Hail is frozen precipitation in the form of balls or irregular clumps associated with thunderstorms. It is formed as small pieces of ice are held aloft by an updraft and grow by accretion as they collect supercooled water droplets. They can grow anywhere from the size of peas to softballs, and 3/4 inch is the severe criteria. Since a strong updraft is needed to support such weight, hail is typically produced by very strong thunderstorms. In fact, to support a grapefruit sized stone, a speed of approximately 100 mph is needed. Hail is a threat to life and property and has been responsible for millions of dollars worth of damage in North Carolina.

Below is a table relating qualitative descriptions of hail to actual diameter in inches.

Qualitative Description Diameter in Inches
Pea 0.25 to 0.5
Dime 0.7
Penny 0.75
Nickel 0.88
Quarter 1
Half Dollar 1.25
Walnut 1.5
Golf Ball 1.75
Hen Egg 2
Tennis Ball 2.5
Baseball 2.75
Tea Cup 3
Grapefruit 4
Softball 4.5

Photographs of various hail sizes compared to a ruler and other objects.

Hail Sizes Compared to Ruler Hail Sizes Compared to Other Objects

An analysis using Geographic Information Systems and data from the National Climatic Data Center's Storm Events Database was conducted to determine the distribution of hail events, damage, deaths, and fatalities across North Carolina from 1958 to 2004. The analysis reveals that hail events are most common in the southeastern part of the state, crop damage is concentrated in the eastern agricultural regions, and the threat to human life is small.

Below is a collection of maps summarizing North Carolina’s hail climatology.

Hail Events per County Property Damage from Hail per County Crop Damage from Hail per County Injuries from Hail per County Deaths from Hail per County

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