This article explains how NOAA’s State Climate Extremes Committee confirmed the Virgo Park hailstone as the largest hailstone ever recorded in Texas, with a diameter of 7.1 inches.
Found during a June 2, 2024 severe storm in the Texas Panhandle, the stone underscores the extreme end of hail formation and the challenges of measuring colossal hail from photos and eyewitness reports.
The careful verification process used by scientists and meteorologists to certify records is also highlighted.
Record hail in Texas: Virgo Park hailstone
The Virgo Park hailstone stands as Texas’ largest hailstone on record, surpassing the previous Texas mark of 6.5 inches.
Its discovery during a robust tornadic supercell on June 2, 2024, points to an environment highly favorable for very large hail.
While the U.S. record remains 8 inches, set in Vivian, South Dakota, in 2010, the Texas value still represents a remarkable regional extreme that captured national attention.
Two key factors shaped the verification story: the circumstances of the find and the method used to size the stone without a direct measurement.
The hailstone was unearthed from a roadside ditch by storm tracker Val Castor, who initially mistook it for a discarded gallon of milk.
Photographs he shared with the National Weather Service and the Insurance Institute for Business and Home Safety provided the data that would be analyzed for certification.
How scientists verified the size
Because no one was able to place the hailstone on a ruler or caliper in the field, SCEC relied on a blend of measurements from multiple sources to determine a diameter.
Castor’s estimate placed the stone around 7.25 inches, while advanced analyses conducted by IBHS produced two measurements: an AI-based estimate of 7.06 inches and a photogrammetry measurement of 7.16 inches.
In a cautious, scientifically rigorous step, the committee elected to use the most conservative figure for certification: 7.10 inches, and the vote to certify the diameter was unanimous.
- The hail originated from a tornadic supercell that had already produced softball-sized hail in very favorable atmospheric conditions for extreme hail growth.
- Direct physical measurement was not possible in the field, so researchers depended on photographic evidence and independent analyses.
- The combination of eyewitness reports, images, and multiple analytical methods helped establish a defensible diameter under NOAA’s standards.
Context and implications for science, safety, and policy
The Virgo Park hailstone illustrates not only the raw power of severe storms but also the practical limits of field measurements.
By using a blend of AI-based calculations, photogrammetry, and conservative judgment, scientists can produce credible records that inform forecasts, risk assessments, and engineering standards.
For the insurance industry and building safety researchers, such data points refine models for hail damage risk and inform design criteria for hail resistance in vulnerable structures.
Although 7.10 inches is record-setting for Texas, the national benchmark remains higher—8 inches—set in 2010.
This distinction underscores the regional variability of extreme hail, as well as the ongoing need for robust observational networks and standardized verification practices.
Looking ahead: lessons for forecasting and public awareness
Events like the Virgo Park hailstone emphasize the importance of rapid documentation and transparent reporting.
As forecasting methods improve and remote sensing technologies advance, scientists expect to tighten the timeline between an extreme storm event and its formal verification.
Here is the source article for this story: Experts confirm this hailstone broke the record as the biggest in Texas history