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

Tornado going over land close to a house.
Tornadoes tore up homes in New Orleans and its suburbs and were reported in communities from Texas to Mississippi and Alabama as severe storms swept across the South in late March 2022.
Conversation Media Group, the
Blue tarps cover damaged roofs in San Juan, Puerto Rico after Hurricane Maria in September 2017.
Study offers new framework for improving disaster science & community preparedness. Disasters such as hurricanes, wildfires, floods, tornadoes, and droughts are not only increasing, they are also striking the same place multiple times.
Cary Institute of Ecosystem Studies
The disasters just kept coming in 2021, from Hurricane Ida’s destruction across Louisiana and the Northeast to devastating wildfires in the West and damaging storms, tornadoes and floods.
Conversation Media Group, the
Better understanding of warning psychology will prevent disasters.
Psychology Today
Higher temperatures might create more favorable conditions for tornadoes but for now, scientists remain cautious about drawing a direct connection.
PhysOrg, Omicron Technology Ltd
A home heavily damaged by an F2 tornado that swept through Oregon, USA (2012)
Much of what we know about how a warming climate influences severe storms and tornadoes is regional, chiefly in the United States.
Conversation Media Group, the
Although their frequency may decrease, models suggest anthropogenic climate change will increase the intensity of tornado outbreaks.
Eos - AGU
Tornadic storms in the Southeast are often powered by an abundance of wind shear.
Conversation Media Group, the

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