2021 Articles
  • Browse by Category
    • Deep Dives
    • Member News
    • Personal Perspectives
    • Quick Hits
    • Technical Topics
    • Press Releases
    • Sponsored Content
    • View All
  • Browse by Topic
    • Buildings, Construction, Architecture/Design
    • Fire, Wildland-Urban Interface
    • Plumbing, Mechanical, Fuel Gas, Pools/Spas
    • Energy, Solar, Green, Sustainability
    • Disaster Preparedness, Mitigation, Resiliency
  • Subscribe
    • Family of Solutions
    • ICCSafe
    • myICC
    • Digital Codes
    • cdpACCESS
    • Store
    • Support
    • Journal

Join today!

Keep up-to-date on crucial industry news, innovative training and expert technical advice with a free subscription to the award-winning Building Safety Journal.

Subscribe
  • Archive
    • June, 2022 Articles
    • May, 2022 Articles
    • April, 2022 Articles
    • March, 2022 Articles
    • Febuary, 2022 Articles
    • January, 2022 Articles
    • 2022 Articles
    • 2021 Articles
  • Browse by Category
    • Deep Dives
    • Member News
    • Personal Perspectives
    • Quick Hits
    • Technical Topics
    • Press Releases
    • Sponsored Content
    • View All
  • Browse by Topic
    • Buildings, Construction, Architecture/Design
    • Fire, Wildland-Urban Interface
    • Plumbing, Mechanical, Fuel Gas, Pools/Spas
    • Energy, Solar, Green, Sustainability
    • Disaster Preparedness, Mitigation, Resiliency
  • Subscribe
  • Archive
    • June, 2022 Articles
    • May, 2022 Articles
    • April, 2022 Articles
    • March, 2022 Articles
    • Febuary, 2022 Articles
    • January, 2022 Articles
    • 2022 Articles
    • 2021 Articles
  • Browse by Category
    • Deep Dives
    • Member News
    • Personal Perspectives
    • Quick Hits
    • Technical Topics
    • Press Releases
    • Sponsored Content
    • View All
  • Browse by Topic
    • Buildings, Construction, Architecture/Design
    • Fire, Wildland-Urban Interface
    • Plumbing, Mechanical, Fuel Gas, Pools/Spas
    • Energy, Solar, Green, Sustainability
    • Disaster Preparedness, Mitigation, Resiliency
  • Subscribe

Scientists fear tornadoes are getting worse

March 28th, 2019
by Tara Lukasik
  • Quick Hits

North America sees dozens of tornado outbreaks annually, and the number of tornadoes that occur per outbreak seems to be increasing. A series of some three dozen tornadoes — often called a tornado “outbreak” or “swarm” — touched down in Alabama, Georgia, South Carolina and the Florida Panhandle on March 3, 2019, leaving 23 people dead in Lee County, Ala., with dozens still missing, and homes and property throughout the Southeastern U.S. totally destroyed. While the exact number of tornadoes has yet to be determined, it was undoubtedly the deadliest tornado day since 2013.

The recent tornado outbreak caused double the number of tornado-related deaths that the U.S. saw in the entirety of last year and confirms a trend that climatologists and scientists have been monitoring for years — tornado outbreaks in the Southeastern U.S. are getting worse. A new paper published by the International Research Institute for Climate and Society reports that the average number of tornadoes per outbreak has grown by more than 40 percent over the last half century. The likelihood of extreme outbreaks — those with many tornadoes — has also increased.

While the study’s authors said they do not know what is driving the changes, many scientists attribute the changes to an increase in the frequency of warmer-climate atmospheric conditions favorable to tornadoes, although the right conditions don’t always guarantee a tornado will occur. The research also tracks where tornado outbreaks might become more intense. The data suggests that the Southeastern U.S. — particularly Alabama, Louisiana and Mississippi — are seeing trends of increasing activity.

“When it comes to tornadoes, almost everything terrible that happens, happens in outbreaks,” said Michael Tippett, lead author of the study, in a press release. “If outbreaks contain more tornadoes on average, then the likelihood they’ll cause damage somewhere increases.”

For this study, the authors calculated the mean number of tornadoes per outbreak for each year as well as the variance, or scatter, around this mean. They found that while the total number of tornadoes rated F/EF1 and higher each year hasn’t increased, the average number of tornadoes per outbreak has, rising from about 10 to about 15 since 1954. Between 1972 and 2010, outbreaks were associated with 79 percent of all tornado fatalities. The analysis shows that as the mean number of tornadoes per outbreak rose, the variance around that mean rose four times faster. While the mean rose by a factor of 1.5 over the last 60 years, the variance rose by a factor of more than 5. This kind of relationship between variance and mean has a name in statistics: Taylor’s power law of scaling, which is seen in everything from the distribution of stars in a galaxy to the death rates in countries and population density and securities trading. However, it is the first time anyone has shown that it applies to scaling in tornado statistics.

While the recent tornado outbreak is consistent with trends that climatologists and scientists have been seeing for several years, extreme outbreaks have become more frequent because of two factors. First, the average number of tornadoes per outbreak has gone up; second, the rapidly increasing variance, or variability, means that numbers well above the average are more common.

The twisters in Lee County, Ala., which is 80 miles north of Montgomery, Ala., injured and killed the most people in the recent outbreak and had unusual features — the two tornadoes touched down within a span of 10 minutes; and one had a path nearly a mile wide and 24 miles long (the average distance tornadoes travel is about 3.5 miles), was an EF-4 storm (the second-most severe designation), and it brought winds of 170 mph that ripped homes off of foundations. An even more deadly tornado outbreak occurred in 2011; it spawned 363 tornadoes across North America, caused $11 billion in damages and killed more than 350 people.

Click here to read the recently released damage assessment report from the Structural Extreme Event Reconnaissance Network (StEER) on the recent tornado outbreak in the Southeastern U.S.

About the Author
Tara Lukasik
Tara Lukasik is an editor for the International Code Council, working out of its Western Regional Office in Southern California. Starting with the International Conference of Building Officials as the managing editor of its Building Standards Magazine, she has more than 25 years of experience in writing and editing feature content and advancing digital newsletters and magazines from conception to completion. She is currently putting her experience to good use managing the Code Council's Building Safety Journal and its BSJ Weekly newsletter, which connects construction professionals with the Code Council community and the latest industry news and resources. A California native, she enjoys volunteering in her local community and exploring the Golden State with her husband and two spoiled dachshunds. Follow her on Twitter @ICCTLukasik and Linkedin at linkedin.com/in/taralukasik.
Submissions
Check out upcoming BSJ topics and send us articles for consideration:
Or send by email

Want to advertise in the BSJ?
Click Here

Share on Facebook
Facebook
Tweet about this on Twitter
Twitter
Share on LinkedIn
Linkedin

  • Cannabis Facilities
    Purchase Now
  • I-Code Essentials
    Purchase Now
  • Spanish I-Codes
    Purchase Now
  • 2021 I-Codes
    Purchase Now
  • Building Resilience General Code
  • Special Inspector Exam
ICC ICC
  • About
  • Contact Us
  • Subscribe

Connect With Us

    

ICC Family of Solutions

  • Quick Links
    • Member resources
    • Discussions
    • Become a member
    • Get involved in code development
    • Get certified
    • Find a job
    • Careers at ICC
    • Get a code opinion
    • Get a plan review
    • Shop ICC
    • Privacy Policy
    • License Agreement
    • User Agreement
COPYRIGHT © 2022 INTERNATIONAL CODE COUNCIL, INC. ALL RIGHTS RESERVED.
  • cdpACCESS
  • Live Chat
  • Twitter
  • Facebook
  • LinkedIn
SxVp9vtrKhTJTYSCvJkWoqzgtIZp2AxvVv-__KmLem4=.html