John Metcalfe was CityLab’s Bay Area bureau chief, covering climate change and the science of cities.
On this day in 2010, a town in South Dakota was visited by a two-pound ice monster from the sky.
Hail is responsible for up to $1 billion in damages a year. Surprised? Well, take a look at this hailstone. At eight inches across and nearly two pounds, this guy probably caused half that economic destruction for 2010 when it fell on July 23 of that year.
America's largest known hailstone dropped during a severe thunderstorm in Vivian, South Dakota, and was found by local man Les Scott. The National Weather Service has a sports-based system for measuring hail: There's golf ball-sized hail, as well as pool ball-, baseball-, and softball-sized. The ice monster Scott stumbled upon dwarfed all these punier balls, coming in volleyball-sized.
Scott lugged his discovery home and stuck it in the freezer, which subsequently suffered a 6-hour power outage that caused the stone to melt a bit. When the electricity came back on, the indomitable orb still measured 8 inches across with an 18.6-inch circumference. Officials at the weather service put the hailstone in front of a three-person committee (seriously), which deemed it both the widest and heaviest known in the land. (The heaviest stone ever weighed, though not measured, is still a pumpkin-sized 2.3-pounder that landed in Bangladesh in 1986.)
That the stone didn't land on anyone's noggin was fortunate, as hail can descend with enough force to crush the spine of a bull. Writes NOAA:
Small hail, up to about the size of a pea, can wipe out a field of ripening grain or tear a vegetable garden to shreds. Large hail, the size of a tennis ball or larger, can fall at speeds faster than 100 miles per hour and can batter rooftops, shatter windows and "total" automobiles.
This Vivian resident displays firsthand proof of the smashing power of major hailstorms, holding up a damaged section of roof after the foul weather passed: