Tornadoes in the U.S., in Europe and elsewhere

tornadoes-hot-spots-around-the-world

Like the United States, Europe experiences its share of severe weather ranging from intense winter storms to violent thunderstorms accompanied by hail stones and even tornadoes. No continent remotely rivals North America when it comes to tornadoes. A vast majority of those tornadoes spawn within the 48 contiguous states of the U.S., mainly east of the Rocky Mountains. The Storm Prediction Center (SPC), headquartered in Norman, Oklahoma, keeps a history of tornadoes reported in the U.S. since 1950. The SPC is also situated in an area that has a relatively high frequency of strong to violent twisters. This band of intense tornadic activity, covering South Central states and most of the Midwest is referred to by the media as Tornado Alley.

tornado_alley_intense_tornadoes

Based on data pulled from the European Severe Weather Database (ESWD), 5,478 tornadoes have been reported from 1950 to 2015 in 42 countries. [Although waterspouts–generally weaker vortices over water–are included in the ESWD definition of a tornado, only those confirmed and verified, on land, were selected from the database for this article.] That comes to an average of 83 tornadoes per year in Europe. In December 2016, a research paper titled Tornadoes in Europe: An underestimated threat became available online with the purpose of raising public awareness as to the underestimated and under-reported threat of these funnel-shaped maelstroms of dangerous winds. Tornadoes were under-reported in the U.S. as well during earlier decades when reports of severe weather were handled by individual offices at the U.S. Weather Bureau, and overseen by the Environmental Science Services Administration (ESSA). For example, from 1953 to 2004, the average number of yearly tornadoes was 908. The annual average of U.S. tornadoes, based on the most recent 10-year period from 2005 to 2014, is 1,201. If you look at a 20-year span of tornadoes reported from 1995 to 2014, the average is higher at 1,239. A 30-year period, from 1985 to 2014, accounts for an average of 1,141 tornadoes.

In a PowerPoint presentation shared with North Jersey Weather Observers in May 2011 and published on SlideShare titled Overview of U.S. Tornadoes, I provided some explanations accounting for the increase in the number of tornadoes reported since 1990. [It is outlined on slide 22.]

  • Population increase: More tornadoes are observed and reported.
  • Better technology: More tornadoes are detected by meteorologists.
  • Greater knowledge: Fewer tornadoes are mistaken for straight line wind damage; downbursts; and gustnadoes, short-lived whirling gust fronts.
  • Confirmation: Fewer tornadoes are double counted by separate eye witnesses, reporting the same twister.

There was also an increased effort to improve severe weather forecasting and to effectively communicate likely and imminent hazardous weather alerts to the public.  So in 1966, ESSA formed a specialized branch of the U.S. Weather Bureau to do just that. And it was given the name: National Severe Storms Forecast Center (NSSFC). Part of the scope of the NSSFC was to centralize and verify severe weather data from radar, and eye witness accounts (observed and videotaped) from storm chasers, the media and individuals. In 1970, the U.S. Weather Bureau changed its name to the National Weather Service (NWS), and the ESSA was rebranded as the National Oceanic and Atmospheric Administration (NOAA). Later that decade the roll out of Real-time operational forecasts and warnings, using Doppler radar, had become a game changer for the NSSFC. By the end of the 1980’s, the network of advanced Doppler radars, referred to as  NEXRAD (short for ‘Next Generation Weather Radar’), had significantly improved lead times in predicting severe weather events, including ice storms, tornadoes, and flash floods.  In 1995, the NSSFC was renamed the Storm Prediction Center. [For more history on SPC, go here.]

People living in the U.S. understand the destructive powers of tornadoes, especially in the Great Plains region and in Southeast states where many families have storm shelters and emergency kits for such events. Civil defense sirens, as part of the Emergency Alert System (EAS), are sounded in the vicinity of imminent danger when tornado warnings are issued, simultaneously with radio and TV broadcasts, and smartphone alerts. And schools have practice drills designed for tornado preparedness. It is also a significant advantage when a common language–English–is spoken in every state. According to U.S. Census Bureau data from 2011 almost 80% of U.S. residents, age 5 and older, spoke English “very well” or “well”. It is easier to communicate watches and warnings, and to inform the general public on the hazards and safety measures of tornadoes when one language is predominantly spoken. It also helps to reduce the risk of serious injuries and fatalities from tornadoes and other severe weather events with effective and timely alerts.

The researchers who published Tornadoes in Europe: An underestimated threat understand the need to educate the public on tornado preparedness; and the importance of advancing forecasting products and services. The analysis of the tornado data led them to outline the following conclusions:

  1. Increase awareness of the threat of tornadoes to Europe
  2. Encourage further discussion within and between different European countries to (a) improve monitoring and recording of tornado occurrence, (b) better understand the local environments associated with tornadoes, and (c) eventually lead to the development of forecasting and warning systems
  3. Stimulate the interest of the scientific community
  4. Influence decision-makers to develop tornado preparedness and response programs

In Europe, the logistics of consistent and proficient communication is considerably more challenging since multiple languages and dialects are spoken across 40 plus countries. Notwithstanding some hurdles, the annual number of confirmed and verified tornadoes has been steadily rising. This most likely reflects an increase in the general public’s awareness and due diligence in reporting tornadic activity. For example, despite a well under-reported yearly mean of 50 European tornadoes from 1953 to 2004, the annual average of tornadoes from 2005 to 2014 was 258.

In 2006, Europe confirmed and verified a maximum of 414 tornadoes. The U.S. tallied its most prodigious year of tornadoes in 2004 with 1,817. That is over four times the annual record of tornadoes reported in all of Europe. To put it in perspective: the greatest number of U.S. tornadoes in a single month occurred in April 2011 when 758 twisters left a devastating path of destruction throughout most of the Southeast and Mid-Atlantic states. This single month record in the U.S. is greater than a recent 3-year total of 747 tornadoes that touched down in Europe from 2013 to 2015.

april-2011-tornado-reports-map

Although the United States has greater than four times as many tornadoes, Europe has more than twice the number of people living in the continent (742 million) compared with the U.S. population (323 million). There are other factors aside from population density and the likelihood of a tornado touching down: the preparedness of those in harm’s way, the lead time to respond accordingly, the time of day when it hits, the strength (damage potential) of the twister, and the duration and trajectory of the path in relation to people and property.

Tornadoes spawn outside of Europe and the United States. Canada reports as many as 100 tornadoes a year. Australia has up to 25 twisters reported annually. Tornadoes touch down in other countries, but not as frequent. Provided is a table with tornado stats by continent with annual average, percentage, square miles, average frequency per 100,000 square mile, and notes on the concentration of activity. The ‘Tornadoes per Year’ takes into account under-reporting, esp. in Europe where Earth scientists and meteorologists have estimated it to be closer to an average of 300.

annual-tornado-stats-from-around-the-world

 

Here is a pie chart representing the percentage of tornadoes around the world.

percentage-of-tornadoes-around-the-world

 

And here is a bar chart illustrating the annual average of tornadoes.

annual-average-of-tornadoes-around-the-world

No matter how the data is visually presented, it is clear to see the significant disparity of tornadoes in the United States versus Europe and elsewhere. However, there are regions in every continent, except for Antarctica, that are susceptible to tornadoes. Atmospheric scientists cannot prevent tornadoes from forming. However, meteorologists have a crucial role in predicting these powerful twisters, and in working with local agencies and the media to notify the public when there is a likelihood and presence of severe weather. The United States has mastered the art and science of forecasting tornadoes with a high degree of accuracy, educating the public of its dangers, and issuing warnings in a fast and effective way. It is a blueprint of success for European weather scientists as they endeavor to 1) improve forecasting and to 2) raise public awareness. Eventually, tornadoes will no longer be considered “an underestimated threat” in Europe.

 

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Overview of U.S. Tornadoes

This presentation was put together in May 2011, following a very active stretch of severe weather, esp. in the Southeast region.