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What Size Hail Causes Damage?

Posted by bobby flowers on Thu, Mar 22, 2012 @ 11:35 AM

What Size Hail Causes Damage?

Hail is a form of solid precipitation. It consists of balls or irregular lumps of ice, each of which is referred to as a hail stone. Unlike graupel, which is made of rime, and ice pellets, which are smaller and translucent, hail stones – on Earth – consist mostly of water ice and measure between 5 and 200 millimetres (0.20 and 7.9 in) in diameter. Hail is possible within most thunderstorms as it is produced by cumulonimbi (thunderclouds), and within 2 nautical miles (3.7 km) of the parent storm.

There are methods available to detect hail-producing thunderstorms using weather satellites and weather radar imagery. Hail stones generally fall at higher speeds as they grow in size, though complicating factors such as melting, friction with air, wind, and interaction with rain and other hail stones can slow their descent through Earth's atmosphere. Severe weather warnings are issued for hail when the stones reach a damaging size, as it can cause serious damage to man-made structures and, most commonly, farmers' crops.

 Although the diameter of hail is varied, in the United States, the average observation of damaging hail is between 2.5 cm (1 in) and golf ball-sized (1.75 in).

The US National Weather Service has a 2.5 cm (1 in) or greater in diameter threshold, effective January 2010, an increase over the previous threshold of ¾-inch hail. Other countries will have different thresholds according local sensitivity to hail; for instance grape growing areas could be adversely impacted by smaller hailstones.

The size of hail stones is best determined by measuring their diameter with a ruler. In the absence of a ruler, hail stone size is often visually estimated by comparing its size to that of known objects, such as coins. Below is a table of commonly used objects for this purpose. Note that using the objects such as hen's eggs, peas, and marbles for comparing hailstone sizes is often inaccurate, due to their varied dimensions.  



Hailstones ranging in size from Pea to Nickel

Common coin sizes


United States



0.705 inches (17.9 mm)[33]


Cent (or "Penny")

0.75 inches (19 mm)[34]


Five cents (Nickel)

0.88 inches (22 mm)[34]


Twenty-five cents (Quarter dollar)

1.00 inch (25 mm)[34]


Dollar (Loonie)

1.043 inches (26.5 mm)


50 Cents/Half Dollar

1.25 inches (32 mm)[34]



A large hailstone, approximately 13.3 cm (5 1/4 inches) in diameter, that fell in Harper, Kansas on May 14, 2004.

Other Objects




0.25 inches (6.4 mm)

Marble (small)

0.50 inches (13 mm)


0.50 inches (13 mm)

Grape (small)

0.62 inches (16 mm)

Olive (large)

0.75 inches (19 mm)

Shooter Marble

0.75 inches (19 mm)

Walnut/Ping-pong ball

1.50 inches (38 mm)

Ping-pong ball

1.60 inches (41 mm)

Squash ball

1.65 inches (42 mm)

Golf ball

1.75 inches (44 mm)

Hen egg

2.00 inches (51 mm)

Billiards (Pool) Ball

2.25 inches (57 mm)

Orange (Valencia/sweet)

2.38 inches (60 mm)

Tennis ball

2.50 inches (64 mm)


2.75 inches (70 mm)

Cricket ball

2.80 inches (71 mm)


3.00 inches (76 mm)


4.00 inches (102 mm)


4.50 inches (114 mm)

Melon (small)

4.75 inches (121 mm)

Computer CD

5.00 inches (127 mm)


6.50 inches (165 mm)

45 RPM Phonograph Record

7.00 inches (178 mm)


8.00 inches (203 mm)

Bowling Ball

8.25 inches (203 mm)


Hail can cause serious damage, notably to automobiles, aircraft, skylights, glass-roofed structures, livestock, and most commonly, farmers' crops.Hail damage to roofs often goes unnoticed until further structural damage is seen, such as leaks or cracks. It is hardest to recognize hail damage on shingled roofs and flat roofs, but all roofs have their own hail damage detection problems. Metal roofs are fairly resistant to hail damage, but may accumulate cosmetic damage in the form of dents and damaged coatings.

The largest hailstone in terms of diameter and weight ever recorded in the United States fell on July 23, 2010 in Vivian, South Dakota; it measured 8 inches (20 cm) in diameter and 18.62 inches (47.3 cm) in circumference, weighing in at 1.93 pounds (0.88 kg). This broke the previous record for diameter set by a hailstone 7 inches diameter and 18.75 inches circumference which fell in Aurora, Nebraska in the United States on June 22, 2003, as well as the record for weight, set by a hailstone of 1.67 pounds (0.76 kg) that fell in Coffeyville, Kansas in 1970.


While Hail Storms vary in all shapes and sizes Hail Damage can occur to your home and property. The size is typically between .75 and 1 inch in diameter that is consider damaging Hail. It is always a good practice to have your property inspected by a professional. We offer a free no obligation Hail Damage assessment at Orion Restoration. Please call today and have one of our trained specialist inspect your property. 1-866-816-ROOF.

Tags: Hail Damage, Hail Repair, Commercial Construction, Residintal Construction, Residential Construction, Roof Repair, Storm Damage, Hail Reapir, Insurace Claim, Emergency Response, Insurance Claim