Hail is a form of solid precipitation consisting of ice balls or lumps. Hailstorms are weather events that produce solid precipitation in the form of ice balls or lumps.
Hailstorms occur globally in countries. Germany, France, Croatia, Serbia, and Russia experience hail storms in southern regions. The United States sees hail in Nebraska, Colorado, Florida, and the Great Plains. Italy endures 20-30 hail days per year, with Lombardy, Piedmont, and Veneto facing the most storms.
Hail sizes range from pea (6.6 mm, < 1/4 inch) to dollar (76 mm, 3 inches). Pea-sized hail measures 6 mm (1/4 inch) in diameter, while quarter-sized hail measures 25 mm (1 inch) in diameter. Golf ball-sized hail measures 44 mm (1 3/4 inches) in diameter. Hail size impacts the amount of damage it causes, with quarter or larger hail causing damage to crops, vehicles, and buildings.
Hail and sleet are forms of frozen precipitation. Hailstones appear opaque with rough surfaces, while sleet pellets are transparent, smooth, and smaller than hailstones.
Hail forms in thunderstorm updrafts through a process. Water droplets freeze into hailstones at freezing levels in the atmosphere. Updrafts carry hailstones through multiple freezing-melting cycles, causing them to grow larger. Hailstones become heavy enough to fall as hail when gravity overcomes the updraft force at diameters of 5-10 millimeters (0.2-0.4 inch) or larger.
What is the definition of hail in weather?
Hail is a form of precipitation consisting of ice balls or lumps. Thunderstorm updrafts produce hail by carrying water droplets to freezing atmospheric levels. Hail ranges from small, compact lumps to balls. Hail causes damage to homes, cars, and livestock. Hail does not result in deaths.
What is a hailstone?
Hailstone is a form of precipitation consisting of ice balls with a diameter of 5 mm (0.2 inch) or more. Hailstones form in thunderstorms when updrafts carry water droplets to the freezing level of the atmosphere. Ice balls grow through accretion as they fall through layers of supercooled water droplets, which freeze onto the hailstone’s surface. Hailstones exhibit shapes including spherical, spheroidal, conical, or irregular forms. Hailstones range in size from a pea to a baseball, causing damage to crops, buildings, and vehicles in the United States.
Hailstone structure consists of alternating opaque and clear ice layers. The layered structure is visible as bands or rings within the hailstone. Hailstone ice is clear or translucent, but air bubbles make some layers appear white or opaque. Hailstones have a surface texture, pitted from collisions with other particles in storm clouds.
Hailstone size ranges from millimeters to centimeters in diameter. The record-breaking hailstone weighed 1.02 kg (2.25 pounds) and measured 330 mm (13 inches) in diameter. Hailstones grow larger through accretion as they cycle through the clouds, collecting more frozen water droplets. Hailstones fall to the ground when they become heavy for updrafts to support.
Factors influencing hailstone development include the strength of updrafts, temperature variations within the cloud, and the amount of supercooled water droplets. Strong updrafts allow hailstones to remain suspended longer, resulting in larger sizes. Temperature fluctuations create ice layers as hailstones move through different cloud regions.
What is the definition of a hail storm?
A hailstorm is a weather event that produces solid precipitation in the form of ice balls or lumps. Hailstorms feature hail accompanied by thunder and lightning, as defined by the Collins COBUILD Advanced Learner’s Dictionary. Hailstorms form when thunderstorm updrafts carry water droplets to freezing levels in the atmosphere, where they freeze into ice balls and grow in size as they fall. The National Weather Service defines hailstorms as storms that produce hail with a diameter of at least 5 mm (0.2 inch). Hailstorms cause damage to homes, cars, and aircraft, and can be dangerous if hailstones are large enough to cause injuries to people.
How does a hail storm form?
Hail storms form through thunderstorm updrafts carrying water droplets into freezing atmospheric levels. Water droplets freeze onto particles, creating hailstones. Hailstones grow by colliding with droplets as updrafts cycle them through clouds. Hailstones become heavy and fall as hail. Falling hailstones create a hail storm.
Raindrops are carried upward by thunderstorm updrafts into cold areas. Water rises and reaches freezing temperatures around 2,000-3,000 meters altitude. Ice forms when water droplets freeze onto particles like dust or salt. Supercooled water exists in liquid form below 0°C(32°F) in the storm cloud.
Hailstones form when ice balls collide with supercooled water droplets. Raindrops freeze into ice pellets in the cold upper regions of the cloud. Hailstones grow through repeated collisions and freezing processes. Colliding water drops freeze onto the surface of existing ice particles. Water evaporates from the ground and freezes on hailstone surfaces, adding new layers of ice.
Hailstones continue to grow larger as strong updrafts suspend them in the storm. Freezing cycles allow hailstones to accumulate ice layers and reach increased sizes. Hailstones fall when updrafts can no longer support their weight. Hail storms produce winds and roars as hailstones fall to the ground.
How long does a hail storm last?
Hailstorms last 15 minutes. Duration varies, ranging from 1 minute to over an hour. Factors like storm intensity and area affect length. Long-lasting hailstorms of 30-60 minutes cause damage. Brief hailstorms are long enough to damage crops, vehicles, and buildings. Hail falls in areas or long swaths spanning miles.
How to stay safe during a hail storm?
To stay safe during a hail storm, follow the guidelines outlined below.
- Seek shelter indoors immediately.
- Stay inside buildings or basements until the storm passes.
- Leave outdoor areas to avoid injury from hailstones.
- Avoid trees and power lines.
- Cover head and neck for protection.
- Bring pets inside to protect them.
- Pull over to a safe location if driving.
- Stop driving to prevent accidents or damage.
- Move to the center of the vehicle to minimize exposure to windows.
- Leave vehicles if they become unsafe.
- Seek shelter under objects if caught outside.
- Use blankets, pillows, or mattresses as shields.
- Fill gaps with towels.
- Prepare for power outages with flashlights and battery-powered radios.
- Shelter in interior rooms or hallways on the lowest floor.
- Bring first aid kits for potential injuries.
What countries have hail storms?
Hailstorms occur globally. Countries like Germany, France, Croatia, Serbia, and Russia experience hailstorms, especially in southern regions. Northern Italy, Tuscany, is prone to hail. India, China, and Australia face hailstorms in eastern areas. The United States experiences hail in Nebraska, Colorado, Florida, and Great Plains. Argentina, Brazil, South Africa, and Morocco encounter hailstorms.
Countries that have hail storms are listed in the table below.
| Country | Average Hail Days per Year | Regions Most Affected | Average Hail Storm Duration (minutes) | Average Hailstone Size (mm) | Average Annual Hail Damage (million USD) |
| France | 24 | Southwest (Aquitaine, Midi-Pyrénées) and Southeast (Provence-Alpes-Côte d'Azur) | 30-60 | 10-20 | 150-200 |
| Germany | 15 | Bavaria (Upper Bavaria, Lower Bavaria) and Baden-Württemberg (Black Forest, Swabian Jura) | 20-40 | 8-15 | 100-150 |
| Belgium | 20 | Flanders (East Flanders, West Flanders) and Wallonia (Hainaut, Namur) | 25-50 | 9-18 | 80-120 |
| Netherlands | 12 | Eastern (Gelderland, Overijssel) and Southern (Limburg, North Brabant) | 20-40 | 8-15 | 50-80 |
| Luxembourg | 10 | Ardennes (Diekirch, Vianden) and Moselle Valley (Grevenmacher, Remich) | 20-40 | 7-12 | 20-30 |
| Italy | 25 | Lombardy (Milan, Pavia), Piedmont (Turin, Cuneo), and Veneto (Venice, Padua) | 30-60 | 10-20 | 200-250 |
| Croatia | 15 | Eastern (Osijek-Baranja, Vukovar-Srijem) and Central (Zagreb, Karlovac) | 25-50 | 9-18 | 50-70 |
| Serbia | 20 | Vojvodina (Novi Sad, Subotica) and Šumadija (Kragujevac, Jagodina) | 30-60 | 10-20 | 80-100 |
| Switzerland | 15 | Western (Geneva, Vaud) and Southern (Ticino, Valais) | 25-50 | 9-18 | 100-120 |
| Austria | 20 | Lower Austria (Vienna, St. Pölten) and Burgenland (Eisenstadt, Oberwart) | 30-60 | 10-20 | 150-180 |
| Slovenia | 15 | Eastern (Maribor, Celje) and Central (Ljubljana, Kranj) | 25-50 | 9-18 | 30-50 |
| Spain | 25 | Catalonia (Barcelona, Girona), Aragon (Zaragoza, Huesca), and Navarre (Pamplona, Tudela) | 30-60 | 10-20 | 200-250 |
| Turkey | 15 | Western (Istanbul, Izmir) and Central (Ankara, Kayseri) | 25-50 | 9-18 | 100-120 |
| Armenia | 10 | Northern (Aragatsotn, Lori) | 20-40 | 7-12 | 10-20 |
| Azerbaijan | 10 | Northern (Ganja, Gazakh) | 20-40 | 7-12 | 10-20 |
| India | 25 | Indo-Gangetic Plain (Uttar Pradesh, Bihar) and Himalayan foothills (Uttarakhand, Himachal Pradesh) | 30-60 | 10-20 | 500-600 |
| China | 25 | Eastern (Shanghai, Jiangsu) and Southern (Guangdong, Guangxi) | 30-60 | 10-20 | 800-1000 |
| United States | 55 | Great Plains (Texas, Oklahoma, Kansas) and Midwest (Illinois, Indiana, Ohio) | 40-80 | 12-25 | 1000-1200 |
What state in the USA has the most hail storms?
Texas receives the most hail storms in the USA. Weather Fusion’s 2020 research analyzed 30 years of National Oceanic and Atmospheric Administration (NOAA) data. Texas experiences 57.3 annual hail storms. Oklahoma ranks second with 46.3 storms, Kansas third with 43.8, and Nebraska fourth with 42.1. Peak hail season occurs in May-June for these states.
Nebraska ranks second in hail storm frequency but falls behind Texas. The Cornhusker State reports 486 annual hail events on average. Nebraska experiences 319 hail storms per year, less than one-third of Texas’ frequency. The Great Plains location of Texas contributes to its high occurrence of hailstorms. Warm, moist air from the Gulf of Mexico collides with cool, dry air from Canada in Texas, creating conditions for hail formation.
What was the worst hail storm in history?
The worst hail storm in history occurred on April 30, 1888, in Moradabad, India. Hailstones reached 75 mm (3 inches) in diameter. The storm lasted 2 hours, killing 246 people and injuring over 1,600. It destroyed 20,000 homes and leveled villages. Meteorologists consider it the deadliest hail storm recorded.
What are the different size types of hail?
Hail sizes range from pea-sized (< 6.4 mm, < 1/4 inch) to dollar-sized (76 mm, 3 inches). The National Weather Service classifies sizes using objects: penny (19 mm, 3/4 inch), nickel (23 mm, 7/8 inch), quarter (25 mm, 1 inch), golf ball (38 mm, 1 1/2 inches), hen egg (51 mm, 2 inches), ball-sized (25-64 mm, 1-2 1/2 inches), and lime-sized (51 mm, 2 inches).
The different size types of hail are detailed in the table below.
| Hail Size Type | Diameter (inches) | Diameter (mm) | Weight (grams) | Terminal Velocity (mph) | Damage Potential |
| Pea | 0.25 | 6.4 | 0.2 | 20 | Minimal |
| Mothball/Penny | 0.75 | 19.1 | 2.5 | 40 | Light |
| Nickel | 0.88 | 22.4 | 4.5 | 50 | Moderate |
| Quarter | 1 | 25.4 | 7 | 60 | Moderate |
| Half Dollar | 1.25 | 31.8 | 12 | 70 | Significant |
| Ping Pong Ball | 1.5 | 38.1 | 20 | 80 | Significant |
| Golf Ball | 1.75 | 44.5 | 30 | 90 | Severe |
| Lime | 2 | 50.8 | 40 | 100 | Severe |
| Hen Egg | 2.25 | 57.2 | 55 | 110 | Extreme |
Hail size impacts the amount of damage it causes. Pea-sized hail or smaller is unlikely to cause damage. Quarter-sized hail or larger causes damage to crops, vehicles, and buildings. Golf ball-sized hail or larger causes damage to property. Hail damage severity depends on hailstone size, velocity, and surface type.
What is hail damage?
Hail damage refers to harm caused by hailstones to structures, vehicles, and objects. Hailstones create dents, dings, and scratched paint on vehicles. Roofs, siding, and windows suffer cosmetic and structural damage. Hailstorms damage asphalt shingles, vinyl siding, and aluminum gutters. Severity depends on hailstone size, velocity, and affected surface type.
Damage from hail includes roof, siding, and window damage. Roof hail damage costs between $5,000 to $15,000 to repair, depending on roof size and damage extent. Siding hail damage repair costs range from $3,000 to $10,000. Window replacement costs $500 to $2,000 per window, varying by size and type.
Vehicle hail damage manifests as dents, dings, and broken windows. Vehicle hail damage repair costs $2,500, with a range of $1,000 to $5,000 depending on damage severity. Paintless dent repair (PDR) costs $50 to $200 per dent.
Hailstone size, impact force, and storm duration affect hail damage severity. Larger hailstones cause extensive damage to property and vehicles. Hailstorms lasting longer increase the likelihood of damage.
Hail damage assessment involves inspections by insurance adjusters or contractors. Insurance companies require claim submissions, including damage documentation and repair cost estimates. Hail damage claims totaled over $14 billion in insured losses in 2020. Hail damage claims account for up to 70% of all property damage claims in some regions.
Repair methods vary depending on the damaged surface. Roofing materials, siding, windows, and vehicle body parts require replacement. Techniques like paintless dent repair address vehicle body damage. Prevention strategies include using impact-resistant roofing materials and parking vehicles in covered areas during hailstorms.
What damage can hail cause?
Hail tears through roofs and breaks windows in houses, allowing water entry and causing damage. Houses suffer extensive structural harm. Cars sustain broken windshields and dented body panels. Severe hailstorms result in death and injury to people caught outside. Hail inflicts damage on structures and objects.
The damage that hail can cause is outlined below.
- Property damage from hail - Hailstones impact roofs, dent gutters and siding, shatter windows, and tear various cladding materials, leading to structural compromise and costly repairs.
- Vehicle damage from hail - Hailstones dent vehicle bodies, damage paint, and break vehicle windows and windshields, requiring extensive repairs and contributing to significant financial losses annually.
- Agricultural damage from hail - Hailstones puncture and bruise agricultural produce, break branches, strip plants, and substantially reduce crop yields, posing significant economic threats to the farming industry.
- Threat to living beings from hail - Hailstones cause injuries to humans and animals caught outdoors, with larger stones posing severe risks due to their size and weight.
Property damage from hail is severe and costly. Hail damages roofs by denting gutters, cracking siding, and affecting shingles, leading to leaks and potential collapse. Hail breaks windows and shatters glass, compromising the integrity of buildings. Hail tears vinyl siding, aluminum siding, and types of exterior cladding, resulting in repairs.
Vehicle damage is a consequence of hailstorms. Hail dents vehicles, causing damage to the body and paint. Hail shatters windshields and breaks windows of vehicles, necessitating repairs. The National Oceanic and Atmospheric Administration (NOAA) reports that hail causes an average of $1 billion in damages each year in the United States.
Agricultural damage from hail is harmful to farmers and the industry. Hail damages crops by puncturing fruits, bruising vegetables, and damaging leaves, reducing yields by up to 50%. Hail breaks branches and strips plants, affecting plant growth and term productivity. A hail storm in 2019 in India caused damage to crops, with estimated losses of over $1.3 billion.
Hail poses a serious threat to living beings caught in its path. Hail injures people if they are caught outside during a hail storm. Hail harms animals, those in outdoor enclosures or pastures, causing injury and stress. Hailstones reaching sizes of up to 200 mm (8 inches) in diameter and weighing up to 0.9 kg (1.9 pounds) inflict severe damage to both humans and animals.
What size hail causes damage to cars?
Hail causes damage to cars at different sizes. Paint damage occurs from 6.4 mm (1/4 inch) hailstones. Damage, including dents and scratches, results from 13 mm (1/2 inch) or larger hailstones. Hailstones break windshields and other glass components of cars. Car hoods and roofs are vulnerable. Damage severity depends on hailstone velocity, impact angle, and vehicle type.
Golf ball-sized hail (44.5 mm, 1.75 inches) generates dents and damage to vehicles. Tennis ball-sized hail (64 mm, 2.5 inches) inflicts damage on automobiles. Softball-sized hail (102 mm, 4 inches) causes damage to cars.
Vehicle type, paint quality, and bodywork condition influence the extent of hail-induced damage. Hail-damaged vehicles require inspection by professionals to ensure addressing of the damage.
What determines the size of hail?
Hail size depends on thunderstorm updraft strength. Stronger updrafts suspend hailstones longer, allowing them to grow larger by accumulating more frozen water droplets. Weaker updrafts produce smaller hail that falls sooner. Winds within storms disperse hailstones, limiting growth. Hailstones fall when they become too heavy for updrafts to support.
Hail size depends on how long the updraft supports growth. Updrafts reaching speeds up to 100 km/h (62 mph) sustain hailstones for extended periods. Longer suspension times result in larger hailstones, exceeding 150 mm (6 inches) in diameter. Weak updrafts allow hailstones to fall quickly, limiting their growth potential. Hail sizes vary, ranging from pea-sized (6-8 mm, 0.2-0.3 inch) to softball-sized (100-150 mm, 4-6 inches). Meteorologists use the hail scale to categorize sizes.
What’s the biggest hail ever recorded?
The heaviest hailstone recorded fell in Bangladesh in 1986. The record-breaking hailstone weighed 1.02 kg (2.25 pounds) and measured 330 mm (13 inches) in diameter. Bangladesh’s hailstone surpassed other notable events, including the 2010 Oklahoma hailstorm. The World Meteorological Organization verified this record. The Journal of Applied Meteorology and Climatology documented it.
Several other notable hailstones have been documented across the United States. A 178 mm (7 inches) diameter hailstone fell in Potter, Nebraska on June 22, 2003. Hondo, Oklahoma experienced a 163 mm (6.42 inches) diameter hailstone on May 11, 1990. Walter, Alabama recorded a 137 mm (5.38-inch) diameter hailstone on June 4, 1998. Colorado saw a 133 mm (5.25-inch) diameter hailstone on July 11, 1990.
What’s the difference between hail and sleet?
Hail and sleet are frozen precipitation types. Hailstones grow through repeated freezing in thunderstorm updrafts, reaching sizes from pea to baseball. Sleet forms when snowflakes melt and refreeze into ice pellets. Hailstones appear opaque with rough surfaces. Sleet pellets are transparent, smooth, and smaller than hailstones.
The size and appearance of hail and sleet are different. Hail grows into solid balls of ice, ranging from millimeters to centimeters in diameter. Sleet falls as pellets, measuring 1-5 mm (0.02-0.5 inch) in diameter. Hail appears transparent or translucent with a smooth, round shape. Sleet has an opaque appearance with an irregular or needle shape.
Hail and sleet exhibit contrasting properties. Hail melts slowly due to its compact ice composition. Sleet is soft and fragile, melting upon contact with surfaces. The associated weather phenomena for each are distinct. Hail accompanies thunderstorms, rain, and winds. Sleet is associated with snow, freezing rain, and icy conditions.
What’s the difference between hail and snow?
Hail forms through updrafts carrying water droplets to freezing levels in thunderstorms. Cold air freezes droplets into ice balls, growing as they accumulate more water. Snow results from water vapor freezing into ice crystals below 0°C (32°F). Graupel, or hail, occurs when supercooled droplets freeze onto falling snowflakes. Hail is larger than snow.
Hail and snow have distinct physical characteristics. Hailstones range from millimeters to centimeters in diameter. Snowflakes range from millimeters to centimeters. Hailstones have a spherical or irregular shape. Snowflakes exhibit a hexagonal or plate shape. Hail consists of transparent or translucent ice. Snow comprises branching ice crystals. Hail has a density of 0.9-1.0 g/cm³. Snow has a density of 0.1-0.5 g/cm³.
Hail and snow occur in different weather patterns. Hail occurs commonly during spring and summer months. Snow occurs during winter months. Hail is associated with thunderstorms, including supercells. Snow is associated with winter storms like nor’easters and blizzards.
Hail and snow differ in their initial state and growth mechanism. Hail forms from water droplets that freeze. Snow forms from water vapor that freezes into crystals. Hail grows by accumulating additional freezing water droplets. Snow grows by accumulating additional freezing water vapor.
Hail and snow have different impacts and behaviors. Hail causes damage to surfaces when large. Snow causes less damage than hail. Hail produces a rattling sound when falling. Snow produces a muffled sound when falling. Hail accumulates in a scattered pattern. Snow accumulates in a uniform layer. Hail melts slower than snow due to its size and density. Snow melts quicker than hail.
Hail and snow are associated with different weather conditions. Hail is associated with thunderstorms, rain, and winds. Snow is associated with cold temperatures, low humidity, and gentle winds.
What is the difference between hail and graupel?
Hail forms through layers of ice accumulation in thunderstorms, resulting in balls up to tennis ball size. Graupel develops from a single freezing process of supercooled water droplets, creating smaller pellets 2-5 mm (0.07-0.2 inch) in diameter. Hail has a solid, icy texture. Graupel breaks apart.
Graupel forms when supercooled water droplets freeze onto falling snowflakes. Hail forms in thunderstorms when updrafts carry water droplets to freezing levels. Graupel consists of snow coated with ice. Hail comprises ice.
Graupel has a soft and fragile texture. Hail has a solid texture. Graupel disintegrates upon impact or handling. Hail withstands impact due to its solid nature.
Graupel measures 2-5 mm (0.07-0.2 inch) in diameter. Hail ranges from 5-150 mm (0.2-6 inch) in diameter. Graupel can be crushed due to its soft texture. Hail resists crushing due to its ice composition.
Graupel has a density of 0.1-0.3 g/cm³. Hail has a density of 0.8-0.9 g/cm³. Graupel resembles small white pellets or balls. Hail looks like transparent or translucent ice balls.
What is the difference between hail and ice pellets?
Hail forms in thunderstorm updrafts as ice balls. Ice pellets, called sleet, develop when snowflakes melt and refreeze into small ice pieces. Hailstones grow larger through accumulation. Ice pellets maintain consistent size. “Hail” incorrectly describes ice pellets in English. Snow pellets differ from both, forming when supercooled droplets freeze onto snowflakes.
Temperature conditions for formation vary between hail and ice pellets. Hail requires temperatures between -10°C and -20°C (14 to -4°F) to form. Ice pellets form in temperatures between -5°C and -15°C (23 to 5°F). Shape is another characteristic. Hailstones have spherical or irregular shapes. Ice pellets possess spherical shapes.
Hardness levels differ between hail and ice pellets. Hailstones exhibit a Mohs hardness of 5-6. Ice pellets have a Mohs hardness of 2-3. Seasonal occurrence patterns are distinct. Hail occurs in spring and summer. Ice pellets occur in winter months.
Impact upon hitting the ground varies. Hail causes damage to crops, buildings, and vehicles. Ice pellets do not cause damage. Association with weather phenomena is a key differentiator. Thunderstorms, derechos, and squall lines produce hail. Storms, fronts, and lake-effect snow produce ice pellets.
How does hail form?
Hail forms in thunderstorm updrafts. Water droplets freeze into hailstones at freezing levels. Hailstones grow as supercooled water droplets freeze onto them. Strong updrafts carry hailstones through multiple freezing-melting cycles. Hailstones collide, forming larger hailstones. Hailstones become heavy to fall as hail. Warm, humid surface air and cold upper air create hail-forming conditions.
Water droplets freeze into ice crystals at temperatures below -10°C to -20°C (14 to -4°F) in the upper parts of the cloud. These ice crystals collide with supercooled water droplets, which freeze onto the crystal surface, forming the initial hailstone.
Hailstones grow larger as they are swept up and down through the clouds by strong updrafts. Each cycle through the freezing region adds another layer of ice to the hailstone, increasing its size through a process called accretion.
Hailstones become heavy as they accumulate more layers of ice. Gravity overcomes the updraft force when hailstones reach a diameter of 5-10 millimeters (0.2-0.4 inch) or larger. Hailstones fall through the clouds and reach the ground as hail.
Hail storms produce large amounts of hail in a short time. Updrafts in cumulonimbus clouds allow hailstones to grow to large sizes before falling. Hailstones vary in size, ranging from pea-sized to baseball-sized or larger in extreme cases.
What conditions are needed for hail to form?
Hail formation requires specific atmospheric conditions. Thunderstorms lift water droplets into freezing levels. Water droplets freeze into ice crystals. Updrafts carry ice crystals upward. Ice crystals collide with supercooled water droplets. Hailstones form and grow through accretion. Hailstones become heavy and fall to Earth. Vapor contributes to hailstone growth in some instances.
The conditions needed for hail to form are outlined below.
- Cumulonimbus clouds need a great vertical extent, exceeding 10 km (6.2 miles), providing an environment for hailstone growth.
- Cumulonimbus clouds must contain sufficient liquid water for hail development.
- Updrafts are critical for hail formation, as they lift water droplets to high altitudes at speeds up to 100 km/h (62 mph).
- Freezing levels exist at 2-3 km (1.2-1.9 miles) above ground, where water droplets freeze into small ice crystals, necessary for hail formation.
- Supercooled water droplets remain liquid below freezing and accrete onto growing hailstones.
- Frozen water droplets accrete water from surrounding supercooled droplets, increasing hailstone size.
- The cyclic process involving updrafts and downdrafts is essential for hail growth.
- Hailstones grow by passing through layers of supercooled droplets in the atmosphere.
- Hailstones fall when they become too heavy for updrafts to support.
Updrafts are essential for hail formation. Thunderstorm updrafts lift water droplets to high altitudes at speeds up to 100 km/h (62 mph). The freezing level in the atmosphere exists at 2-3 km (1.2-1.9 miles) above ground. Water droplets freeze into small ice crystals at this level.
Temperature conditions play a role in hail development. Supercooled water droplets remain liquid below freezing temperatures. Frozen water droplets accrete water from surrounding supercooled droplets. The accreted water freezes onto the hailstone as it falls, causing it to grow larger.
The hail formation process involves a cycle of upward and downward motion. Warm air rises and cold air descends in thunderstorms, creating updrafts and downdrafts. Updrafts carry the growing hailstone upward again. Hailstones grow by passing through layers of supercooled water droplets. The hailstone falls when it becomes heavy enough for updrafts to no longer support.
Why does hail only come from cumulonimbus clouds?
Cumulonimbus clouds form hail due to their structure. Updrafts carry raindrops high into freezing layers. Raindrops freeze into small ice balls. Updrafts lift ice balls through supercooled water layers. Ice balls grow into hailstones. Tall cloud structure and updrafts enable hailstone formation and growth.
Updrafts and convection currents in cumulonimbus clouds carry raindrops up into freezing temperatures. Upper regions of cumulonimbus clouds contain supercooled water droplets that remain liquid below freezing point. Water droplets freeze onto ice particles when they come into contact, forming larger ice particles. Ice particles move upward and downward through the cloud, passing through layers of supercooled water. Hailstones grow in size as they cycle through the cloud multiple times.
Hail forms in cumulonimbus clouds when updrafts are strong enough to carry ice particles upward but not strong enough to eject them from the cloud. Freezing temperatures in the upper regions of cumulonimbus clouds create conditions for hail formation. Supercooled water droplets freeze onto existing ice particles, increasing their size and weight. Hailstones become heavy enough to fall towards the ground when they reach diameters of up to 150 mm (5.9 inches) or more.
Hail storms are associated with thunderstorms produced by cumulonimbus clouds. Cumulonimbus clouds create low-pressure areas near their base, driving updrafts. Updrafts carry water droplets and hailstones upward through multiple freezing layers. Hailstones accumulate layers of ice as they pass through regions of supercooled water droplets.
What temperature does it have to be to hail?
Hail formation requires freezing temperatures above 0°C (32°F) in storm updrafts, not at ground level. Updrafts in storms carry water droplets to altitudes where they freeze into ice. Surface temperatures during hail are 10-20°C (50-68°F), while upper storm levels reach -20°C (-4°F) or below.
Surface temperatures during hail events vary . Hailstorms occur when surface temperatures reach 29°C (85°F). Temperatures before a hailstorm are high (32°C, 90°F). Surface temperatures drop after a hailstorm passes, falling to around 21°C (70°F). Temperature drops indicate an approaching cold front or strong updraft, which contribute to hail formation.
How does hail form in the summer?
Thunderstorms create updrafts in summer. Updrafts carry water particles to freezing levels in the atmosphere. Water droplets freeze onto ice nuclei at -20°C to -30°C (-4 to -22°F). Particles grow into hailstones by collecting water droplets. Hailstones fall when gravity overcomes updraft strength.
What are the facts about hailstorms?
Hailstorms occur 15 times annually in the United States. Supercell thunderstorms produce hail. Updrafts lift water droplets to freezing levels, forming ice balls. Hailstones range from pea-sized to baseball-sized. Heavy hail accumulates, causing damage. Smaller hailstones damage crops. Weather forecasters struggle to predict hail storms. Hailstorms result in injuries and fatalities.
The facts about hail storms are outlined below.
- Hail storms form in thunderstorms with updrafts exceeding 80.5 km/h (50 mph).
- Thunderstorms produce hail storms when updrafts lift water droplets to freezing levels in the atmosphere.
- Ice crystals grow into hailstones by circulating within the storm during hail storms.
- Supercell thunderstorms produce damaging hail storms due to their intense rotating updrafts.
- Hail storms last between minutes to hours, averaging 5-10 minutes.
- Hail storms cause damage to crops, buildings, and vehicles.
- Severe hail storms can injure people and animals.
- Hail Alley features frequent hail storms, encompassing parts of Texas, Oklahoma, Colorado, and Wyoming.
- The National Weather Service describes hail sizes with reference objects such as peas, golf balls, or baseballs during hail storms.
- The largest hail storm in the USA was recorded in Vivian, South Dakota in 2010, with 203 mm (8 inches) hailstones.
- The worst hail storm in history occurred on April 30, 1888, in Moradabad, India with hailstones reaching 750 mm (3 inches) in diameter and weighing 1.02 kg (2.25 lbs).
- Hail storms occur when thunderstorms generate hail that reaches the ground.
Is hail ice?
Hail is a form of solid ice. Hail forms when water droplets freeze into balls called hailstones in cumulonimbus clouds. Hailstones grow through accretion as they fall through layers of supercooled water droplets. Hail ranges in size from millimeters to over 15 centimeters in diameter.
Can you eat hail?
Hail is safe to eat in low quantities. Hail ice forms from water droplets in thunderstorms, making it frozen rainwater. Hail water contains few impurities due to the freezing process. Hail food lacks nutritional value and must not replace regular meals.
Health concerns exist when consuming hail. Hail ice contains contaminants like dust or pollutants. Bacteria from the environment are present on hail surfaces. Hail health risks increase with larger quantities consumed.
Hail taste resembles ice with a flavor. Hail flavor has notes from atmospheric elements. Hail mouth sensations include intense cold and a crunchy texture. Hail is not recommended due to lack of nutritional value and safety concerns.
Enthusiasts use hail as a novelty addition to drinks or desserts. Fruits and vegetables damaged during storms are unsafe for consumption. Hail damage compromises produce quality and increases the risk of bacterial growth. Hail storm debris contaminates fallen hailstones, requiring cleaning before consumption.
Safety precautions are crucial when eating hail. Hailstones pose a risk of dental damage. Clean hail before consumption to remove surface contaminants. Limit hail intake to avoid potential gastrointestinal issues or hypothermia.
Is hail precipitation?
Hail is precipitation. Precipitation encompasses solid and liquid forms of water falling from clouds. Hail forms when updrafts in thunderstorms carry water droplets to freezing levels. Freezing levels have temperatures below 0°C (32°F). Hailstones range from pea-sized (5-10 mm, 0.2-0.4 inch) to tennis ball-sized (10-15 cm, 0.4-0.6 inch) or beyond.
Hail starts as tiny ice particles. Water droplets freeze onto dust or particles at temperatures below -20°C (-4°F). Hailstones grow larger as they move through the storm. Layers of ice accumulate on the hailstones through accretion.
How is hail measured?
Hail measurement uses diameter as the metric. Sizes range from pea-sized (6.6 mm, 1/4 inch) to baseball-sized (70 mm, 2.75 inches). Inches and centimeters serve as units. Hail gauges, rulers, tape measures, and calipers determine sizes. The National Weather Service recommends measuring after storms for safety. Standardized categories ensure consistent reporting across agencies.
Indirect measurement techniques provide data on hail size and intensity. Scientists melt hail to measure its liquid equivalence, which correlates to hailstone size. Weather services utilize Doppler radar systems to detect hailstones in the atmosphere and estimate their size based on signal returns.
Hail measurement contributes to severe weather reporting and analysis. Meteorologists categorize hail intensity using scales, with hail sizes ranging from pea-sized to softball-sized or larger. Storm reports include hail size information in millimeters or inches for severity assessment. Hail charts provide graphical representations of hail sizes, aiding in the documentation of size, amount, and distribution of hailstones during a hail event.
How rare is hail?
Hail occurs in a percentage of thunderstorms. Researchers estimate hail forms in 6% to 15% of thunderstorms in the United States. The probability of hail within 19 km (12 miles) of a location is 1% to 3%.
Hail reports have increased over time. Hail reports tripled between the mid-1980s and 2000. The National Oceanic and Atmospheric Administration (NOAA) reports an average of 5,400 hail reports in the United States.
Hail causes few injuries and fatalities. The National Weather Service reports an average of 24 annual hail injuries in the United States. One death from hail has been reported in the U.S. since 2000.
Significant hail is rarer than typical hail. Hail sizes vary in thunderstorms. Large hail has a diameter of 51 mm (2 inches) or larger. Large hail causes damage to crops, buildings, and vehicles.
When does hail season start?
Hail season starts in May or June during late spring and early summer. Thunderstorms become frequent and severe during this period. The Northern Hemisphere experiences hail season from May 15 to July 15. The United States encounters peak hail activity in June, while Canada’s peak occurs in July. NOAA reports 5,400 average annual hail events between May and June.
June marks the start of hail season for some locations with seasons, such as the Northern United States and Canada. These regions experience a hail season, with most hail events occurring between June and August. September brings a peak in hail activity for areas in the Southern United States and parts of Asia. Remnants of tropical cyclones and the interaction between tropical and mid-latitude air masses contribute to this peak. Hail season ends around September or October in regions, though specific end dates vary depending on location and climate.
How to prepare for the upcoming hail season?
To prepare for the upcoming hail season, follow the steps outlined below.
- Trim trees and remove branches at least 2-3 weeks before hail season.
- Check and repair roofs.
- Clean and inspect gutters for damage to prevent water buildup.
- Review insurance policies to confirm coverage for hail damage.
- Bring furniture, decorations, and vehicles inside or cover them with hail-resistant materials.
- Secure outdoor items.
- Keep vehicles in covered parking.
- Provide shelter for animals and livestock in sturdy structures or barns.
- Stay indoors during hail storms to avoid injury from falling ice.
- Monitor weather forecasts and warnings daily through local news or weather apps.
- Keep emergency supplies like water, non-perishable food, and first-aid kits on hand.
- Prepare a room or basement with essential items for access during severe storms.
What is the hail risk score?
Hail risk score quantifies the likelihood and severity of hail impact in an area. Insurance companies utilize this score to assess claim risks and adjust policy premiums. Data, frequency of hail events, and estimated loss potential contribute to the calculation. Higher scores indicate greater probability of hail-related damage and increased average annual losses.
Is it safe to drive in hail?
Driving in hail is hazardous. Hail compromises visibility, increases stopping distances, and causes vehicle damage. Drivers pull over to safe locations like covered parking lots or shoulders. Waiting out the storm is crucial. Slow driving and increased following distance improve safety if pulling over is impossible.
Vehicle damage is a concern when driving in hail. Hailstones reach speeds of up to 160 km/h (100 mph), causing damage to windshields, headlights, and bodywork. Broken glass from shattered windshields poses a serious risk to drivers and passengers.
Drivers caught in a hailstorm must seek shelter immediately. Safe locations include parking garages, sturdy buildings, or any covered area that provides protection from falling hail. Overpasses and bridges do not offer shelter and are unsafe locations during severe weather.
If shelter is unavailable, drivers must pull off the road and stop their vehicles. Staying inside the vehicle provides protection than being outside during a hailstorm. Drivers turn on headlights and hazard lights to increase visibility to other motorists.
Slowing down is crucial for maintaining control in hail. Drivers reduce speed and use low gear to minimize skidding risks. Maintaining distance from other vehicles and avoiding movements helps prevent collisions.
The Insurance Institute for Highway Safety reports that 70% of hail-related crashes occur between May and August. 60% of these accidents happen in daylight, with a speed of 64 km/h (40 mph). Passenger cars account for 70% of vehicles involved in hail-related accidents, while pickup trucks comprise 20%.
Why is hail dangerous?
Hail tears off roofs, breaks windows, and damages siding on houses. Hailstones cause blunt force trauma, leading to death in people and animals. Hail shatters vehicle windshields and dents body panels. Falling at high speeds, hailstones pose injury risks. Hail disrupts life, damages crops, and causes property destruction.
Property damage from hail costs billions of dollars in the United States. Hail breaks windows in buildings and shatters car windshields. Hailstones dent vehicle bodies and damage aircraft wings and fuselage. Hail strips siding from homes and punctures roofs, leading to repairs.
Agricultural impacts of hail are devastating. Hail strips plants of foliage, breaks branches, and knocks grain stalks to the ground. Hailstones bruise fruits, puncture vegetables, and kill crops. Livestock left outside during hail storms suffer injuries or death. A 2019 hailstorm in India killed over 100 cattle and sheep.
Hail causes power outages and infrastructure damage. Hail breaks power lines and brings down trees onto electrical systems. Hail contributes to flash flooding by overwhelming drainage systems. Melting hail triggers mudslides in areas with steep terrain.
How fast does hail fall?
Hailstones fall at 40 km/h (25 mph). Diameter determines fall speed. 25 mm (1-inch) hailstones are expected to fall at 40 km/h (25 mph). 51 mm (2-inch) hailstones are expected to fall at 64 km/h (40 mph). Storms produce hailstones up to 102 mm (4 inches), falling at speeds over 80.5 km/h (50 mph). NOAA found 25 mm (1-inch) hailstones fall at 64-80.5 km/h (40-60 mph).
Hail speed correlates with its damage potential. Faster-falling hailstones inflict severe damage to structures, vehicles, and crops. Hail formed in updrafts grows larger and falls at higher velocities. Hailstorms cause destruction due to the forceful impact of descending hailstones. Researchers studying hail have confirmed the relationship between fall speed and damage severity.
Has anyone ever died from hail?
Hail has caused deaths worldwide. People have died from strikes and accidents. Fatalities remain rare, accounting for less than 1% of weather-related deaths. Records show 15-20 hail-related fatalities between 1900-2000. Incidents include 20 deaths in China (2010) and 15 in India (2018).
Hail injuries are more common than fatalities. The study reported 281 hail-related injuries between 1990 and 2010 in the United States. Injuries from hail range from cuts to head trauma. Hailstones cause blunt force trauma leading to head injuries and death. Hail has caused fatalities through power outages and building collapses. A hail storm in Texas caused a power outage leading to a fatal house fire in 2013.
Hail events have occurred worldwide. A hailstorm in Bangladesh in 1986 caused 92 injuries and 92 deaths. Hail storms occur commonly in mid-latitudes, with the United States, India, and Bangladesh experiencing frequent severe hail storms. The peak hail season in the United States occurs between May and July. Texas, Oklahoma, and Kansas experience the highest frequency of hail events in the U.S.
Record-breaking hailstones have been documented. The largest recorded hailstone in the United States fell in Vivian, South Dakota on June 23, 2010. The hailstone measured 203 mm (8 inches) in diameter and weighed 0.9 kg (1.9 pounds). Another hailstone in Oklahoma measured 165 mm (6.5 inches) in diameter and weighed 0.6 kg (1.3 pounds) in 2011. Hailstones larger than 51 mm (2 inches) are deadly.
Does hail indicate a tornado?
Hail does not indicate a tornado. Severe thunderstorms produce hail without tornadoes. Large hail (over 1 inch) is associated with tornadoes. NOAA reports 50% of tornadoes are accompanied by hail, but only 10% of hail-producing storms generate tornadoes. Supercells are likely to produce both hail and tornadoes.
Hail prediction and tornado potential are linked. The National Oceanic and Atmospheric Administration (NOAA) found tornado probability increases when hail is present in a storm. Hail frequency in severe storms is significant. The National Weather Service (NWS) reports hail report frequency increases before tornado events.
Probability of tornadoes in hail-producing storms is significant. The National Weather Service reports 70% of tornadoes occur in hail-producing storms. Tornado probability within 30 minutes of a hail report is 10-20%.
Hail radar signatures provide information for tornado indicators. Doppler radar detects hail intensity, size, and distribution, which helps estimate tornado probability. Hail appears as dense areas on radar images, with “hook” shapes.
Hail thunderstorm characteristics differ from tornado-producing storms. Hail thunderstorms produce hailstones with updrafts and downdrafts. Tornado-producing storms require factors like wind shear and instability.
Hail intensity correlates with tornado likelihood. The University of Oklahoma found hailstones increased tornado likelihood by a factor of 5. Large hail (diameter ≥ 1 inch or 2.5 cm) increases tornado likelihood.
Hail patterns are significant in tornado forecasting. The University of Colorado found hail falling in patterns is more likely to associate with tornado-producing storms. Hail swaths indicate long-lived updrafts, which are necessary for tornado formation.
Hail presence is one of several possible severe weather indicators. Tornado indicators include rotating updrafts (mesocyclones), sky, roaring sounds, and a low-hanging rotating wall cloud. Hail presence with other tornado indicators increases tornado likelihood.
Hail wind patterns relate to tornado formation. Winds are necessary conditions for tornado formation. Hail is likely to occur with strong winds (≥ 50 knots or 93 km/h) than with weak winds.