Hail and Roof Damage

Although tornadoes and hurricanes tend to dominate news weather coverage, Mother Nature is also known to play hardball, throwing destructive and deadly hailstones down on us every year. According to the National Oceanic and Atmospheric Administration (NOAA), the United States witnessed over 6,962 hail storms in 2023. And, when hail hits, it can hit hard.

The largest recorded hailstone in the United States made land in Vivian, South Dakota in 2010. That stone weighed in at nearly two pounds, and was almost eight inches in diameter—just about the size of a bowling ball! While hail of this magnitude is highly unusual, hail of any size can damage lesser roofs. It wasn’t long ago that a hailstorm in Texas destroyed dozens of commercial and residential rooftops, with some hailstones even managing to rip through roofs, landing at the feet of the unsuspecting individuals inside.

So, until some mastermind learns to control the weather, how can we protect ourselves from the sometimes devastating effects of hail? By understanding it—and shielding ourselves from it.

Hailstones are clumps of layered ice that form when falling raindrops are carried skyward by thunderstorm updrafts. As they are carried upward, they reach extremely cold areas of the atmosphere (generally -10° C to -25° C) and, in the process, collide with other freezing raindrops. Eventually, a hailstone is formed, and it becomes too heavy for the updraft to sustain its high altitude. Gravity then takes over, and the hailstone falls back to the Earth, potentially damaging whatever lies below.

The size of hailstones, and the destruction they cause, typically depends on the strength and size of the updraft that carries them. Often, hailstones are fairly small. But, during intense thunderstorms, they can become behemoths.

Marble-sized hailstones typically fall to the Earth at around 20 mph, while baseball-sized hailstones can reach speeds of more than 100 mph. The amount of damage they cause can also be determined by their shape; while those that take on a smooth form can be damaging, it’s jagged hailstones that are the most destructive.

While hailstorms are most commonly associated with “Hail Alley,” the area consisting of Nebraska, Colorado, and Wyoming, hail can happen just about anywhere. In fact, it may surprise you to know that some of the most severe hail damage has happened outside these states. Here’s a look at 2017 hail damage estimates as reported by analytics firm Verisk, which provides data for insurance companies.

While determining where hail may strike can be a bit of a moving target, pinpointing when it may occur is a bit easier. Weather conditions that are ripe for hailstorm activity occur during the late spring, summer, and early fall months. So, May through September is “prime time” for hailstorms.