This article is shared with permission from The Conversation, a site dedicated to sharing insights from experts in their fields.

In Johnson City, Texas, hailstones as large as grapefruits recently smashed car windows. In June 2024, a storm chaser encountered a near-pineapple-sized hailstone. Even bigger hailstones have been reported in states like South Dakota, Kansas, and Nebraska, causing extensive damage to aircraft and even penetrating residential roofs.

What causes hailstones to grow so large, and are hailstorms intensifying?

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As an expert in atmospheric science, I explore and instruct on extreme weather conditions and their dangers. Here is an explanation of how hail forms, the potential changes in hailstorms, and safety precautions to consider.

What Causes Hail to Grow So Large?

Hail starts as minuscule ice crystals caught in a thunderstorm’s updraft. These ice particles meet supercooled water—water that remains liquid below freezing temperatures—and freeze upon contact, causing the ice particle to enlarge.

As the hailstone ascends and descends within the storm, it encounters varying rates of supercooling, forming layers of ice that appear clear or cloudy. Cutting open a large hailstone reveals these strata, reminiscent of the rings inside a tree trunk.

The trajectory and duration of a hailstone’s journey through a thunderstorm cloud determine its potential size.

Supercell thunderstorms, which are rotating and long-lasting severe storms, often produce the largest hailstones. In such storms, hailstones can be held aloft in powerful updrafts, collecting more supercooled water for extended periods, until they become too heavy and fall, or drift from the updraft.

Hail is most prevalent in the spring and summer, driven by several factors: warm, moist air near the ground; an unstable atmosphere; varying wind speeds at different altitudes; and weather systems that trigger thunderstorms.

The Impact of Larger Hailstones

Hailstorms can wreak havoc, especially on agricultural lands where even small hail can devastate crops and bruise fruits.

As hailstones increase in size, their destructive power escalates dramatically. Hailstones the size of baseballs possess kinetic energy comparable to a major league fastball, amplifying the potential for damage to property such as roofs, siding, windows, and vehicles.

The financial toll from severe weather, heavily influenced by hail damage, has significantly increased over recent decades. This escalation is primarily due to growing populations in areas prone to hail and the rising costs of repairing or replacing damaged property.

Is Climate Change Exacerbating Hailstorms?

Many wonder if the uptick in hail damage is linked to climate change.

Research conducted by my colleagues and me over the past forty years on hail environments indicates that the conditions conducive to producing very large hail have become more frequent in parts of the central and eastern United States since 1979. Other studies examining storm formation factors and radar data on hail suggest slight increases in large hail, mainly over the northern Plains.

Several hypotheses suggest why climate change might be fostering conditions favorable for large hail. An increase in warm, moist air provides more energy for thunderstorms, enhancing the availability of supercooled water necessary for hail formation. Additionally, more unstable air masses originating from the elevated terrains of western North America are becoming common as earlier snowmelt speeds up land heating, which in turn warms the atmosphere more rapidly.

Climate change could also lead to less frequent small hail and more frequent large hail occurrences. As the atmosphere warms, the level at which water freezes rises, potentially allowing small hail to completely melt before hitting the ground. In contrast, larger hailstones, falling faster and requiring more time to melt, may be less affected by higher freezing levels.

Moreover, the combination of more conducive conditions for large hail and changes in the nature of hailstorms could result in an increase in very large hail events in the future.

Staying Safe During a Hailstorm

Experiencing a severe thunderstorm with large hail can be terrifying. Here are several safety tips for such situations:

• If you’re driving, find a safe place to pull over. Stay inside your vehicle. If you can spot a garage or a gas station awning nearby, drive there for cover.

• If you’re outdoors, seek refuge in a solid building. If caught in the open, protect your head.

• If you’re indoors, avoid windows and stay inside until the hail ceases.

Managing the aftermath of hail damage can be daunting, so it’s wise to prepare in advance. Understand what your home and auto insurance policies cover, be cautious of roofing scams post-hailstorm, and consider choosing building materials that are more resistant to hail damage.

This article was originally published on The Conversation. Read the original article.