A fierce storm over Argentina two years ago produced the world's largest hailstone, about the size of a football, scientists report.
Hail over the heavily populated city of Villa Carlos Paz, Province of Córdoba, Argentina in 2018 has probably broken the record for the largest hailstone, US researchers claim.
The largest stone in the storm measures up to 9.3 inches (23.6 cm) in diameter, which, if checked, would have broken the current world record of eight inches.
While the 9.3-inch stone has not been preserved and cannot be officially verified as a record breaker, investigators also report a 7.1-inch stone of the same storm.
The hail in the storm was so great that scientists proposed a new category to describe rocks larger than six inches – & # 39; gargantuan & # 39; hail.
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A gargantuan hailstone that fell in Argentina may have set a world record, according to investigators. This is one of three hailstones recorded during the storm over Villa Carlos Paz, named & # 39; Victoria & # 39; s & # 39; hail stone, measuring about 7.1 inches
Any hail stone more than six inches in diameter can cause serious physical damage to homes and cars, and can also knock someone unconscious with a direct blow to their head.
Researchers say that the public should be aware of how large these natural ice blocks can reach – not just in the US, which is famous for its hail.
& # 39; It's incredible – this is the extreme upper end of what you would expect from & # 39; e hail, & # 39; said Matthew Kumjian, associate professor at Penn State University in & # 39; e FS.
Such a well-observed case is an important step forward in understanding the environments and storms that produce gargantuan hail, and ultimately how to anticipate and detect such extreme events.
On February 8, 2018, a supercell storm produced gargantuan hail when it moved over the highly populated city of Villa Carlos Paz in Province of Córdoba, Argentina
& # 39; Anything greater than about a quarter of that in size can start putting dives in your car – in some rare cases, six-inch hail has actually gone through roofs and multiple floors in homes.
& # 39; We would like to help reduce the impact on life and property, to help anticipate these kinds of events. & # 39;
The hailstone fell during a supercell thunderstorm – the most violent type of storm characterized by persistent revolving updrafts – that in February 2018 ruined the Villa Carlos Paz city center.
The team interviewed local residents about their accounts of the storm, and discovered video and photos of social media that reveal the big hail in multiple locations.
Matthew R. Kumjian scans the 4.48-inch hail stone, one of & # 39; stones studied by the research team, using the 3D laser scanner, which offers & # 39; high-resolution maps of & # 39; a detailed form of & # 39; hail stone
Investigators are investigating the storm interviewed witnesses, visited sites where the damage occurred, collected photo data and analyzed radar observations.
In particular, the team looked at three notable hailstones observed by residents – a freezer-preserved 4.48-inch (11.38 cm) stone scanned with a 3D infrared laser scanner, a 7.1-inch (18-cm) stone and video of & # 39; giant 9.3-inch hailstone.
The 7.1-inch stone, called Victoria's stone, weighs 422g and probably sets the official record for hailstones found in the southern hemisphere.
Using the method of photogrammetry – taking measurements of photos – scientists estimate that the latest hailstone measures between 7.4 and 9.3 inches.
This would make the hailstone close as the world record maximum dimension – but it was not officially measured or preserved, and the estimate of its size comes from a photogrammetric analysis of a video posted on YouTube and social media and featured below.
The stone can be seen crashing into the road at about the 13-second mark.
Investigators searched the location that was seen in the video and measured reference projects that are evident in the frame, such as light wrist, widths of & # 39; green awning arms, sidewalk size and depth of sidewalk.
& # 39; We also place rulers in & # 39; a street at & # 39; the rushed impact location of & # 39; a hailstone, and took photos of & # 39; estimated location and vantage point of & # 39; a videographer, & # 39; reports the team in & # 39; Bulletin of the American Meteorological Society,
& # 39; This put us out of frame-by-frame photogrammetric analysis to determine the size of & # 39; to estimate a hailstone. & # 39;
A hailstone that fell near Vivian, South Dakota in July 2010 in the US, eight inches across, or about the size of a volleyball, holds the current record.
The National Oceanic and Atmospheric Administration, reporting on the Vivian hailstone in & # 39; time, said it was the largest in diameter and heaviest ever recorded in & # 39; e FS.
The Vivian stone itself moved the previous diameter hail record, which was 7 inches for a hail stone found in Aurora, Nebraska, in 2003.
Globally, there is a report of a hailstone in Bangladesh in 1986 that was recorded to have a mass of 1.02 kg – which is & # 39; probably the world record for mass & # 39 ;, Professor Kumjian said.
record-setting hailstone that fell in Vivian, South Dakota on July 23, 2010. The hailstone broke the United States records for largest hailstone by diameter (7.9 inches) and weight (1 pound) 15 ounces)
& # 39; D & # 39; there are unconfirmed reports of larger stones in terms of maximum dimension and mass from elsewhere, including China, but it is difficult to verify these, & # 39; he said.
Hail typically occurs during severe storms that produce strong, sustained updates.
Winds hold hailstones in the air long enough to grow to temperatures below zero high in & # 39; e atmosphere, but predicting & # 39; the size of & # 39; The stones remain challenging, scientists said.
Paper co-author Rachel Gutierrez found a connection between how fast a storm turns and larger hail size, but many remain unknown about the relationship.
The fact that a new giant hailstone has been reported from a storm outside the US is & # 39; invaluable & # 39 ;, she claims.
& # 39; There & # 39; s typically not much data from storms outside the US, & # 39; said Gutierrez.
& # 39; By showing this, we let these crazy, high-impact events happen around the world. & # 39;
The researchers say more volunteers are needed to report hail and help provide accurate measurements at the scene.
They can do this with a common item to scale, like a ruler, but even just video and photo that were posted on social media at a time is a valuable form of citizen science.
HAEL IS SOLID PRINCIPLES In the forms of ice balls
Hail forms in thunderstorm as drops of water are continually taken up and down, though the cloud is through updates and downslope.
When they go to the top of a cloud, it is very cold and freezes them.
Because the updates in thunderstorms are very large, they can hold these hailstones for a long time, so they get bigger and bigger by getting clad with more and more ice.
If the hailstones become really big, the updates in the cloud can no longer stop them and drop them to earth.
Today, they are big ice balls, and do not have time to melt before they reach the ground.
Hailstones are often spherical or conical in shape and most have a diameter smaller than an inch.
The largest hailstones often emerge as thin clouds collapse around & # 39; storms & # 39; to make multicell, which are just in US.
Source: Met Office
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