Geography of Hailstorms in the United States

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Hail is a weather phenomenon produced only during thunderstorms. Hail is ice that forms when rain is carried up into the atmosphere by thunderstorm updrafts. When the rain hits the colder levels of the atmosphere, it freezes and forms balls of ice that can range from pea-sized to the size of grapefruits. Gravity then pulls the ice balls down to the ground as precipitation.

What Areas of the United States Have the Most Hail?

While hail can form anywhere in the United States experiencing a thunderstorm, geography influences where hailstorms are more likely to occur. A study from 2012 found that the Great Plains area experiences the most hailstorms. A triangular region that extends from “southwest Texas, northeastward to northwest Missouri, then northwestward into western South Dakota, and finally down the Front Range of the Rocky Mountains, into eastern New Mexico and west Texas” is known as “Hail Alley”.

A secondary area of high hail activity can be found along the Eastern coast extending from eastern Pennsylvania through Florida. Within this area, the states of Georgia and South Carolina have the most prevalent hailstorms.

Map of annual hail days per year during 2007–10 in the United States. Source: Cintineo et al., 2012.
Map of annual hail days per year during 2007–10 in the United States. Source: Cintineo et al., 2012.

When do Most Hailstorms Happen?

Most hailstorms happen during the spring and summer months as heat and humidity build up, driving more severe thunderstorms.

What is the Largest Hail Recorded in the United States?

Hail can range in size from small, pea-sized hail to hail that can reach the size of a baseball, softball, or grapefruit. The largest-sized hail ever recorded fell in Vivian, South Dakota on June 23, 2010. The hailstone measured had a diameter of 8 inches, a circumference of 18.62 inches, and weighed 1 lb 15 oz.

Photo showing golf ball and baseball sized hail.
Comparative photo showing hail the size of golfballs and baseballs. Photo: OAR/ERL/Wave Propagation Laboratory, NOAA.

Satellite Imagery of a Supercell Thunderstorm in Texas

NOAA’s GOES East satellite captured the formation of a supercell thunderstorm in central Texas that produced hail the size of grapefruit.

Satellite imagery of a supercell thunderstorm on April 12, 2021 over central Texas.  Imagery: GOES-16, NOAA.
Satellite imagery of a supercell thunderstorm on April 12, 2021 over central Texas. Imagery: GOES-16, NOAA.

Video: Hailstorm Damage from 1997

Large-sized hail causes anywhere from millions of dollars to over a billion dollars worth of damage in the United States every year. On July 13, 1997, a hailstorm caused severe damage to the USGS EROS Center in southeastern South Dakota. This USGS video commemorated the event and the damage the hail caused.

References

Cintineo, J. L., Smith, T. M., Lakshmanan, V., Brooks, H. E., & Ortega, K. L. (2012). An objective high-resolution hail climatology of the contiguous United States. Weather and Forecasting27(5), 1235-1248. https://doi.org/10.1175/WAF-D-11-00151.1

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