Simply put, a hail storm is a type of weather event that occurs when large pellets of ice (also known as hail) fall from the sky. Yet, how exactly does a heavy material like ice make its way into the atmosphere, and more importantly, what kind of effect do large falling blocks of ice have on human populations?
As it turns out, hail can be dangerous and life-altering. While other weather phenomena often overshadow hail, it can be incredibly harmful — causing millions of dollars in damages to property, people, and landscape alike. Especially in the central United States, where hail storms most often occur, hail is a common, and consistently concerning phenomenon.
In general, precipitation encapsulates any type of weather that occurs as a result of water being evaporated up into the sky, condensed by the cold temperatures in the clouds and brought back down to earth by the pull of gravity. Hail is a special type of precipitation, that takes the form of pellets, or balls, of ice.
Hail is created when the water that is evaporated into the clouds becomes supercooled (below its normal freezing point of 0°C (32°F), but still a liquid). This supercooled water freezes as it comes into contact with other things, like raindrops or dust, allowing these frozen balls to grow bigger as they collide with more materials. Despite the weight of these ice pellets, updrafts keep the hail within the clouds. Finally, when the hail either becomes too large, or the updraft weakens, the hail is able to fall to the earth's surface. Hail can range anywhere from 5mm to 150mm in size — that means as small as a pencil eraser, or as large as a softball — and has been recorded falling at speeds of up to 90 miles (145km) per hour. To be considered a severe hail storm, hail must reach 1 inch in diameter (around the size of a bottle cap).
For a hail storm to form, warm weather, atmospheric instability, and wind all need to be present. These conditions are most often associated with thunderstorms and vertical cumulonimbus clouds. Subsequently, hail forms concurrently with most thunderstorms; however, in many instances, the hail is small, and melts before it reaches the earth's surface.
Because the only criteria necessary for hail storms to form include warm temperatures, and a cool atmosphere, hail storms can occur anywhere in the world. In the last year, large-scale hail storms were recorded in Southern Europe, Russia, China, and more.
Hails prevalence changes as weather patterns and temperatures change around the world; however, hail is most frequently found in the central United States. The region in which hail most often occurs has been nicknamed “Hail Alley”, and it stretches across the center of the United States — with Texas, Colorado, North Dakota, and Missouri serving as the anchoring walls of this area. “Hail Alley” experiences seven to nine severe hail events per year — far more than other areas of the country.
Hail is most likely to form in “Hail Alley” because of the high elevation of the region— which allows the freezing point in the atmosphere to exist closer to the ground. This means that in the central United States, hail can form in less intense storms, while in other parts of the country, it must be carried high into the atmosphere by large storms before it can occur. That being said, strong storms are still required for the creation of the catastrophic and gargantuan hail that causes most hail-related issues.
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Given the high speed, solid, and large nature of hail, it has unsurprisingly been recorded doing damage to people, property, and land alike. In total, large size scale hail costs the United States up to one billion dollars per year.
Fallen hail can destroy crops upon impact, breaking stalks and tearing leaves. This leaves the many agricultural communities of the region, without their primary source of livelihood.
Additionally, hail can do immense property damage. Vehicles are most susceptible to damage, as hail stones can easily break car windows or dent the sheet metal cars are made of. Furthermore, especially when accompanied by rough wind conditions, hail can destroy buildings — blowing shingles and facades clean off or puncturing holes right through a roof.
Lastly, the weight and force of the hail can be comparable to that of a MLB baseball pitch. Being pelted by numerous objects with the size and speed of a baseball can cause major injury for those caught in a hail storm.
Climate change will likely play a significant role in dictating the frequency and occurrence of hail storms in years to come. The warming temperatures associated with global climate change will encourage continued and greater levels of evaporation — the fuel for hail storms. Scientists also predict climate change will bolster upward winds in thunderstorms, allowing hail to continue crowing within clouds, before returning to earth’s surface.
While there are some caveats to consider — like the fact that moist air may help hail to melt before it reaches the planet's surface — hail has generally begun to be understood as an increasingly pressing issue in our world of extreme weather.
Hail storms are started through a very similar mechanism to tornados, subsequently, the storms are often seen in conjunction. On June 22nd and 23rd of 2023, areas across northwest Texas were struck by multiple tornadoes, hurricane-force winds, and softball-sized hail. The events killed four people and injured nine more. It also destroyed multiple homes, ruined crops, and scattered livestock across the area.
On June 21st of 2023, a large hail storm struck portions of the Denver area. Earlier in the day, the local weather service had warned of potentially golf-ball-sized hail, and winds that could propel the ice up to 50 miles per hour. Despite these warnings, a concert held at the open-air Red Rocks Amphitheater was set to go on. Before the concert began, concertgoers were notified of the extreme weather and told to take shelter. However, the outdoor nature of the venue made it difficult for many to find cover, resulting in around 100 injuries, and seven hospitalizations. Injuries consisted of severe bruising, cuts, and broken bones among several concertgoers. The outcome and management of this recent event raised questions about how we predict and consider hailstorms, and has begun a discussion about the seriousness of hail.
In order to avoid future situations like the red rocks hailstorm, several steps can be taken. First, infrastructure can be built to help protect against hailstorms. This includes installing shutters and building covers for vehicles and livestock. Additionally, when hail storms occur, it is important to move to an indoor area away from windows or glass.
Recent developments in weather forecasting data have made it much easier to detect hail from other, less dangerous, forms of precipitation. Hail has a much more unique size and shape than rain, snow, or sleet might have — this allows for a unique signature to be traced. These new forecasting developments help to assist public safety individuals to help warn when hail is coming and know when and where it will strike.
Hailstorms may not seem like a pressing weather phenomenon, however, in reality, these storms can do catastrophic damage. As catastrophe researcher Kelly Hereid stated, “Hail risk is a clear example of how a constant drumbeat of smaller events can produce losses that are on par with a big hazard like a hurricane.”