Tornado

A tornado is a rotating column of air, extending from the base of a cumuliform cloud, and often visible as a condensation funnel in contact with the ground, and/or attendant circulating dust or debris at the ground (WMO, 2017).

The strength of a tornado can be estimated from the degree of damage caused using the Enhanced Fujita scale (Wind Science and Engineering Center, 2004; National Weather Service, no date).

Tornadoes kill fewer than 100 per year on average but they can be very destructive and cause huge economic losses. The United States is a major hotspot with about 1,000 tornadoes every year, causing 80 deaths and more than 1,500 injuries on average (National Geographic, 2019).

Owing to the unpredictable nature of tornados, protecting the public is focused on education and outreach which provide information on the tornado as a threat, how to identify a tornado and practical measures on how individuals can protect themselves, and how to find and watch warning systems that alert the public (CDC, 2020).

Since the advent of Doppler Radar, lead times for tornado warnings have increased from when a tornado first touches the ground to upwards of 14 to 20 minutes or more beforehand (WMO, 2017b; National Geographic, 2019).

Risk factors

  • Lack of early warning systems and preparedness programmes.
  • Even when warning systems are in place, the aged and children have higher mortality rates.
  • Populations living in mobile homes are at greater tornado risk. The rate of serious injury for mobile homes occupants is 85.1 per 1,000 compared to 3 per 1,000 for occupants in standard homes.

Vulnerable areas

  • The most tornado-prone areas in the world are in North America, in particular the Great Plains in the United States and south-central Canada.
  • Tornado Alley, a region that includes eastern South Dakota, Nebraska, Kansas, Oklahoma, northern Texas and eastern Colorado, is home to the most powerful and destructive of these storms.
  • The United States gets 75 per cent of all the world’s tornadoes, followed by Canada and Bangladesh.
  • Australia, New Zealand, South Africa, India, Argentina and the Russian Federation are also prone to strong tornadoes.
  • Communities living in poorly built houses close to potential flying objects are in particular danger. People outdoors when tornadoes occur are at higher risk of mortality.

The Enhanced Fujita Tornado Scale

The Fujita Scale is named for Dr TT (Ted) Fujita, who made the first systematic study of tornado forces; it was replaced by the Enhanced Fujita (EF) Scale in February 2007.

Risk reduction measures

  • Monitoring systems to observe thunderstorms with radar and receive reports on tornadoes.
  • A hazard map to identify risk and vulnerability.
  • A warning/communication system to alert people in the path of a tornado.
  • Underground shelters to protect people.
  • Avoiding mobile home settlements in risky zones.
  • Education and awareness about tornadoes, warnings and safe action.

Latest Tornado additions in the Knowledge Base

Update
According to National Weather Service data, 37 tornado warnings have been issued in Erdner’s area since 1986, and 27 of them occurred after 2010. Data on tornadoes in Pennsylvania dating back to the 1950s seems to show a slight increase.
Bulletin of the Atomic Scientists
Update
Waterspouts form over warm bodies of water (lakes as well as the ocean). Fair-weather waterspouts are thankfully more common and often form from cumulus clouds.
Conversation Media Group, the
Waterspout in waterbody
Update
Southern Italy has endured successive heatwaves this summer. Sea surface temperatures around Sicily on the day the Bayesian yacht sunk were reported to have been near 30°C. Warm ocean water is rocket fuel for storms that generate tornadic waterspouts
Conversation Media Group, the
Tornado in Colorado, USA
Update
Scientists take calculated risks when they’re storm chasing – enough to collect crucial data, but never putting their teams in too much danger. It turns out that driving is actually the most dangerous part of storm-chasing.
Conversation Media Group, the
Tornado, Iowa, April 2024
Update
Tornadoes are deadly, and part of the reason is due of the short warning times — on average 10 to 15 minutes., there is no time to evacuate. You must rely on the walls around you and the local building code could be the difference between life and death.
National Institute of Standards and Technology
Tornado going over land close to a house.
Update
The hyperactive season has been due to an abundance of two key ingredients for tornadoes: wind shear and instability.
Conversation Media Group, the
Cover
Documents and publications
Tornado risk, as determined by the occurrence of atmospheric conditions that support tornado incidence, has exhibited robust spatial trends in the United States Southern Plains and Mid-South during recent decades.
People in a destroyed house following Hurricane Matthew in Roche a Bateux, Haiti in October 2016
Update
UNICEF and the Civil Protection Department are distributing cash assistance to the 300 most vulnerable affected families, to ensure their recovery and that they do not sink into further poverty.
United Nations Children's Fund (Global Headquarters, New York)
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