A huge hailstone found in northern Illinois in March has been confirmed the state's largest, adding to a record year for severe weather and tornadoes in America's hardest-hit state.

The hail's giant size

One hailstone from a severe thunderstorm in Kankakee, Illinois, on March 10, was measured by researchers to be up to 6.6 inches long.

That easily shattered the previous Illinois state record hail, a 4.75-inch long stone near Minooka on June 10, 2015, according to a report released Tuesday by NOAA.

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That's roughly the diameter of a standard 1-gallon paint can.

The stone weighed 1.228 pounds, slightly less than a standard NBA basketball.

These measurements were taken one week after the storm by scientists at Northern Illinois University and the Insurance Institute for Business & Home Safety using 3D laser scanning.

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A family in Kankakee saved the huge stone in their freezer, then reached out to NIU professor Victor Gensini, who later placed the stone in a portable freezer and moved it to NIU for storage.

An ad hoc State Climate Extremes Committee convened to investigate potential state weather records voted unanimously to accept this new Illinois state record for its length, and also recommend it for a state record weight and volume (about 38.7 cubic inches).

One prolific supercell

As you might imagine, it took one incredible severe thunderstorm to produce hail that huge.

Among other severe thunderstorms on March 10, one supercell storm tracked about 121 miles in 4.5 hours from central Illinois into northwest Indiana.

The most damaging part of the hail swath from Livingston into Kankakee Counties is shown in the map below.

That same supercell also spawned 12 tornadoes, including a half-mile wide EF3 tornado on the ground for almost 36 miles through parts of Kankakee and Aroma Park, Illinois.

(MORE: March 10 severe outbreak recap)

Tornado record, too

Illinois has already shattered its record for most tornadoes in any year, with 210 confirmed tornadoes as of the time this article was published.

It obliterated the previous yearly record, 142 from 2024, and is approaching the all-time record for any U.S. state, 244 in Texas.

It's also more than three times the state's average yearly tornado tally (66), according to NOAA's Storm Prediction Center.

Jonathan Erdman is a senior meteorologist at weather.com and has been covering national and international weather since 1996. Extreme and bizarre weather are his favorite topics. Reach out to him on Bluesky, X (formerly Twitter) and Facebook.