A look at DC hail history after Sunday’s storms, from pennies to softballs

Pea to quarter-sized hail fell in Northwest D.C. on Sunday afternoon near the National Zoo for several minutes, coating roadways and damaging plants. (WTOP/Alejandro Alvarez)
Near the National Zoo in Northwest D.C., the ground was nearly coated with ice balls and the foliage they stripped from trees on their way down. (WTOP/Alejandro Alvarez) (WTOP/Alejandro Alvarez/Alejandro Alvarez)
Pea to quarter-sized hail fell in Northwest D.C. on Sunday afternoon near the National Zoo for several minutes, coating roadways and damaging plants. (WTOP/Alejandro Alvarez)
Pea to quarter-sized hail fell near the National Zoo for several minutes, coating roadways and damaging plants, especially small flower bushes. (WTOP/Alejandro Alvarez) (WTOP/Alejandro Alvarez/Alejandro Alvarez)
A radar scan of Sunday's storm on the Radarscope app. Each bulls-eye icon is a hail report submitted via the National Weather Service's public mPING program.
A radar scan of Sunday’s storm on the Radarscope app shortly after it moved east of the District. Each bulls-eye-like icon is a hail report from the public submitted to NOAA’s mPING program.
Quarter-sized hail is seen on MacArthur Boulevard near the Beltway on Sunday, June 2. (WTOP/Dave Dildine)
Quarter-sized hail is seen on MacArthur Boulevard near the Beltway on Sunday, June 2. (WTOP/Dave Dildine) (WTOP/Dave Dildine )
Pea to quarter-sized hail fell in Northwest D.C. on Sunday afternoon near the National Zoo for several minutes, coating roadways and damaging plants. (WTOP/Alejandro Alvarez)
Balls of ice, each approximately the size of a nickle, are seen near the National Zoo on Sunday afternoon. Hail in Northwest D.C. generally ranged from pea to quarter size, with isolated reports of golf ball sized pellets in the D.C. metro area. (WTOP/Alejandro Alvarez) (WTOP/Alejandro Alvarez/Alejandro Alvarez)
Quarter-sized hail is seen on MacArthur Boulevard near the Beltway on Sunday, June 2. (WTOP/Dave Dildine)
Quarter-sized hail is seen on MacArthur Boulevard near the Beltway on Sunday, June 2. (WTOP/Dave Dildine) (WTOP/Dave Dildine)
A lot of foliage was stripped off of trees by the half dollar sized hail along the C&O Canal hail on Sunday, June 2. (WTOP/Dave Dildine)
A lot of foliage was stripped off of trees by the half dollar sized hail along the C&O Canal hail on Sunday, June 2. (WTOP/Dave Dildine) (WTOP/Dave Dildine)
Pea to quarter-sized hail fell in Northwest D.C. on Sunday afternoon near the National Zoo for several minutes, coating roadways and damaging plants. (WTOP/Alejandro Alvarez)
Wilted and severed  flowers are seen in D.C.’s Woodley Park neighborhood on Sunday afternoon, damaged by a minutes-long hail storm. (WTOP/Alejandro Alvarez) (WTOP/Alejandro Alvarez/Alejandro Alvarez)
Pea to quarter-sized hail fell in Northwest D.C. on Sunday afternoon near the National Zoo for several minutes, coating roadways and damaging plants. (WTOP/Alejandro Alvarez)
A prolific coating of hail was evident for several hours after Sunday’s storm in Northwest D.C. despite summer-like heat — and on Monday morning, though the hail had long melted, torn leaves and small twigs remained as signs of a strong storm. (WTOP/Alejandro Alvarez) (WTOP/Alejandro Alvarez/Alejandro Alvarez)
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Pea to quarter-sized hail fell in Northwest D.C. on Sunday afternoon near the National Zoo for several minutes, coating roadways and damaging plants. (WTOP/Alejandro Alvarez)
Pea to quarter-sized hail fell in Northwest D.C. on Sunday afternoon near the National Zoo for several minutes, coating roadways and damaging plants. (WTOP/Alejandro Alvarez)
A radar scan of Sunday's storm on the Radarscope app. Each bulls-eye icon is a hail report submitted via the National Weather Service's public mPING program.
Quarter-sized hail is seen on MacArthur Boulevard near the Beltway on Sunday, June 2. (WTOP/Dave Dildine)
Pea to quarter-sized hail fell in Northwest D.C. on Sunday afternoon near the National Zoo for several minutes, coating roadways and damaging plants. (WTOP/Alejandro Alvarez)
Quarter-sized hail is seen on MacArthur Boulevard near the Beltway on Sunday, June 2. (WTOP/Dave Dildine)
A lot of foliage was stripped off of trees by the half dollar sized hail along the C&O Canal hail on Sunday, June 2. (WTOP/Dave Dildine)
Pea to quarter-sized hail fell in Northwest D.C. on Sunday afternoon near the National Zoo for several minutes, coating roadways and damaging plants. (WTOP/Alejandro Alvarez)
Pea to quarter-sized hail fell in Northwest D.C. on Sunday afternoon near the National Zoo for several minutes, coating roadways and damaging plants. (WTOP/Alejandro Alvarez)

Parts of the D.C. region received a rare dose of large and loud hailfall Sunday afternoon. Reports of ping pong ball and golf ball sized hail were received by the National Weather Service in a swath from Great Falls to Northwest Washington, and from Rockville to Aspen Hill, Maryland.

The last time golf ball sized hail fell in D.C. was on Capitol Hill in July 2016.

Photos posted on social media platforms showed hail stones bigger than quarters shredding leaves off trees and leaving dents in vehicles.

The National Weather Service uses hail size estimates from trained weather spotters to verify the issuance of their weather warnings. A severe thunderstorm warning was in effect for Montgomery County and the District of Columbia well in advance of the hailfall on Sunday afternoon.

By definition, a storm is considered severe if it produces hail stones of 1 inch in diameter or larger — roughly the diameter of a quarter.

The NWS revised its criteria for severe hail about a decade ago. Penny sized (0.75 inches) and nickel sized (0.88 inches) hail stones are nowadays considered sub-severe, as it typically causes minimal property damage.

Most hailfalls feature a mix of hail sizes, with the largest hail stones widely spaced out. The hail stones can be estimated by comparing them to familiar objects like coins, fruits and sports balls after the danger passes.


Video: WTOP/Alejandro Alvarez.

Most people are familiar with the general size of a golf ball, which could be why golf ball sized hail is so often reported. Hail records maintained by the National Climatic Data Center show a disproportionately high number of these 1.75-inch hail reports compared to 1.5 and 2-inch diameter hail reports.

The weather service, media and researchers prefer exact measurements from a ruler or calipers if possible.

Hail can become destructive when the balls of ice eclipse 2 inches in diameter. Hail of that magnitude will crack windshields and smash more fragile windows.

Tennis ball and baseball sized hail (2.5 inches and 2.75 inches, respectively) crashed into parts of Rockville and Waldorf, Maryland, on May 2, 2016. It was the largest hail ever recorded for Montgomery County. Significant vehicle damage occurred at car dealerships along Rockville Pike.

Hail larger than baseballs is exceptionally rare in the D.C. area, but there have been a few reports of giant balls of ice born from thunderheads in recent times.

On June 16, 2016, hockey puck sized hail measuring about 3 inches in diameter slammed into Bluemont, Virginia and Mount Weather. A year prior on June 23, 2015, hail up to the size of a regulation softball (about 4 inches) was reported north of Baltimore.

The largest hail on record in Maryland was unleashed by the same storm that produced the devastating La Plata tornado in April 2002. That supercell thunderstorm spewed hail stones up to the size of grapefruits, 4.5 inches in diameter, across a wide swath of southern Maryland, adding to property damage totaling upwards of $115 million.

The largest hail stone ever recorded in the U.S. was nearly as big as a volleyball. It plummeted to the ground in Vivian, South Dakota, on July 23, 2010. The massive hail stone was 8 inches in diameter and weighed about 2 pounds.

WTOP’s Dave Dildine previously worked as a researcher, mapping the distribution of hail storms.

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