Four dead and at least 35 injured as Iowa town hit by tornado.

Four people have been confirmed dead and at least 35 have been injured after a tornado hit the town of Greenfield in Adair County, Iowa, on Tuesday 21 May 2024. The tornado carved a 1.6 km path through the town, damaging or destroying 153 homes, including the the town's hospital, and leaving much of the town without power. Volunteers have come from across the State of Iowa to bring emergency supplies and help with the clean-up effort.

Damage caused by a tornado that hit the town of Greenfield in Iowa on Tuesday 21 May 2024. Cody Scanlan/Des Moines Register.

The tornado is estimated to have been a four on the enhance Fujita scale (or an EF-4 tornado); such a tornado will produce sustained windspeeds of 333–418 km per hour, potentially strong enough to damage even well-built structures, with frame homes completely destroyed and cars thrown like missiles. 

Tornadoes are formed by winds within large thunderstorms called super cells. Supercells are large masses of warm water-laden air formed by hot weather over the sea, when they encounter winds at high altitudes the air within them begins to rotate. The air pressure will drop within these zones of rotation, causing the air within them so rise, sucking the air beneath them up into the storm, this creates a zone of rotating rising air that appears to extend downwards as it grows; when it hits the ground it is called a tornado. 

Tornadoes can occur anywhere in the world, but are most common, and most severe, in the area of the American mid-west known as 'Tornado Ally', running from Texas to Minnesota, which is fuelled by moist air currents from over the warm enclosed waters of the Gulf of Mexico interacting with cool fast moving jet stream winds from the Rocky Mountains. Many climatologists are concerned that rising temperatures over the Gulf of Mexico will lead to more frequent and more severe tornado events.

Simplified diagram of the air currents that contribute to tornado formation in Tornado Alley. Dan Craggs/Wikimedia Commons/NOAA.

See also...

Fireball over the Iowa-Illinois border region.

Witnesses in the Midwestern United States have reported observing a bright fireball meteor slightly 6.30 am local time (slightly before 12.30 pm GMT) on Tuesday 28 November 2023. The fireball is described as having moved from northwest to southeast, entering the atmosphere to the west of Clinton and disappearing to the northwest of of Peoria. A fireball is defined as a meteor (shooting star) brighter than the planet Venus. These are typically caused by pieces of rock burning up in the atmosphere, but can be the result of man-made space-junk burning up on re-entry.

The 28 November 2023 Midwestern fireball, seen from Lead Hill, Arkasas. William Mattison/American Meteor Society.

Objects of this size probably enter the Earth's atmosphere several times a year, though unless they do so over populated areas they are unlikely to be noticed. They are officially described as fireballs if they produce a light brighter than the planet Venus. The brightness of a meteor is caused by friction with the Earth's atmosphere, which is typically far greater than that caused by simple falling, due to the initial trajectory of the object. Such objects typically eventually explode in an airburst called by the friction, causing them to vanish as an luminous object. However, this is not the end of the story as such explosions result in the production of a number of smaller objects, which fall to the ground under the influence of gravity (which does not cause the luminescence associated with friction-induced heating).

Heat map showing areas where sightings of the meteor were reported (warmer colours indicate more sightings), and the apparent path of the object (blue arrow). American Meteor Society.

These 'dark objects' do not continue along the path of the original bolide, but neither do they fall directly to the ground, but rather follow a course determined by the atmospheric currents (winds) through which the objects pass. Scientists are able to calculate potential trajectories for hypothetical dark objects derived from meteors using data from weather monitoring services.

See also...

Follow Sciency Thoughts on Facebook.

Follow Sciency Thoughts on Twitter.

Tornadoes kill at least eight in Mississippi and Arkasas.

At least seven people have died as a series of tornadoes swept across Mississippi on Sunday 12 April 2020, with another person having lost their life in a storm in Arkansas. The storms also hit Louisiana, where over 200 homes were destroyed, as well as Florida, Georgia, Texas, Alabama, Illinois, Wisconsin, and Iowa. As well as the obvious wind-damage the storms caused widespread flooding, and disruption to power distribution networks, with about 750 000 people across ten states losing electricity supplies.

The remains of a house in Monroe City, Louisiana, where between 200 and 300 homes were destroyed by a tornado on Sunday 12 April 2020. Monroe City/Facebook.

Tornadoes are formed by winds within large thunder storms called super cells. Supercells are large masses of warm water-laden air formed by hot weather over the sea, when they encounter winds at high altitudes the air within them begins to rotate. The air pressure will drop within these zones of rotation, causing the air within them so rise, sucking the air beneath them up into the storm, this creates a zone of rotating rising air that appears to extend downwards as it grows; when it hits the ground it is called a tornado. 

Tornadoes can occur anywhere in the world, but are most common, and most severe, in the area of the American mid-west known as 'Tornado Ally', running from Texas to Minnisota, which is fuelled by moist air currents from over the warm enclosed waters of the Gulf of Mexico interacting with cool fast moving jet stream winds from the Rocky Mountains. Many climatologists are concerned that rising temperatures over the Gulf of Mexico will lead to more frequent and more severe tornado events.

 Simplified diagram of the air currents that contribute to tornado formation in Tornado Alley. Dan Craggs/Wikimedia Commons/NOAA.

See also...

Follow Sciency Thoughts on Facebook.

Flash flood kills radio presenter in Des Moines, Iowa.

A man has died after his car was swept away during a flash flood caused by a thunderstorm in Des Moines, Iowa, on Saturday 30 June 2018. Radio sports commentator Larry Cotlar, 66, was one of three drivers whose vehicles were swept off roads by floodwaters during the storm, and was later found dead; the other two drivers were rescued safely. The incident happened as a series of thunder storms formed across Polk and Dallas counties, with over 250 mm of rain falling in under three hours in some places, resulting in a series of flash floods across the area, with one waters exceeding five metres in places, resulting in the flooding of many roads and buildings.

Flood waters in Urbandale in Polk County, Iowa, on Saturday 30 June 2018. Megan Salois/Twitter.

Thunderstorms are caused by heating of the land or water surface by the sun, causing air to expand, and thus rise, this causes more air to be drawn in to fill the gap, which is in turn heated and rises, repeating the process and creating a cycle. As the air rises it expands, and therefore cools, losing its capacity to retain water, leading to precipitation (rainfall), with higher levels of rainfall occurring when the initial air mass is warmer and more humid.

See also...

Follow Sciency Thoughts on Facebook.

Train derailment leads to major oil spill on the Little Rock River in Iowa.

Around 7300 barrels (870 000 litres) of crude oil have spilled into the Little Rock River near Doon in Lyon County, Iowa, on Friday 23 June 2018. Fourteen of the thirty two tanker trucks that came off the rails are thought to have been breached, releasing their oil into the river; about half of this is thought to have been contained by a seres of booms placed downstream of the derailment site, but the remainder has been lost into the river ecosystem.

Oil tankers in the Little Rock River in Iowa following a train derailment near Doon on 23 June 2018. Tim Hynds/Sioux City Journal/AP

The precise cause of the derailment is unclear, but it occurred after several days of heavy rain which had caused the Little Rock (and several other rivers in Iowa) to burst its banks, making it possible that the tracks had been undermined by flooding, or had had material dumped upon them which had caused the derailment.

Aerial photograph of the scene of the 23 June 2018 Iowa derailment. Sioux County Sheriff's Office/AP.

Trains carrying crude oil have become an increasingly important part of the distribution system in North America as both production of and demand for oil has exceeded the capacity of the pipeline network. There have been a number of incidents involving derailments and oil spills, and concerns about the safety of the trains following an incident in Lac-Megantic, Quebec, in July 2013,when a 72 car oil train derailed and exploded, killing 47 people.

See also...

Follow Sciency Thoughts on Facebook.

Iowa woman dies from West Nile Virus infection.

Health officials in Iowa have reported the death of a woman in the southwest of the state earlier this month. The woman has not yet been named, but has been described as being between 41 and 60 years of age. Iowa has recorded seven cases of the disease this year, with this being the first fatality; three other possible infections have been reported. In 2016 37 cases of infection with the Virus were reported in Iowa, with a single fatality.

West Nile Virus is a Mosquito-born Flavivirus (the group of RNA Viruses that also includes the Yellow Fever, Zika and Hepatitis C Viruses), first diagnosed in the West Nile District in Uganda in 1937, and subsequently reported in a number of African and Middle Eastern countries. The first case in the US was was reported in New York City in 1999, and it has subsequently been reported in every continental state of America. Outbreaks have also been reported in some European countries.

The West Nile Virus is a zoonotic infection, that principally infects Birds, and is transferred to Humans by Mosquitoes or occasionally Ticks. Infections have also been reported in a wide range of Mammal species, as well as in Crocodiles. Around 80% of infected Humans show no symptoms, with those who do generally suffering only a minor fever. However in a small number of cases the Virus infects the nervous system, causing a meningitis- or encephalitis-like infection that can often prove fatal. There is currently no known treatment for the Virus, making suppression and avoidance of Mosquitoes the best way to minimise fatalities from the disease.

Neural tissue infected by West Nile Virus. Brian Davies/University of Washington.

See also...

Follow Sciency Thoughts on Facebook.

Hundreds of homes damaged as storms sweep across America's Midwest.

Hundreds of homes have been destroyed an a number of people have been injured as series of storms swept across the American Midwest on Monday 6 March 2017. The worst of the damage occurred around Oak Grove on the border between Jackson and Lafayette counties in Missouri where about 500 homes and commercial buildings were damaged or destroyed by a tornado that reached three on the Enhanced Fujita scale (or an EF-3 tornado), with winds peaking at 245 km per hour. 

The aftermath of the 6 March 2017 Oak Grove tornado outbreak. Kansas City News and Weather.

Elsewhere in Missouri between fifty and sixty homes were damaged or destroyed by an EF-2 tornado with peak winds of over 210 kilometres per hour in Smithville. 46 homes were damaged in the Kansas City suburb of Leaward, while twelve aircraft hangers were damaged and one destroyed at Johnson County Executive Airport. Two people were injured and a number of properties were damaged after an EF-1 tornado with winds of 140-175 kilometres per hour hit Wentzville. A water treatment plant was damaged in Odessa and tornadoes were also reported in Lee's Summit and Macks Creek.

 Overtuned mobile home in Wentzville, Missouri following the 7 March 2017 tornado outbreak. Robert Cohen/St Louis Post-Dispatch.

In Iowa an EF-2 tornado with winds peaking at 185 kilometres per hour hit the city of Muscatine leaving a trail of destruction 200 m wide and over three kilometres in length, with three people injured and over eighty homes damaged. A second tornado hit the city of Blue Grass, though this caused only minor damage. Tornadoes were also reported in Minnesota, the earliest in the year ever reported in the state, as well as in Kansas and Illinois, while major thunderstorms were reported in Louisiana, Mississippi and Alabama.

 Damage in Seymour, Iowa, following the 7 March 2017 tornado outbreak. Daily Iowegian.

Tornadoes are formed by winds within large thunder storms called super cells. Supercells are large masses of warm water-laden air formed by hot weather over the sea, when they encounter winds at high altitudes the air within them begins to rotate. The air pressure will drop within these zones of rotation, causing the air within them so rise, sucking the air beneath them up into the storm, this creates a zone of rotating rising air that appears to extend downwards as it grows; when it hits the ground it is called a tornado. 

Tornadoes can occur anywhere in the world, but are most common, and most severe, in the area of the American mid-west known as 'Tornado Ally', running from Texas to Minnisota, which is fuelled by moist air currents from over the warm enclosed waters of the Gulf of Mexico interacting with cool fast moving jet stream winds from the Rocky Mountains. Many climatologists are concerned that rising temperatures over the Gulf of Mexico will lead to more frequent and more severe tornado events.

Simplified diagram of the air currents that contribute to tornado formation in Tornado Alley. Dan Craggs/Wikimedia Commons/NOAA.

See also...

Follow Sciency Thoughts on Facebook.