What Is Hail? Hail 101

Understanding the Frozen Menace Falling from Texas Skies

What is hail? Hail is frozen precipitation consisting of solid ice balls or lumps that form inside powerful thunderstorms and can range from pea-sized pellets to grapefruit-sized chunks weighing over a pound.

Quick Facts About Hail:

• Minimum Size: Must be at least 0.2 inches in diameter to be classified as hail
• Severe Threshold: 1 inch diameter or larger (quarter-sized) is considered severe by the National Weather Service
• Fall Speed: Small hail falls at 9-25 mph, while large hail (2-4 inches) falls at 44-72 mph
• Formation: Requires strong thunderstorm updrafts and supercooled water droplets high in cumulonimbus clouds
• Damage Potential: Can destroy roofs, vehicles, crops, and even cause injuries or death

Unlike snow, which forms from water vapor turning directly to ice, or sleet, which freezes as it falls, hail grows by collecting layers of supercooled water as it’s repeatedly carried up and down within a thunderstorm’s powerful updrafts. These updrafts can reach speeds of 110 mph, suspending hailstones in the cloud for up to 30 minutes as they accumulate ice and grow larger.

For Texas property owners, hail is a serious threat. In 2022 alone, Texas experienced 458 major hail events. The state routinely leads the nation in hail frequency, with an estimated 1.6 million properties damaged in 2021, resulting in $5.1 billion in claims. The largest hailstone in Texas history fell near Hondo in April 2021, measuring 6.4 inches in diameter—larger than a softball.

I’m Ryan Majewski, General Manager of Certified Water & Fire Restoration, where I’ve spent over a decade helping Texas homeowners and businesses recover from storm damage, including the devastating effects of hailstorms. Understanding what is hail and how it forms is the first step in protecting your property and knowing when to call for professional restoration services.

What is Hail? The Science Behind the Ice

When we talk about what is hail, we’re referring to a fascinating meteorological phenomenon that, while beautiful from afar, can be incredibly destructive up close. It’s a form of solid precipitation, distinct from other frozen forms like snow or sleet, primarily due to its formation process and size. Hailstones are essentially balls or irregular lumps of ice.

The journey of a hailstone begins in powerful cumulonimbus clouds, the towering giants that bring us severe thunderstorms. Inside these clouds, strong currents of air, known as updrafts, play a crucial role. These updrafts carry raindrops far upward into extremely cold regions of the atmosphere. Here, these water droplets often remain liquid even below their freezing point, a state we call “supercooled water.”

These supercooled droplets then encounter tiny ice crystals or graupel (soft ice pellets), which act as “hail embryos.” As these embryos are tossed around within the cloud, they collide with more supercooled water droplets, which instantly freeze onto their surface. This process, called accretion, causes the hailstone to grow.

A unique characteristic of many hailstones is their layered structure, often resembling an onion. These layers can alternate between clear ice and opaque ice. Clear ice forms when the supercooled water freezes slowly, allowing any trapped air bubbles to escape. Opaque ice, on the other hand, forms when the water freezes rapidly, trapping air bubbles and giving it a cloudy appearance. This layering tells a story of the hailstone’s tumultuous journey through different temperature and liquid water content zones within the thunderstorm.

How Hail Forms Inside a Thunderstorm

The formation of hail is a delicate dance between powerful atmospheric forces. For a hailstone to grow to a significant size, several atmospheric conditions must align perfectly.

First and foremost, we need strong updrafts within the thunderstorm. These vertical winds are like elevators, lifting the developing hailstones repeatedly into the cloud’s colder upper reaches. The stronger the updraft, the longer a hailstone can remain suspended and continue to grow. Updrafts in severe thunderstorms can reach speeds exceeding 110 mph, which is why hailstones can sometimes stay in the cloud for up to 30 minutes, accumulating layer after layer of ice.

The freezing level, the altitude at which air temperature drops to 32°F (0°C), must also be relatively low. This ensures that the supercooled water region, where hail primarily grows, is extensive. Water droplets freeze onto the hailstone, and as it gets heavier, gravity tries to pull it down. However, if the updraft is strong enough, the hailstone is lifted again, collecting more moisture and growing larger. This cycle continues until the hailstone becomes too heavy for the updraft to support, or the updraft weakens, and then it falls to the ground.

Hailstones don’t grow by simply being lofted to the very top of the thunderstorm. At extremely high altitudes, temperatures drop below -40°F, where all water is already frozen. Hailstones require liquid water to grow, meaning they typically grow in the mid-to-upper levels of the storm where supercooled liquid water is abundant.

To dig deeper into the fascinating mechanics of hail formation, you can explore the Scientific research on hail formation conducted by experts in the field.

Hail vs. Sleet, Snow, and Graupel: A Clear Comparison

While all are forms of frozen precipitation, understanding what is hail truly means differentiating it from its icy cousins. The primary differences lie in their formation processes, characteristics, and the atmospheric conditions that produce them.

Here’s a breakdown:

Feature	Hail	Sleet (Ice Pellets)	Snow	Graupel (Soft Hail/Snow Pellets)
Definition	Lumps/balls of ice, >0.2 inches	Small, translucent ice pellets, <0.2 inches	Aggregates of ice crystals (snowflakes)	Opaque, soft, fragile ice pellets, <0.2 inches
Formation	Forms in strong thunderstorm updrafts; repeated cycles of freezing supercooled water	Rain melts in warm layer, then refreezes in deep cold layer near surface	Water vapor deposits directly as ice crystals in cold clouds	Supercooled water freezes onto snow crystals (riming)
Cloud Type	Cumulonimbus (thunderstorms)	Stratiform clouds (winter storms)	Stratiform clouds (winter storms)	Cumuliform or stratiform clouds
Temperature	Requires strong updrafts and freezing/supercooled layers high in atmosphere	Requires an inversion: warm layer above freezing layer near surface	Requires entire atmospheric column to be below freezing	Occurs when supercooled water droplets are present in cold clouds
Particle Size	0.2 inches to over 8 inches	Generally <0.2 inches	Varies greatly, often aggregates	Generally <0.2 inches
Hardness	Hard, often layered	Hard, bounces on impact	Soft, delicate	Soft, crumbles easily
Associated Weather	Severe thunderstorms	Freezing rain, winter weather	Winter storms, cold fronts	Winter weather, often precedes heavier snow
Damage Potential	High (property, crops, injury)	Low to moderate (slipping hazard)	Low (weight accumulation, minor disruption)	Very low

As you can see, hail stands out due to its formation in violent thunderstorms, its potential for significant size, and its resulting destructive power.

Understanding Hail Size, Speed, and Severity

The size and speed of hailstones are critical factors in determining their potential for damage. When we discuss what is hail, these characteristics define its impact. The National Weather Service (NWS) defines large hail as being at least 1 inch in diameter (the size of a quarter). Anything larger than that is considered severe and can cause significant damage.

From Peas to Grapefruits: A Guide to Hail Sizes

Hail size is often estimated by comparing it to common objects, which gives us an easy way to visualize its scale. From tiny peas to massive grapefruits, hailstones can vary dramatically.

Here’s a common comparison chart:

• Pea-sized: 1/4 inch (0.6 cm)
• Mothball-sized: 1/2 inch (1.3 cm)
• Penny-sized: 3/4 inch (1.9 cm)
• Nickel-sized: 7/8 inch (2.2 cm)
• Quarter-sized: 1 inch (2.5 cm) – This is the NWS threshold for severe hail.
• Ping-Pong Ball-sized: 1 1/2 inch (3.8 cm)
• Golf Ball-sized: 1 3/4 inches (4.4 cm)
• Tennis Ball-sized: 2 1/2 inches (6.4 cm)
• Baseball-sized: 2 3/4 inches (7.0 cm)
• Tea Cup-sized: 3 inches (7.6 cm)
• Softball-sized: 4 inches (10.2 cm)
• Grapefruit-sized: 4 1/2 inches (11.4 cm)

For more detailed comparisons, you can refer to the Hail size comparison chart from the Storm Prediction Center.

While comparing hail to objects is useful for quick reporting, accurate measurements with a ruler or calipers are always preferred by meteorologists.

Texas has seen its share of impressive hailstones. While the largest hailstone ever recovered in the United States was 8 inches in diameter and weighed almost 2 pounds, found in Vivian, South Dakota, in June 2010, our very own state holds a significant record. The largest hailstone in Texas history fell near Hondo, TX, in April 2021, measuring a staggering 6.416 inches. Imagine the impact of an ice chunk that size!

The Dangers of Large Hail: Speed and Impact Force

It’s not just the size of hail that makes it dangerous; it’s also the speed at which it falls. Hailstones are pulled down by gravity, and their terminal velocity (the maximum speed they reach) can be surprisingly high, especially for larger stones. This speed, combined with their mass, determines their kinetic energy and, consequently, their destructive power.

Here’s a look at expected fall speeds:

• Small hailstones (<1-inch in diameter): 9 to 25 mph.
• Hailstones in severe thunderstorms (1-inch to 1.75-inch in diameter): 25 to 40 mph.
• Large hailstones in strong supercells (2-inches to 4-inches in diameter): 44 to 72 mph.
• Very large hailstones (>4-inches in diameter): Can exceed 100 mph!

To put this into perspective, a baseball-sized hailstone can fall at about 100 miles per hour. When these icy projectiles strike property or living beings, the force of impact can be immense. This is why even a relatively short hailstorm can cause widespread and severe damage.

The Destructive Power of Hailstorms

Hailstorms are not just an inconvenience; they are a significant natural hazard capable of causing extensive damage and posing serious risks. The destructive power of hail comes from the kinetic energy of the falling ice, which increases exponentially with both size and speed.

We’ve seen in Houston, Dallas, Irving, and Plano, Texas, the devastation these storms can bring. From dented cars to shattered roofs, the aftermath of a severe hailstorm can be shocking.

The Economic Impact of Hail Damage

The financial toll of hailstorms is staggering. They cause billions of dollars in damage annually, making them one of the costliest weather phenomena, often surpassing the economic impact of tornadoes.

Consider these statistics:

• In 2021, approximately 6.8 million properties in the United States experienced at least one damaging hail event, resulting in an astounding $16.5 billion in losses.
• More recently, in 2023, hailstorms cost the United States an estimated $46 billion in damage to cars, roofs, and crops.
• Texas, unfortunately, bears a significant portion of this burden. In 2022, our state alone endured 458 major hail events. In 2021, Texas saw an estimated 1,591,074 properties damaged by hail, leading to a massive $5.1 billion in insurance claims.

This economic impact extends across various sectors. Insurance companies face a deluge of claims, leading to higher premiums and complex claim processes. For the agricultural industry, hailstorms can wipe out entire harvests in minutes, causing substantial financial losses for farmers and affecting food supply chains.

Understanding these figures underscores why preparedness and adequate insurance are so vital for Texas property owners. For more insights into the financial implications, refer to Insurance industry hail facts.

Common Property Damage and What is Hail’s Effect on Your Home

When a hailstorm sweeps through areas like Houston, Dallas, Irving, or Plano, the impact on homes and businesses can be severe and widespread. Here’s a look at the common types of property damage we regularly address:

• Roofing Damage: This is often the most significant and costly damage. Hailstones can bruise, crack, or puncture asphalt shingles, dislodge granules, and even create holes. For metal roofs, hail can cause cosmetic dents and compromise protective coatings. Over time, seemingly minor hail damage can lead to leaks, mold growth, and structural issues.
• Siding Damage: Vinyl, aluminum, and even wood siding can be severely impacted. Hailstones can cause cracks, chips, dents, and holes, compromising the aesthetic appeal and protective barrier of your home. You can find more information on this specific issue in our guide on Hail Damaged Siding.
• Window Damage: While less common than roof or siding damage, large hailstones can crack or shatter windows, skylights, and glass doors, leaving your property vulnerable to water intrusion and further damage.
• Gutters and Downspouts: These essential drainage systems are often made of lighter materials and are highly susceptible to denting, bending, or detachment during a hailstorm, impairing their ability to divert water away from your foundation.
• HVAC Units and Outdoor Appliances: Air conditioning units, pool heaters, and other outdoor equipment can suffer significant denting and damage to their sensitive fins and components.

Beyond the immediate visible damage, wind-driven hail can tear up siding and even break windows, allowing hail and water to blow directly into houses. This can lead to interior water damage, which, if not addressed promptly, can result in mold growth and compromised structural integrity. Our Storm Damage Siding Repair Guide offers valuable insights into addressing these issues.

Hail Hotspots, Forecasting, and Safety

Living in Texas means we’re no strangers to severe weather, and understanding hail hotspots, how it’s forecast, and what safety measures to take is crucial for protecting our communities in Houston, Dallas, Irving, and Plano.

Where and When Hail is Most Common

While hailstorms can occur anywhere the conditions are right, certain regions are more prone to them. Across the United States, the area known as “Hail Alley,” where Nebraska, Colorado, and Wyoming meet, averages seven to nine hail days per year.

However, Texas is routinely the state with the most number of hail events annually. Our unique geography and atmospheric conditions make us a prime location for these icy bombardments. Hail season in Texas generally falls within March and August, aligning with our peak severe weather season. During these months, warm, moist air from the Gulf of Mexico clashes with cooler, drier air masses, creating the unstable atmospheric conditions necessary for powerful thunderstorms to develop and produce hail.

How to Prepare for a Hailstorm and Protect Your Property

Preparation is key to minimizing damage and ensuring safety during a hailstorm. Here are some essential steps we recommend for property owners in Texas:

1. Monitor Weather Alerts: Stay informed by paying close attention to local weather forecasts and severe thunderstorm warnings. Services like the Storm Prediction Center’s Outlooks can provide advanced notice of hail probability.
2. Protect Vehicles: If possible, park your cars in a garage, carport, or under a sturdy overhead structure. If no covered parking is available, consider using thick blankets or floor mats to protect your vehicle’s windshield and roof as an emergency measure. If you’re driving and a hailstorm hits, pull over safely out of traffic, park away from trees or power lines, and wait for the storm to pass.
3. Secure Outdoor Items: Bring in or secure any outdoor furniture, decorations, grills, and trash cans that could become airborne or damaged by hail.
4. Protect Plants and Pets: Bring pets indoors or ensure they have access to a sturdy, sheltered area. Move potted plants indoors or to a protected space.
5. Reinforce Property: While not always feasible for sudden storms, consider impact-resistant roofing materials if you’re due for a roof replacement. For windows, storm shutters can provide an extra layer of protection.
6. Know Your Shelter: If caught outdoors during a hailstorm, seek sturdy shelter immediately. Avoid underpasses or overpasses, as they can become dangerous traffic bottlenecks and do not offer adequate protection from hail.

Our comprehensive Texas Hail Storm Damage Guide offers more in-depth advice custom for our region.

Forecasting Hail with Technology

The role of technology in detecting and forecasting hail has advanced significantly. Weather radar, especially dual-polarization radar, is our primary tool. This technology can distinguish between different types of precipitation within a cloud – rain, hail, snow, or ice pellets – giving forecasters a clearer picture of what’s coming.

The National Severe Storms Laboratory (NSSL) developed the Hydrometeor Classification Algorithm (HCA), which uses dual-polarization radar data to automatically identify ten types of radar echoes, including hail. Forecasters also look for “hail spikes” on radar, which are radar signatures that indicate the presence of large hail.

Even public participation helps! Projects like NSSL’s Meteorological Phenomena Identification Near the Ground (mPING) collect volunteer reports from mobile apps. This crowd-sourced data helps researchers refine radar algorithms and improve the accuracy of hail detection.

Frequently Asked Questions About Hail

What is hail suppression and does it work?

The idea of suppressing or preventing hail formation has been around for decades, driven by the immense damage hailstorms cause. The most common method explored is “cloud seeding,” which involves injecting substances like silver iodide into potential hail-producing clouds. The theory is that these particles provide more nuclei for ice crystals to form, leading to a greater number of smaller hailstones that melt before reaching the ground, or simply smaller hailstones that cause less damage.

Historically, methods like ringing church bells or firing cannons were tried, with little to no scientific basis. While some studies, particularly from the Soviet Union, claimed significant reductions in crop damage (70-98%) using cloud seeding, these results have been difficult to replicate in Western trials. The scientific community remains divided, with many meteorologists concluding that there is limited proven effectiveness for hail suppression. It’s incredibly challenging to definitively prove that seeding prevented hail that would have otherwise occurred naturally.

Why do some thunderstorms turn green?

Sometimes, a severe thunderstorm will take on an eerie green or turquoise hue. This phenomenon is often associated with intense hailstorms. The exact reason for the green color isn’t fully understood, but the most accepted theory involves the scattering of sunlight by a large concentration of water and ice particles (including hail) within the storm.

When sunlight passes through a cloud with a high liquid water content and substantial hail, the blue light is scattered by the water and ice, while the red and yellow light is absorbed. This leaves the green light to penetrate through the cloud, giving it its characteristic color. The effect is often most noticeable when the sun is low in the sky. So, if you see a green thunderstorm, it’s a strong visual indicator that a severe storm, possibly carrying large hail, is brewing.

Can hail accumulate like snow?

Yes, absolutely! While we typically think of hail falling and bouncing, under certain conditions, it can accumulate in surprisingly deep layers, much like snow. This phenomenon is sometimes referred to as “deep hail” or “plowable hail.”

One notable example occurred on June 5, 2015, when hail up to four feet deep fell on one city block in Denver, Colorado. While this is an extreme case, accumulations of several inches are not uncommon in intense hailstorms, particularly in mountainous regions or areas with strong updrafts.

These hail accumulations can cause several problems:

• Traffic Hazards: If deep enough, hail on roadways can act exactly like an icy surface, causing vehicles to lose traction and making driving extremely dangerous.
• Flooding: As the accumulated hail melts, it can quickly overwhelm drainage systems, leading to flash flooding. This is a significant concern in urban areas like Houston, Dallas, Irving, and Plano, where rapid runoff can cause widespread water damage.
• Weight Load: Heavy accumulations can put stress on roofs, similar to heavy snowfall, though this is less common with hail due to its density.

Your Next Steps After a Texas Hailstorm

We’ve explored what is hail, delving into its scientific formation, its impressive and often dangerous sizes and speeds, and its significant destructive potential, particularly for our communities in Texas. From the intricate dance of supercooled water droplets in cumulonimbus clouds to the multi-billion dollar impact on properties and crops, hail is a force of nature that demands respect and preparedness.

For homeowners and businesses in Houston, Dallas, Irving, and Plano, understanding the risks associated with hailstorms is the first step toward safeguarding your property. While we can’t control the weather, we can control how we prepare and how we respond to its aftermath.

If your property has been impacted by a hailstorm, don’t delay in assessing the damage. Even seemingly minor hail impacts can compromise your roof, siding, and other exterior elements, leading to more severe problems down the line.

At Certified Water & Fire Restoration, we understand the urgency and stress that comes with storm damage. That’s why we offer 24/7 emergency property restoration services for water and storm damage. Our commitment to you includes a rapid 60-minute response, no upfront costs (as we work directly with your insurance), and a 2-year warranty on our work. We’re here to help you steer the aftermath of a hailstorm, from initial assessment to complete restoration.

For more information on how we can assist you with storm-related damage, please visit our services page: More info about storm damage services. Let us help you restore your peace of mind and your property.