Hail is one of the more underrated hazards in a severe thunderstorm, and the stones falling from the most intense storms have been trending toward the large end of the scale. Once dismissed as an occasional summer nuisance, hail the size of a golf ball, a baseball, or even a softball is showing up in national reports more frequently, and meteorologists studying the trend want to know whether the jump reflects genuinely stronger storms, better reporting, or some mix of both.
How Hail Gets Measured, From Pea to Softball
Forecasters size hail by comparing it to familiar round objects, a scale the National Severe Storms Laboratory uses to standardize public reports: pea-size hail runs about a quarter of an inch across, quarter-size marks the threshold for an official severe-thunderstorm warning at one inch, golf-ball-size reaches 1.75 inches, baseball-size hits 2.75 inches, and softball-size tops out around 4.5 inches. Anything larger than that is rare enough that it tends to make news on its own, both for the physical damage it can do to roofs and vehicles and for what it says about the storm that produced it.
The Record-Setting Stones on the Books
The largest hailstone ever recovered in the United States fell near Vivian, South Dakota, on July 23, 2010: eight inches across and just under two pounds, a record that still stands. More recent extremes have set new marks at the state level rather than the national one. Texas recorded a 6.4-inch stone on April 28, 2021, and Colorado’s state record fell on August 8, 2023, at 5.25 inches. Each of those events required a storm violent enough to keep a stone suspended in its updraft long enough to grow to that size before gravity finally won.
Why Size Is Not the Only Thing That Matters
Hail does not need to reach softball size to be expensive. Even hail in the quarter-size-to-golf-ball range can add up to significant losses once it is spread across a metropolitan area full of roofs, vehicles, and siding, which is why insurers already count hail among the costliest categories of severe-weather damage in the country before any trend toward larger stones is even factored in. Agricultural losses follow a similar pattern: a single hail-producing storm can shred a season’s worth of corn, soybeans, or fruit in minutes across a wide swath of farmland, damage that is often handled through separate crop-insurance programs rather than standard property coverage. That underlying cost is part of why the shift toward more frequent large-hail reports, not just the occasional record-setting stone, is drawing sustained attention from insurers and agricultural economists alike.
Why Stronger Storms Make Bigger Hail
A hailstone grows in layers as it cycles through a thunderstorm’s updraft, picking up supercooled water that freezes onto its surface each time the stone passes back through the coldest part of the cloud. The longer and more violently that updraft can hold a stone aloft, the more layers it can add before it becomes too heavy to stay suspended and falls to the ground. Because updraft strength scales with a storm’s overall intensity, the biggest hailstones, including the golf-ball, baseball, and softball-size stones that make headlines, are essentially proof of an unusually powerful storm rather than an ordinary one, a relationship hail researchers use to help forecast which storms are likely to produce damaging stones.
A Recent Surge in Large-Hail Reports
The trend line has moved sharply in recent years. June 2023 brought 540 reports of hail two inches or larger across the country, and July 2023 added 305 more, both new monthly records that beat the previous highs by more than 200 percent, and 2023 and 2024 each went on to set new annual records for two-inch-or-larger hail reports, with the largest stones in those reports reaching baseball and softball size in multiple states. Meteorologists examining the increase have been careful to note that better storm-spotting networks and denser population in hail-prone areas explain part of the rise in reports, separate from any change in how large individual stones are actually growing.
What’s Driving the Increase
Untangling how much of the trend comes from a changing atmosphere versus more people simply being in position to see and report hail is now an active area of research. Scientists are working to separate the role of a warming atmosphere, which can feed more energy into severe storms, from the role of population growth spreading into places that always produced large hail but previously had few observers around to record it. The physical mechanics of hail formation have not changed, but the conditions that let a storm sustain the kind of updraft needed to grow a baseball- or softball-size stone appear to be occurring on a more frequent basis, which is why hail research remains one of the more closely watched corners of severe-weather science.
This article was produced with the assistance of AI and reviewed by Morning Overview editors.
More from Morning Overview
