Hail is precipitation in the form of a chunk of ice that can fall from a cumulonimbus cloud. Usually associated with multicell, supercell and cold front induced squall line thunderstorms, most hail falls from the central region of a cloud in a severe storm.

Hail begins as tiny ice pellets that collide with water droplets. The optimum freezing level for the formation of hail is from 8,000 to 10,000 feet.

The water droplets attach themselves to the ice pellets and begin to freeze as strong updraft winds toss the pellets and droplets back up into the colder regions of the upper levels of the cloud. As the attached droplets freeze, the pellets become larger.

Both gravity and downdraft thunderstorm winds pull the pellets back down, where they encounter more droplets that attach and freeze as the pellets are thrown, once again, back up through the cloud.

 The more times a hailstone is tossed up and down through the cloud, the larger the hailstone will be. Hailstones the size of softballs had many more trips up and down through the cloud than pea-sized hailstones.

To create pea-size hail (about 1/2 inch in diameter) winds within the thunderstorm updraft will generally be around 20 miles per hour. Quarter size hail (3/4 of an inch in diameter) requires updrafts of about 40 miles per hour.

Golf ball size hail (1 3/4 inches in diameter) needs updrafts of around 55 miles per hour and softball size hail, approximately 100 miles per hour!

The largest hailstone ever measured in the United States fell at Coffeyville, Kansas, on September 3, 1970. It weighed 1.67 pounds and measured 17.5 inches in circumference.





 The two main types of damage caused by a hailstorm to your composition roof is granule loss, exposing the underlying mat, and rupturing the mat of the shingle. Loss of granules will shorten the life expectancy of the roof. Since the granules have been removed by the hail stones the matting is now exposed to the elements. The UV rays from the sun overtime can cause the mat to crack, adversely affecting the water shedding ability the roof previously had.

Rupturing of the mat is the more severe of the two types of hail damage. This is caused by larger hail stones impacting the shingle. When a shingle’s mat has been ruptured, the granules are gone and cracking or a hole is visual in places where the hail impacted the shingle. This greatly affects the shingles intended purpose of shedding water.

 Any time a shingle loses its water shedding ability, whether from granule loss or rupturing of the mat, water can start to deteriorate your roofing system.  Once the water reaches the roof fasteners, causing corrosion or the butted joints in the roof decking, water will be permitted to enter the building. 

You can seldom see roof damage, caused by hail, from the ground. Most people, not trained in the detection of hail damage, are unable to correctly identify hail damage even while on the roof.



Contact us for a Free Inspection Report of your roof.  One of our trained personal will come out and inspect your roof for any kind of damage.  You will then get a full-color report on the condition of your roof all for free!



Owens Corning






Oklahoma Roofing Contractors Association



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