Part of a roof lays in front of a home, destroyed by a powerful tornado in Defiance, Missouri on Sunday, December 12, 2021. A tornado hit the small town west of St. Louis on Friday, December 10, 2021, destroying 25 homes and killing one.
Credit: © Bill Greenblatt, UPI/Alamy Images

Devastating tornadoes tore through Arkansas, Illinois, Kentucky, Mississippi, Missouri, and Tennessee on Friday, Dec. 10, 2021. At least 22 tornadoes were reported throughout the 6 states. The storm started with a powerful thunderstorm, which meteorologists believe generated the tornadoes. The largest of the tornadoes broke United States history as the longest tornado. From touch down to the point where the tornado picked back up, the tornado measured 227 miles (365 kilometers).

Most of the destruction occurred in western Kentucky. Although tornadoes can occur any time of the year, they are more common in spring and summer. Tornadoes rarely form in Kentucky in the month of December. In Mayfield, Kentucky, a tornado hit a candle factory where 110 people were working the night shift. The building collapsed in the storm. Reports show eight people from the factory were killed in the storm and six people are still missing. At least 64 people have been confirmed dead in Kentucky with more than 105 people still missing. Rescue efforts are still underway to locate missing people. On Sunday, President Joe Biden approved Kentucky’s request for assistance from the Federal Emergency Management Agency (FEMA).

More than a dozen people were killed from the storms in Illinois, Tennessee, Arkansas, and Missouri. The storms hit an Amazon warehouse in Illinois, killing six people. One tornado tore through a nursing home in Arkansas, killing one resident. Rescue workers and family members are still searching for missing people throughout the wreckage. Thousands of businesses, houses, and schools have been damaged. Across the affected states, more than 50,000 people have been without electricity since the storm Friday night. Rescue efforts have been complicated because many power lines and cell towers were damaged in the storms.

March 18, 2020

Earlier this month, on the night of March 2-3, massive thunderstorms spawned a cluster of tornadoes in Tennessee, killing 25 people and causing widespread destruction. The two most powerful tornadoes struck Nashville, the state capital, and nearby Putnam and Wilson counties. Tornadoes from the same storm system also touched the neighboring states of Alabama, Kentucky, and Missouri. Tennessee’s tornado outbreak was the worst since a group of more than 50 tornadoes killed 35 people in the state in April 2011.

Storm debris litters Putnam County, Tennessee, on March 4, 2020, a day after a tornado ravaged the area. credit: Brett Carlsen/Getty Images

Thunderstorms grew in size and intensity over Tennessee on March 2, and tornadoes were reported in eastern and northern parts of the state. Just after midnight, an EF3 strength twister hit downtown Nashville (in Davidson County) and quickly tracked eastward more than 60 miles (100 kilometers) into Wilson County. EF stands for the Enhanced Fujita scale, used to rate the strength of tornadoes. The scale rates tornadoes from 0, the weakest, to 5, the strongest. EF3 tornadoes have winds between 136 and 165 miles per hour (218 and 266 kilometers per hour) and can tear away roofs and walls from houses and overturn cars. An even stronger EF4 tornado—with winds up to 200 miles per hour (322 kilometers per hour)—then hit nearby Putnam County, but spared most of Cookeville, the county’s largest town. Of the 25 deaths from the Tennessee tornadoes, 18 of them occurred in Putnam County. Hundreds of people were injured in the storms, and numerous buildings were destroyed.

Tornadoes struck Nashville and nearby ares of central Tennessee on the night of March 2-3, 2020. credit: World Book map

In the days after the storms, Tennessee Governor Bill Lee declared a state of emergency, and the Federal Emergency Management Agency (FEMA) provided millions of dollars in assistance to the hardest-hit areas. Schools, public offices, and interstate highways were closed for days in the region, and tens of thousands of people were without electric power.

December 1, 2016

Emergency medical services personnel in Melbourne, Australia, dealt with an unprecedented number of calls last week from people suffering respiratory symptoms as a freak weather event known as “thunderstorm asthma” swept the city. Doctors are still treating dozens of patients for a variety of serious respiratory conditions, and at least eight people have died. Meanwhile, scientists are trying to understand how this rare and little-understood event occurred.

Clouds gather over Melbourne, Australia, where recent thunderstorms have caused fatal asthma attacks. Credit: © Sunflowerey/Shutterstock

Asthma is a lung condition characterized by breathlessness, wheezing, and coughing. People with asthma suffer from inflammation of the bronchi (airways to the lungs). The inflamed airways react to irritation by swelling and constricting. These changes obstruct airflow (the ability to force air in and out of the lungs). A person may feel short of breath or have difficulty breathing. Severe attacks may involve spasms (sudden constriction) of the airways. Sufferers gasp for air and feel that they are suffocating. These attacks require immediate medical attention and can cause death.

A variety of environmental conditions, called triggers, may irritate the sensitive airways of people and cause an asthma attack. Triggers include pollen, mold spores, chemical irritants, tobacco smoke, animal dandruff, and dust mites. The term thunderstorm asthma refers to rare weather events where large storms generate powerful winds that churn up pollen and dust into the air. Recent hot, dry weather around Melbourne led to large ryegrass pollen deposits in the region. Once this pollen was in the air, thunderstorm winds ruptured the pollen grains into even smaller particles. These particles were small enough to be inhaled deep into people’s lungs, causing irritation and acute asthma attacks.

The last recorded outbreak of thunderstorm asthma in Australia was in 2010. That event was not nearly as severe as the one that occurred last week. Scientists worry that such unusual weather events will become more frequent and more deadly in Australia because of climate change.

July 23, 2012

A torrential 10-hour downpour on July 21 and 22 in Beijing left 77 people dead. According to local meteorologists, the storm was the greatest single deluge in Beijing since record keeping was begun in 1951. Approximately 6.7 inches (17 centimeters) of rain fell in some parts of the Chinese capital, and as much as 18 inches (45.7 centimeters) fell in some suburban districts. Floodwater in some streets rose to as high as 20 feet (6 meters). Flooding at electric power generating plants led to blackouts in parts of the city. Fierce thunderstorms forced the cancellation of 500 flights at Beijing International Airport, stranding some 80,000 passengers overnight.

Downtown Beijing has many modern skyscrapers, hotels, shopping centers, and office buildings. Some structures in the city, such as the pavilion in the foreground, feature elements of traditional Chinese architecture. (© Art Directors)

The number of deaths and the widespread destruction triggered criticism of the poor quality of the city’s infrastructure and of the government’s feeble response to natural disasters. Despite the billions of dollars spent to upgrade Beijing’s infrastructure, rainwater quickly overwhelmed the city’s sewage system. One Beijing newspaper published an article stating that the downpour “exposes holes in the modernization drive. . . . In recent years, floods caused by rain storms have repeatedly occurred in Chinese cities. And the latest downpour in Beijing has stirred up a new round of skepticism on the quality of infrastructure amid rapid urbanization.” Another newspaper openly criticized the government for not deploying an emergency broadcast system, not setting up special emergency hotlines, and not opening government shelters.

July 2, 2012

Some 3 million residents in the mid-Atlantic region of the United States were left without electric power after a series of extremely violent storms downed hundreds of trees and power lines late on June 29. At least 17 people were killed, most of them by falling trees. The National Weather Service described the storm system as a derecho, a fast-moving band that can produce hurricane-force winds. The crescent of storms swept down from Indiana and Ohio, across the Appalachians, and into the mid-Atlantic states, causing particually widespread damage in Virginia, the District of Columbia, and Maryland.

On June 29, a huge region of the United States from the Midwest to the Southeast had record-setting high temperatures: 104 °F (40 °C) in Raleigh, North Carolina, and Washington, D.C.; and 109 °F (42.7 °C) in Nashville, Tennessee, and Columbia, South, Carolina. The 104 °F temperature was the hottest June day in the nation’s capital in 142 years of record keeping.

A derecho is a widespread, long-lived windstorm associated with a line of thunderstorms. A derecho can sometimes last for more than a day and blow across a distance of several hundred miles. (© Jim Reed, Corbis)

As the hot air rose, it clashed with a cold front, giving birth to violent thunderstorms. Fueled by the heat and powered by roaring upper level winds, the storms grew in intensity as they moved southeast. Winds of 72 miles (115 kilometers) per hour were clocked in Fredericksburg, Virginia, and 80 miles (128 kilometers) per hour in Ft. Wayne, Indiana. Meteorologists believe that this derecho is likely to go down as one of the worst on record along its entire path, from northwest Indiana to the Jersey shore. Derechos are most common in the Midwest and Great Lakes region between May and July.

Additional World Book articles:

• Weather
• The Forecast: Better Weather Prediction Ahead (a special report)

April 16, 2012

A series of powerful thunderstorms spawned more than 120 tornadoes across the Plains states during a 24-hour period on April 14 and 15. The tornadoes were part of a weather system that crossed parts of Oklahoma, Kansas, Nebraska and Iowa. The National Weather Service confirmed that Kansas alone had 99 tornadoes on the night of April 14. In Oklahoma, at least 6 people were killed and 28 others injured in Woodward, a town 140 miles (224 kilometers) northwest of Oklahoma City. A tornado caused widespread damage in Wichita, Kansas, including the loss of electric power in parts of the city. Between 75 to 90 percent of the homes in Thurman, Iowa, were leveled, but miraculously, there were no major injuries. Outside the town, five tractor-trailers traveling on Interstate 29 were overturned by the high winds.  A tornado took the roof off the regional hospital in Creston, Iowa, a town of 7,800 people about 75 miles (120 kilometers) southwest of Des Moines.

Although the tornado season has just started in the United States, meteorologists point out that there have already been dozens of destructive twisters from Illinois to Texas. Tornadoes have killed at least 40 people in the United States so far in 2012.

A tornado's winds can swirl at speeds of hundreds of miles or kilometers per hour, hurling debris in all directions. Copyright Gene & Karen Rhoden, Peter Arnold Images/photolibrary

Additional World Book articles:

• Safety (During a tornado)
• Storm
• Fire From the Sky (a special report)
• The Forecast: Better Weather Prediction Ahead (a special report)

April 10, 2012

March 2012 was the warmest March in the United States since record keeping began in 1895, the National Oceanic and Atmospheric Administration (NOAA) announced on April 9. The first quarter of 2012–January, February, and March–was the warmest ever recorded in the continental United States (not including Alaska and Hawaii). The average temperature was 42 °F (5.5 °C), 6 degrees Fahrenheit above the long-term average. The warm temperatures contributed to conditions favorable for severe thunderstorms and tornadoes. According to NOAA’s Storm Prediction Center, more than 220 tornadoes were reported in the United States in March.

A resident surveys the wreckage of a house blown off its foundation by a tornado. Most tornado damage is severe but localized. (AP Photo)

On March 2, for example, deadly storms blew across the Midwest and South, spawning dozens of tornadoes that left 40 people dead amid the rubble of destroyed buildings and overturned vehicles. The storms touched down in 9 states, killing 21 people in Kentucky, 13 in Indiana, 4 in Ohio, and 1 each in Alabama and Georgia. According to the National Weather Service, the four tornadoes that hit Kentucky with winds of up to 160 miles (358 kilometers) per hour were the worst in the region in 24 years. In Indiana, an EF-4 tornado–the second highest rating on the Enhanced Fujita  scale–slammed Henryville with winds of 175 miles (280 kilometers) per hour, then mowed over southeastern Indiana for more than 50 miles (80 kilometers). The March 2 storms resulted in the first billion-dollar disaster of 2012.

Additional World Book articles:

• Global warming
• Weather

April 4, 2012

Rare twin supercells unleashed at least 18 tornadoes on the Dallas-Forth Worth metropolitan region. (A supercell is a massive low-pressure center characterized by a very large cumulonimbus cloud and long-lasting thunderstorm, often producing numerous and violent tornadoes.) The National Weather Service characterized the storms as among the most destructive in the area’s history. Twisters flung several massive semi-tractor trailers into the air and tossed a school bus across a road and into a diner. Hundreds of houses were severely damaged or leveled in the Dallas suburbs of Arlington, Lancaster, and Forney. In Arlington, an entire wing of a nursing home collapsed, forcing the evacuation of dozens of residents. The storms left thousands of households without electric power. Miraculously, there were no fatalities and relatively few injuries.

A supercell thunderstorm is a violent storm dominated by a single gigantic cell--a weather system made up of storm clouds and the winds associated with them. Rain and hail may fall for hours. (National Center for Atmospheric Research/University Corporation for Atmospheric Research/National Science Foundation)

At the Dallas-Ft. Worth International Airport, all flights were canceled, stranding thousands of passengers. Baseball-size hail pounded planes on the tarmac waiting for take-off. “The noise of ice . . . hitting the aluminum exterior of a 757 was as deafening as it was frightening,” noted one passenger.

Although the tornado season has just started in the United States, meteorologists point out that there have already been dozens of destructive twisters from Illinois to Texas.

Additional World Book articles:

• Safety (During a tornado)
• Storm