Hail is a form of solid precipitation. It is distinct from ice pellets (American English "sleet"), though the two are often confused.[1] It consists of balls or irregular lumps of ice, each of which is called a hailstone. Ice pellets fall generally in cold weather while hail growth is greatly inhibited during cold surface temperatures.[2]

Unlike other forms of water ice such as graupel, which is made of rime, and ice pellets, which are smaller and translucent, hailstones usually measure between 5 mm (0.2 in) and 15 cm (6 in) in diameter. The METAR reporting code for hail 5 mm (0.20 in) or greater is GR, while smaller hailstones and graupel are coded GS.

Hail is possible within most thunderstorms as it is produced by cumulonimbus,[3] and within 2 nmi (3.7 km) of the parent storm. Hail formation requires environments of strong, upward motion of air with the parent thunderstorm (similar to tornadoes) and lowered heights of the freezing level. In the mid-latitudes, hail forms near the interiors of continents, while in the tropics, it tends to be confined to high elevations.

There are methods available to detect hail-producing thunderstorms using weather satellites and weather radar imagery. Hailstones generally fall at higher speeds as they grow in size, though complicating factors such as melting, friction with air, wind, and interaction with rain and other hailstones can slow their descent through Earth's atmosphere. Severe weather warnings are issued for hail when the stones reach a damaging size, as it can cause serious damage to human-made structures and, most commonly, farmers' crops.

EffectExtreme damage, dents in metal
A large hailstone, about 6 cm (2.4 in) in diameter


Any thunderstorm which produces hail that reaches the ground is known as a hailstorm.[4] Hail has a diameter of 5 millimetres (0.20 in) or more.[3] Hailstones can grow to 15 centimetres (6 in) and weigh more than 0.5 kilograms (1.1 lb).[5]

Unlike ice pellets, hailstones are layered and can be irregular and clumped together. Hail is composed of transparent ice or alternating layers of transparent and translucent ice at least 1 millimetre (0.039 in) thick, which are deposited upon the hailstone as it travels through the cloud, suspended aloft by air with strong upward motion until its weight overcomes the updraft and falls to the ground. Although the diameter of hail is varied, in the United States, the average observation of damaging hail is between 2.5 cm (1 in) and golf ball-sized (1.75 in).[6]

Stones larger than 2 cm (0.80 in) are usually considered large enough to cause damage. The Meteorological Service of Canada issues severe thunderstorm warnings when hail that size or above is expected.[7] The US National Weather Service has a 2.5 cm (1 in) or greater in diameter threshold, effective January 2010, an increase over the previous threshold of ¾-inch hail.[8] Other countries have different thresholds according to local sensitivity to hail; for instance grape growing areas could be adversely impacted by smaller hailstones. Hailstones can be very large or very small, depending on how strong the updraft is: weaker hailstorms produce smaller hailstones than stronger hailstorms (such as supercells).


Hail forms in strong thunderstorm clouds, particularly those with intense updrafts, high liquid water content, great vertical extent, large water droplets, and where a good portion of the cloud layer is below freezing 0 °C (32 °F).[3] These types of strong updrafts can also indicate the presence of a tornado.[9] The growth rate of hailstones is impacted by factors such as higher elevation, lower freezing zones, and wind shear.[10]

Layer nature of the hailstones

Hail shaft

Like other precipitation in cumulonimbus clouds, hail begins as water droplets. As the droplets rise and the temperature goes below freezing, they become supercooled water and will freeze on contact with condensation nuclei. A cross-section through a large hailstone shows an onion-like structure. This means the hailstone is made of thick and translucent layers, alternating with layers that are thin, white and opaque. Former theory suggested that hailstones were subjected to multiple descents and ascents, falling into a zone of humidity and refreezing as they were uplifted. This up and down motion was thought to be responsible for the successive layers of the hailstone. New research, based on theory as well as field study, has shown this is not necessarily true.

The storm's updraft, with upwardly directed wind speeds as high as 110 miles per hour (180 km/h),[11] blows the forming hailstones up the cloud. As the hailstone ascends it passes into areas of the cloud where the concentration of humidity and supercooled water droplets varies. The hailstone's growth rate changes depending on the variation in humidity and supercooled water droplets that it encounters. The accretion rate of these water droplets is another factor in the hailstone's growth. When the hailstone moves into an area with a high concentration of water droplets, it captures the latter and acquires a translucent layer. Should the hailstone move into an area where mostly water vapour is available, it acquires a layer of opaque white ice.[12]

Hail clouds
Severe thunderstorms containing hail can exhibit a characteristic green coloration[13]

Furthermore, the hailstone's speed depends on its position in the cloud's updraft and its mass. This determines the varying thicknesses of the layers of the hailstone. The accretion rate of supercooled water droplets onto the hailstone depends on the relative velocities between these water droplets and the hailstone itself. This means that generally the larger hailstones will form some distance from the stronger updraft where they can pass more time growing.[12] As the hailstone grows it releases latent heat, which keeps its exterior in a liquid phase. Because it undergoes 'wet growth', the outer layer is sticky (i.e. more adhesive), so a single hailstone may grow by collision with other smaller hailstones, forming a larger entity with an irregular shape.[14]

Hail can also undergo 'dry growth' in which the latent heat release through freezing is not enough to keep the outer layer in a liquid state. Hail forming in this manner appears opaque due to small air bubbles that become trapped in the stone during rapid freezing. These bubbles coalesce and escape during the 'wet growth' mode, and the hailstone is more clear. The mode of growth for a hailstone can change throughout its development, and this can result in distinct layers in a hailstone's cross-section.[15]

The hailstone will keep rising in the thunderstorm until its mass can no longer be supported by the updraft. This may take at least 30 minutes based on the force of the updrafts in the hail-producing thunderstorm, whose top is usually greater than 10 km high. It then falls toward the ground while continuing to grow, based on the same processes, until it leaves the cloud. It will later begin to melt as it passes into air above freezing temperature.[16]

Thus, a unique trajectory in the thunderstorm is sufficient to explain the layer-like structure of the hailstone. The only case in which multiple trajectories can be discussed is in a multicellular thunderstorm, where the hailstone may be ejected from the top of the "mother" cell and captured in the updraft of a more intense "daughter" cell. This, however, is an exceptional case.[12]

Factors favoring hail

Hail is most common within continental interiors of the mid-latitudes, as hail formation is considerably more likely when the freezing level is below the altitude of 11,000 feet (3,400 m).[17] Movement of dry air into strong thunderstorms over continents can increase the frequency of hail by promoting evaporational cooling which lowers the freezing level of thunderstorm clouds giving hail a larger volume to grow in. Accordingly, hail is less common in the tropics despite a much higher frequency of thunderstorms than in the mid-latitudes because the atmosphere over the tropics tends to be warmer over a much greater altitude. Hail in the tropics occurs mainly at higher elevations.[18]

Hail growth becomes vanishingly small when air temperatures fall below −30 °C (−22 °F) as supercooled water droplets become rare at these temperatures.[17] Around thunderstorms, hail is most likely within the cloud at elevations above 20,000 feet (6,100 m). Between 10,000 feet (3,000 m) and 20,000 feet (6,100 m), 60 percent of hail is still within the thunderstorm, though 40 percent now lies within the clear air under the anvil. Below 10,000 feet (3,000 m), hail is equally distributed in and around a thunderstorm to a distance of 2 nautical miles (3.7 km).[19]


Hail occurs most frequently within continental interiors at mid-latitudes and is less common in the tropics, despite a much higher frequency of thunderstorms than in the mid-latitudes.[20] Hail is also much more common along mountain ranges because mountains force horizontal winds upwards (known as orographic lifting), thereby intensifying the updrafts within thunderstorms and making hail more likely.[21] The higher elevations also result in there being less time available for hail to melt before reaching the ground. One of the more common regions for large hail is across mountainous northern India, which reported one of the highest hail-related death tolls on record in 1888.[22] China also experiences significant hailstorms.[23] Central Europe and southern Australia also experience a lot of hailstorms. Regions where hailstorms frequently occur are southern and western Germany, northern and eastern France, and southern and eastern Benelux. In southeastern Europe, Croatia and Serbia experience frequent occurrences of hail.[24]

In North America, hail is most common in the area where Colorado, Nebraska, and Wyoming meet, known as "Hail Alley".[25] Hail in this region occurs between the months of March and October during the afternoon and evening hours, with the bulk of the occurrences from May through September. Cheyenne, Wyoming is North America's most hail-prone city with an average of nine to ten hailstorms per season.[26] To the north of this area and also just downwind of the Rocky Mountains is the Hailstorm Alley region of Alberta, which also experiences an increased incidence of significant hail events.

Three body scatter spike-NOAA
Example of a three-body spike: the weak triangular echoes (pointed by the arrow) behind the red and white thunderstorm core are related to hail inside the storm.

Short-term detection

Weather radar is a very useful tool to detect the presence of hail-producing thunderstorms. However, radar data has to be complemented by a knowledge of current atmospheric conditions which can allow one to determine if the current atmosphere is conducive to hail development.

Modern radar scans many angles around the site. Reflectivity values at multiple angles above ground level in a storm are proportional to the precipitation rate at those levels. Summing reflectivities in the Vertically Integrated Liquid or VIL, gives the liquid water content in the cloud. Research shows that hail development in the upper levels of the storm is related to the evolution of VIL. VIL divided by the vertical extent of the storm, called VIL density, has a relationship with hail size, although this varies with atmospheric conditions and therefore is not highly accurate.[27] Traditionally, hail size and probability can be estimated from radar data by computer using algorithms based on this research. Some algorithms include the height of the freezing level to estimate the melting of the hailstone and what would be left on the ground.

Certain patterns of reflectivity are important clues for the meteorologist as well. The three body scatter spike is an example. This is the result of energy from the radar hitting hail and being deflected to the ground, where they deflect back to the hail and then to the radar. The energy took more time to go from the hail to the ground and back, as opposed to the energy that went directly from the hail to the radar, and the echo is further away from the radar than the actual location of the hail on the same radial path, forming a cone of weaker reflectivities.

More recently, the polarization properties of weather radar returns have been analyzed to differentiate between hail and heavy rain.[28][29] The use of differential reflectivity (), in combination with horizontal reflectivity () has led to a variety of hail classification algorithms.[30] Visible satellite imagery is beginning to be used to detect hail, but false alarm rates remain high using this method.[31]

Size and terminal velocity

Hailstones ranging in size from few millimetres to over a centimetre in diameter.
Hagelkorn mit Anlagerungsschichten
Large hailstone with concentric rings

The size of hailstones is best determined by measuring their diameter with a ruler. In the absence of a ruler, hailstone size is often visually estimated by comparing its size to that of known objects, such as coins.[32] Using the objects such as hen's eggs, peas, and marbles for comparing hailstone sizes is imprecise, due to their varied dimensions. The UK organisation, TORRO, also scales for both hailstones and hailstorms.[33]

When observed at an airport, METAR code is used within a surface weather observation which relates to the size of the hailstone. Within METAR code, GR is used to indicate larger hail, of a diameter of at least 0.25 inches (6.4 mm). GR is derived from the French word grêle. Smaller-sized hail, as well as snow pellets, use the coding of GS, which is short for the French word grésil.[34]

Record hailstone Vivian, SD
The largest recorded hailstone in the United States.

Terminal velocity of hail, or the speed at which hail is falling when it strikes the ground, varies. It is estimated that a hailstone of 1 centimetre (0.39 in) in diameter falls at a rate of 9 metres per second (20 mph), while stones the size of 8 centimetres (3.1 in) in diameter fall at a rate of 48 metres per second (110 mph). Hailstone velocity is dependent on the size of the stone, friction with air it is falling through, the motion of wind it is falling through, collisions with raindrops or other hailstones, and melting as the stones fall through a warmer atmosphere. As hail stones are not perfect spheres it is difficult to calculate their speed accurately.[35]

Hail records

Megacryometeors, large rocks of ice that are not associated with thunderstorms, are not officially recognized by the World Meteorological Organization as "hail," which are aggregations of ice associated with thunderstorms, and therefore records of extreme characteristics of megacryometeors are not given as hail records.

  • Heaviest: 1.02 kg (2.25 lb); Gopalganj District, Bangladesh, 14 April 1986.[36][37]
  • Largest diameter officially measured: 7.9 inches (20 cm) diameter, 18.622 inches (47.3 cm) circumference; Vivian, South Dakota, 23 July 2010.[38]
  • Largest circumference officially measured: 18.74 inches (47.6 cm) circumference, 7.0 inches (17.8 cm) diameter; Aurora, Nebraska, 22 June 2003.[37][39]
  • Greatest average hail precipitation: Kericho, Kenya experiences hailstorms, on average, 50 days annually. Kericho is close to the equator and the elevation of 7,200 feet contributes to it being a hot spot for hail.[40] Kericho reached the world record for 132 days of hail in one year.[41]


Wea02208 - Flickr - NOAA Photo Library
Early automobiles were not equipped to deal with hail.

Hail can cause serious damage, notably to automobiles, aircraft, skylights, glass-roofed structures, livestock, and most commonly, crops.[26] Hail damage to roofs often goes unnoticed until further structural damage is seen, such as leaks or cracks. It is hardest to recognize hail damage on shingled roofs and flat roofs, but all roofs have their own hail damage detection problems.[42] Metal roofs are fairly resistant to hail damage, but may accumulate cosmetic damage in the form of dents and damaged coatings.[43]

Hail is one of the most significant thunderstorm hazards to aircraft.[44] When hailstones exceed 0.5 inches (13 mm) in diameter, planes can be seriously damaged within seconds.[45] The hailstones accumulating on the ground can also be hazardous to landing aircraft. Hail is also a common nuisance to drivers of automobiles, severely denting the vehicle and cracking or even shattering windshields and windows. Wheat, corn, soybeans, and tobacco are the most sensitive crops to hail damage.[22] Hail is one of Canada's most expensive hazards.[46]

Rarely, massive hailstones have been known to cause concussions or fatal head trauma. Hailstorms have been the cause of costly and deadly events throughout history. One of the earliest known incidents occurred around the 9th century in Roopkund, Uttarakhand, India, where 200 to 600 nomads seem to have died of injuries from hail the size of cricket balls.[47]


Accumulated hail in Sydney, Australia (April 2015).

Narrow zones where hail accumulates on the ground in association with thunderstorm activity are known as hail streaks or hail swaths,[48] which can be detectable by satellite after the storms pass by.[49] Hailstorms normally last from a few minutes up to 15 minutes in duration.[26] Accumulating hail storms can blanket the ground with over 2 inches (5.1 cm) of hail, cause thousands to lose power, and bring down many trees. Flash flooding and mudslides within areas of steep terrain can be a concern with accumulating hail.[50]

Depths of up to 18 in (0.46 m) have been reported. A landscape covered in accumulated hail generally resembles one covered in accumulated snow and any significant accumulation of hail has the same restrictive effects as snow accumulation, albeit over a smaller area, on transport and infrastructure.[51] Accumulated hail can also cause flooding by blocking drains, and hail can be carried in the floodwater, turning into a snow-like slush which is deposited at lower elevations.

On somewhat rare occasions, a thunderstorm can become stationary or nearly so while prolifically producing hail and significant depths of accumulation do occur; this tends to happen in mountainous areas, such as the July 29, 2010 case[52] of a foot of hail accumulation in Boulder County, Colorado. On June 5, 2015, hail up to four feet deep fell on one city block in Denver, Colorado. The hailstones, described as between the size of bumble bees and ping pong balls, were accompanied by rain and high winds. The hail fell in only the one area, leaving the surrounding area untouched. It fell for one and a half hours between 10 p.m. and 11:30 pm. A meteorologist for the National Weather Service in Boulder said, "It's a very interesting phenomenon. We saw the storm stall. It produced copious amounts of hail in one small area. It's a meteorological thing." Tractors used to clear the area filled more than 30 dump-truck loads of hail.[53]

Research focused on four individual days that accumulated more than 5.9 inches (15 cm) of hail in 30 minutes on the Colorado front range has shown that these events share similar patterns in observed synoptic weather, radar, and lightning characteristics,[54] suggesting the possibility of predicting these events prior to their occurrence. A fundamental problem in continuing research in this area is that, unlike hail diameter, hail depth is not commonly reported. The lack of data leaves researchers and forecasters in the dark when trying to verify operational methods. A cooperative effort between the University of Colorado and the National Weather Service is in progress. The joint project's goal is to enlist the help of the general public to develop a database of hail accumulation depths.[55]

Suppression and prevention

Banska Stiavnica Cannon-1
Hail cannon in an old castle in Banska Stiavnica, Slovakia

During the Middle Ages, people in Europe used to ring church bells and fire cannons to try to prevent hail, and the subsequent damage to crops. Updated versions of this approach are available as modern hail cannons. Cloud seeding after World War II was done to eliminate the hail threat,[11] particularly across the Soviet Union – where it was claimed a 70–98% reduction in crop damage from hail storms was achieved by deploying silver iodide in clouds using rockets and artillery shells.[56][57] Hail suppression programs have been undertaken by 15 countries between 1965 and 2005.[11][22]

See also


  1. ^ What's the difference between hail, sleet, and freezing rain? Archived 2014-02-02 at the Wayback Machine. The Straight Dope (1999-08-06). Retrieved on 2016-07-23.
  2. ^ "Merriam-Webster definition of "hailstone"". Merriam-Webster. Archived from the original on 2013-01-16. Retrieved 2013-01-23.
  3. ^ a b c Glossary of Meteorology (2009). "Hail". American Meteorological Society. Archived from the original on 2010-07-25. Retrieved 2009-07-15.
  4. ^ Glossary of Meteorology (2009). "Hailstorm". American Meteorological Society. Archived from the original on 2011-06-06. Retrieved 2009-08-29.
  5. ^ National Severe Storms Laboratory (2007-04-23). "Aggregate hailstone". National Oceanic and Atmospheric Administration. Archived from the original on 2009-08-10. Retrieved 2009-07-15.
  6. ^ Ryan Jewell; Julian Brimelow (2004-08-17). "P9.5 Evaluation of an Alberta Hail Growth Model Using Severe Hail Proximity Soundings in the United States" (PDF). Archived (PDF) from the original on 2009-05-07. Retrieved 2009-07-15.
  7. ^ Meteorological Service of Canada (November 3, 2010). "Severe Thunderstorm criteria". Environment Canada. Archived from the original on August 5, 2012. Retrieved 2011-05-12.
  8. ^ National Weather Service (January 4, 2010). "NEW 1 Inch Hail Criteria". NOAA. Archived from the original on September 7, 2011. Retrieved 2011-05-12.
  9. ^ National Weather Service Forecast Office, Columbia, South Carolina (2009-01-27). "Hail..." National Weather Service Eastern Region Headquarters. Archived from the original on 2009-04-12. Retrieved 2009-08-28.CS1 maint: Multiple names: authors list (link)
  10. ^ "FORECASTING HAIL". www.theweatherprediction.com. Retrieved 2018-08-08.
  11. ^ a b c National Center for Atmospheric Research (2008). "Hail". University Corporation for Atmospheric Research. Archived from the original on 2010-05-27. Retrieved 2009-07-18.
  12. ^ a b c Stephan P. Nelson (August 1983). "The Influence of Storm Flow Struce on Hail Growth". Journal of the Atmospheric Sciences. 40 (8): 1965–1983. Bibcode:1983JAtS...40.1965N. doi:10.1175/1520-0469(1983)040<1965:TIOSFS>2.0.CO;2. ISSN 1520-0469.
  13. ^ Frank W. Gallagher, III. (October 2000). "Distant Green Thunderstorms – Frazer's Theory Revisited". Journal of Applied Meteorology. American Meteorological Society. 39 (10): 1754. Bibcode:2000JApMe..39.1754G. doi:10.1175/1520-0450-39.10.1754.
  14. ^ Julian C. Brimelow; Gerhard W. Reuter; Eugene R. Poolman (2002). "Modeling Maximum Hail Size in Alberta Thunderstorms". Weather and Forecasting. 17 (5): 1048–1062. Bibcode:2002WtFor..17.1048B. doi:10.1175/1520-0434(2002)017<1048:MMHSIA>2.0.CO;2. ISSN 1520-0434.
  15. ^ Rauber, Robert M; Walsh, John E; Charlevoix, Donna Jean (2012). Severe & Hazardous Weather. ISBN 9780757597725.
  16. ^ Jacque Marshall (2000-04-10). "Hail Fact Sheet". University Corporation for Atmospheric Research. Archived from the original on 2009-10-15. Retrieved 2009-07-15.
  17. ^ a b Wolf, Pete (2003-01-16). "Meso-Analyst Severe Weather Guide". University Corporation for Atmospheric Research. Archived from the original on 2003-03-20. Retrieved 2009-07-16.
  18. ^ Thomas E. Downing; Alexander A. Olsthoorn; Richard S. J. Tol (1999). Climate, change and risk. Routledge. pp. 41–43. ISBN 978-0-415-17031-4. Retrieved 2009-07-16.
  19. ^ Airbus (2007-03-14). "Flight Briefing Notes: Adverse Weather Operations Optimum Use of Weather Radar" (PDF). SKYbrary. p. 2. Archived (PDF) from the original on 2011-05-31. Retrieved 2009-11-19.
  20. ^ W.H. Hand; G. Cappelluti (January 2011). "A global hail climatology using the UK Met Office convection diagnosis procedure (CDP) and model analyses". Meteorological Applications. Wiley. 18 (4): 446. Bibcode:2011MeApp..18..446H. doi:10.1002/met.236.
  21. ^ Geoscience Australia (2007-09-04). "Where does severe weather occur?". Commonwealth of Australia. Archived from the original on 2009-06-21. Retrieved 2009-08-28.
  22. ^ a b c John E. Oliver (2005). Encyclopedia of World Climatology. Springer. p. 401. ISBN 978-1-4020-3264-6. Retrieved 2009-08-28.
  23. ^ Dongxia Liu; Guili Feng; Shujun Wu (February 2009). "The characteristics of cloud-to-ground lightning activity in hailstorms over northern China". Atmospheric Research. 91 (2–4): 459–465. Bibcode:2009AtmRe..91..459L. doi:10.1016/j.atmosres.2008.06.016.
  24. ^ Damir Počakal; Željko Večenaj; Janez Štalec (July 2009). "Hail characteristics of different regions in continental part of Croatia based on influence of orography". Atmospheric Research. 93 (1–3): 516. Bibcode:2009AtmRe..93..516P. doi:10.1016/j.atmosres.2008.10.017.
  25. ^ Rene Munoz (2000-06-02). "Fact Sheet on Hail". University Corporation for Atmospheric Research. Archived from the original on 2009-10-15. Retrieved 2009-07-18.
  26. ^ a b c Nolan J. Doesken (April 1994). "Hail, Hail, Hail ! The Summertime Hazard of Eastern Colorado" (PDF). Colorado Climate. 17 (7). Archived (PDF) from the original on 2010-11-25. Retrieved 2009-07-18.
  27. ^ Charles A. Roeseler; Lance Wood (2006-02-02). "VIL density and Associated Hail Size Along the Northwest Gulf Coast". National Weather Service Southern Region Headquarters. Archived from the original on August 18, 2007. Retrieved 2009-08-28.
  28. ^ Aydin, K.; Seliga, T.A.; Balaji, V. (October 1986). "Remote Sensing of Hail with a Dual Linear Polarization Radar". Journal of Climate and Applied Meteorology. 25 (10): 1475–14. Bibcode:1986JApMe..25.1475A. doi:10.1175/1520-0450(1986)025<1475:RSOHWA>2.0.CO;2. ISSN 1520-0450.
  29. ^ Colorado State University-CHILL National Radar Facility (2007-08-22). "Hail Signature Development". Colorado State University. Archived from the original on 2009-01-07. Retrieved 2009-08-28.
  30. ^ Colorado State University-CHILL National Radar Facility (2008-08-25). "Hydrometeor classification example". Colorado State University. Archived from the original on 2010-06-24. Retrieved 2009-08-28.
  31. ^ Bauer-Messmer, Bettina; Waldvogel, Albert (1998-07-25). "Satellite data based detection and prediction of hail". Atmospheric Research. 43 (3): 217. Bibcode:1997AtmRe..43..217B. doi:10.1016/S0169-8095(96)00032-4.
  32. ^ Nebraska Rainfall Assessment; Information Network (2009). "NeRAIN Data Site-Measuring Hail". Nebraska Department of Natural Resources. Archived from the original on 2009-03-02. Retrieved 2009-08-29.
  33. ^ The TORnado; storm Research Organization (2009). "Hail Scale". Archived from the original on 2009-04-22. Retrieved 2009-08-28.
  34. ^ Alaska Air Flight Service Station (2007-04-10). "SA-METAR". Federal Aviation Administration. Archived from the original on May 1, 2008. Retrieved 2009-08-29.
  35. ^ National Severe Storms Laboratory (2006-11-15). "Hail Basics". National Oceanic and Atmospheric Administration. Archived from the original on 2009-05-06. Retrieved 2009-08-28.
  36. ^ World: Heaviest Hailstone | ASU World Meteorological Organization Archived 2015-06-29 at the Wayback Machine. Wmo.asu.edu. Retrieved on 2016-07-23.
  37. ^ a b "Appendix I – Weather Extremes" (PDF). San Diego, California: National Weather Service. Archived from the original (PDF) on 28 May 2008. Retrieved 2010-06-01.
  38. ^ NWS (30 July 2010). "Record Setting Hail Event in Vivian, South Dakota on July 23, 2010". Aberdeen, South Dakota: National Weather Service. Archived from the original on 3 August 2010. Retrieved 2010-08-03.
  39. ^ "Largest Hailstone in U.S. History Found". News.nationalgeographic.com. Archived from the original on 2010-04-20. Retrieved 2010-08-20.
  40. ^ "What Places in the World Usually Have the Most Hail in One Year?". 2013-04-12. Retrieved 2017-10-16.
  41. ^ Glenday, Craig (2013). Guinness World Records 2014. Guinness World Records Limited. p. 22. ISBN 9781908843159.
  42. ^ "Hail Damage to Roofs". Adjusting Today. Archived from the original on 2015-10-16. Retrieved 2009-12-11.
  43. ^ "Metal Roofing". Archived from the original on 2010-10-22.
  44. ^ P.R. Field; W.H. Hand; G. Cappelluti; et al. (November 2010). "Hail Threat Standardisation" (PDF). European Aviation Safety Agency. RP EASA.2008/5. Archived from the original (PDF) on 2013-12-07.
  45. ^ Federal Aviation Administration (2009). "Hazards". Archived from the original on 2010-03-25. Retrieved 2009-08-29.
  46. ^ Damon P. Coppola (2007). Introduction to international disaster management. Butterworth-Heinemann. p. 62. ISBN 978-0-7506-7982-4.
  47. ^ David Orr (2004-11-07). "Giant hail killed more than 200 in Himalayas". Telegraph Group Unlimited via the Internet Wayback Machine. Archived from the original on 2005-12-03. Retrieved 2009-08-28.
  48. ^ National Severe Storms Laboratory (2006-10-09). "Hail Climatology". National Oceanic and Atmospheric Administration. Archived from the original on 2009-06-13. Retrieved 2009-08-29.
  49. ^ Albert J. Peters (2003-03-03). "Crop Hail Damage Assessment" (PDF). Institut National De Recherche En Informatique Et En Automatique. Archived from the original (PDF) on 2011-07-21. Retrieved 2009-08-28.
  50. ^ Harold Carmichael (2009-06-15). "Sudbury lashed by freak storm; hail pummels downtown core". Sudbury Star. Sun Media. Archived from the original on 2009-06-16. Retrieved 2009-08-28.
  51. ^ Thomas W. Schlatter; Nolan Doesken (September 2010). "Deep Hail: Tracking an Elusive Phenomenon". Weatherwise. Taylor & Francis. 63 (5). ISSN 0043-1672. Retrieved 2015-08-09.
  52. ^ Rubino, Joe (2010-07-29). "Boulder County cleans up Nederland-area roadways after foot-deep hailstorm". Colorado Daily. Archived from the original on 2015-06-10. Retrieved 2014-12-20.
  53. ^ Mitchell, Kirk (5 June 2015). "One Denver block buried under up to 4 feet of hail". The Denver Post. Archived from the original on 6 June 2015. Retrieved 7 June 2015.
  54. ^ E. Kalina et. all (26 October 2015). "Colorado Plowable Hailstorms: Synoptic Weather, Radar and Lightning Characteristics". American Meteorological Society. 31 (2): 663. Bibcode:2016WtFor..31..663K. doi:10.1175/WAF-D-15-0037.1.
  55. ^ "Deep Hail Project – Report your hail depth!!". University of Colorado Boulder. Archived from the original on 2016-07-08.
  56. ^ Abshaev M. T., Abshaev A. M., Malkarova A. M. (22–24 October 2007). "Radar Estimation of Physical Efficiency of Hail Suppression Projects". 9th WMO Scientific Conference on Weather Modification. Antalya, Turkey. pp. 228–231.
  57. ^ Abshaev M. T., A.M. Abshaev and Malkarova A.M. (2012) "Estimation of antihail projects efficiency considering the tendency of hail climatology change". 10th WMO Conf. Weather Mod., Bali, Indonesia. WWRP 2012–2, pp. 1–4.

Further reading

  • Rogers and Yau (1989). A Short Course in Cloud Physics. Massachusetts: Butterworth-Heinemann. ISBN 0-7506-3215-1.
  • Jim Mezzanotte (2007). Hailstorms. Gareth Stevens Publishing. ISBN 978-0-8368-7912-4.
  • Snowden Dwight Flora (2003). Hailstorms of the United States. Textbook Publishers. ISBN 978-0-7581-1698-7.
  • Narayan R. Gokhale (1974). Hailstorms and Hailstone Growth. State University of New York Press. ISBN 978-0-87395-313-9.
  • Duncan Scheff (2001). Ice and Hailstorms. Raintree Publishers. ISBN 978-0-7398-4703-9.

External links

All Hail King Julien

All Hail King Julien is an American computer-animated television series. It stars King Julien, Maurice, and Mort from the DreamWorks Animation animated film Madagascar franchise and takes place in Madagascar and before the events of the first film making it a prequel. It is the second DreamWorks Animation show to be based on the Madagascar franchise.

The series debuted on December 19, 2014, on Netflix when the first five 22-minute episodes were released. Season 2 was released on October 16, 2015. Season 3 was released on June 17, 2016, and season 4 was released on November 11, 2016. During the course of the series, 65 episodes of All Hail King Julien, excluding the spin-off Exiled, released on May 12, 2017, were released over five seasons. The fifth and final season was released on December 1, 2017. It is currently showing reruns on Universal Kids and ABC Me.


The Angelus (; Latin for "angel") is a Catholic devotion commemorating the Incarnation. As with many Catholic prayers, the name Angelus is derived from its incipit—the first few words of the text: Angelus Domini nuntiavit Mariæ ("The Angel of the Lord declared unto Mary"). The devotion is practised by reciting as versicle and response three Biblical verses narrating the mystery, alternating with the prayer "Hail Mary". The Angelus exemplifies a species of prayers called the "prayer of the devotee".The devotion was traditionally recited in Roman Catholic churches, convents, and monasteries three times daily: 6:00 am, noon, and 6:00 pm (many churches still follow the devotion, and some practice it at home). The devotion is also used by some Anglican and Lutheran churches.

The Angelus is usually accompanied by the ringing of the Angelus bell, which is a call to prayer and to spread goodwill to everyone. The angel referred to in the prayer is Gabriel, a messenger of God who revealed to Mary that she would conceive a child to be born the Son of God (Luke 1:26–38).

Comet Hale–Bopp

Comet Hale–Bopp (formally designated C/1995 O1) is a comet that was perhaps the most widely observed of the 20th century, and one of the brightest seen for many decades.

Hale–Bopp was discovered on July 23, 1995, separately by Alan Hale and Thomas Bopp prior to it becoming naked-eye visible on Earth. Although predicting the maximum apparent brightness of new comets with any degree of certainty is difficult, Hale–Bopp met or exceeded most predictions when it passed perihelion on April 1, 1997. It was visible to the naked eye for a record 18 months, twice as long as the previous record holder, the Great Comet of 1811. Accordingly, Hale–Bopp was dubbed the Great Comet of 1997.


Discordianism is a paradigm based upon the book Principia Discordia, written by Greg Hill with Kerry Wendell Thornley in 1963, the two working under the pseudonyms Malaclypse the Younger and Omar Khayyam Ravenhurst. According to self-proclaimed "crackpot historian" Adam Gorightly, Discordianism was founded as a parody religion. Many outside observers still regard Discordianism as a parody religion, although some of its adherents may utilize it as a legitimate religion or as a metaphor for a governing philosophy.The Principia Discordia, if read literally, encourages the worship of the Greek goddess Eris, known in Latin as Discordia, the goddess of disorder, or archetypes and ideals associated with her. Depending on the version of Discordianism, Eris might be considered the goddess exclusively of disorder or the goddess of disorder and chaos. Both views are supported by the Principia Discordia. The Principia Discordia holds three core principles: the Aneristic (order), the Eristic (disorder), and the notion that both are mere illusions. Due to these principles, a Discordian believes there is no distinction between disorder and chaos, since the only difference between the two is that one refers to 'order'. This is likely a major reason for the inconsistency in the wording. An argument presented by the text is that it is only by rejecting these principles that you can truly perceive reality as it is, chaos.

It is difficult to estimate the number of Discordians because they are not required to hold Discordianism as their only belief system, and because, by nature of the system itself, there is an encouragement to form schisms and cabals.

Fight song

In American and Canadian sports, a fight song is a song associated with a team. In both professional and amateur sports, fight songs are a popular way for fans to cheer for their team, and are also laden with history; in singing a fight song, fans feel part of a large, time-honored tradition. Although the term "fight song" is primarily used in the United States, the use of fight songs is commonplace around the world, but they may also be referred to as team anthems, team songs or games songs in other countries, even such as Australia, Mexico and New Zealand. Fight songs differ from stadium anthems, used for similar purposes, in that they are usually written specifically for the purposes of the team, whereas stadium anthems are not.

Hundreds of colleges have fight songs, some of which are over a century old. The oldest collegiate fight song in the United States is Boston College's "For Boston", composed by T.J. Hurley in 1885.One of the oldest games songs in Australia is Melbourne Grammar's 'Play Together, Dark Blue Twenty', which is sung to the tune of 'The March of the Men of Harlech'. It was composed by Ambrose John Wilson who was principal of the school from 1885-1893. This is not to be confused with the school hymn 'Ora et Labora' which is now sung to the tune of 'Jerusalem'.


Fog is a visible aerosol consisting of tiny water droplets or ice crystals suspended in the air at or near the Earth's surface. Fog can be considered a type of low-lying cloud, usually resembling stratus, and is heavily influenced by nearby bodies of water, topography, and wind conditions. In turn, fog has affected many human activities, such as shipping, travel, and warfare.


Graupel (German pronunciation: [ˈɡʁaʊpəl]; Enɡlish: [ˈgɹaʊpəl]), also called soft hail or snow pellets, is precipitation that forms when supercooled water droplets are collected and freeze on falling snowflakes, forming 2–5 mm (0.08–0.20 in) balls of rime. The term graupel comes from the German language.

Graupel is distinct from hail, small hail and ice pellets: the World Meteorological Organization defines small hail as snow pellets encapsulated by ice, a precipitation halfway between snow pellets and hail. Small hail is common in thunderstorms, while graupel typically falls in winter storms. The METAR code for graupel is GS.


Ha'il (Arabic: حَائِل‎ Ḥā'il) is a city in north-western Saudi Arabia. It is the capital of Ha'il Region, and has a population of about 1,200,000.

Ha'il is largely agricultural, with significant grain, date, and fruit production. A large percentage of the kingdom's wheat production comes from Ha'il Region, where the area to the northeast, 60 to 100 km (37 to 62 miles) away, consists of irrigated gardens. Historically, Ha'il derived its wealth from being on the camel caravan route of the Hajj. Ha'il is well known by the generosity of its people in Saudi Arabia and the Arab world as it is the place where Hatim al-Tai lived. It is also the homeland of the Rashid royal family, historical rivals to Saudi royal family.

Hail, Caesar!

Hail, Caesar! is a 2016 comedy film written, produced, edited, and directed by Joel and Ethan Coen. The film stars Josh Brolin, George Clooney, Alden Ehrenreich, Ralph Fiennes, Jonah Hill, Scarlett Johansson, Frances McDormand, Tilda Swinton, and Channing Tatum. It is a fictional story that follows the real-life fixer Eddie Mannix (Brolin) working in the Hollywood film industry in the 1950s, trying to discover what happened to a cast member who vanished during the filming of a biblical epic.

First talked about by the Coens in 2004, Hail, Caesar! was originally set to take place in the 1920s and to follow actors performing a play about ancient Rome. The Coens shelved the idea until late 2013. Principal photography began in November 2014 in Los Angeles, California.

The film premiered in Los Angeles on February 1, 2016, and was released in the United States on February 5, 2016. It grossed $63 million worldwide and received positive reviews. The film was chosen by National Board of Review as one of the top ten films of 2016 and it received nominations at the 89th Academy Awards and 70th British Academy Film Awards, both for production design.

Hail Mary

The Hail Mary (Latin: Ave Maria) is a traditional Catholic prayer asking for the intercession of the Blessed Virgin Mary, the mother of Jesus. In Roman Catholicism, the prayer forms the basis of the Rosary and the Angelus prayers. In the Oriental Orthodox Churches, Eastern Orthodox and Eastern Catholic Churches, a similar prayer is used in formal liturgies, both in Greek and in translations. It is also used by many other groups within the catholic tradition of Christianity including Anglicans, Independent Catholics, and Old Catholics.

Largely based on two phrases in the Gospel of Luke, the prayer takes different forms in various traditions. It has often been set to music.

Hail Mary (2Pac song)

"Hail Mary" is a single by American rapper Tupac Shakur from his final album The Don Killuminati: The 7 Day Theory, under the new stage name, Makaveli. The song, released after his September 1996 death, features rap verses by Kastro, Young Noble and Yaki Kadafi of The Outlawz and Prince Ital Joe. A music video was shot for the song and can be found on the DualDisc of The Don Killuminati: The 7 Day Theory. It is one of Shakur's most famous singles. The single peaked at number 12 in the R&B chart, and number 8 in the rap singles.

The song captures Makaveli zoning out the violence and negativity surrounding him, praying to God, and making biblical references. "Hail Mary" appeared on Shakur's Greatest Hits in 1998. A remix of the song was also featured on the album Nu-Mixx Klazics in 2003.

Hail Mary pass

A Hail Mary pass, also known as a shot play, is a very long forward pass in American football, typically made in desperation, with only a small chance of success and/or time running out on the clock. The term became widespread after a December 28, 1975 NFL playoff game between the Dallas Cowboys and the Minnesota Vikings, when Cowboys quarterback Roger Staubach (a Roman Catholic and fan of The Godfather Part II (1974), whose character Fredo had popularized the phrase) said about his game-winning touchdown pass to wide receiver Drew Pearson, "I closed my eyes and said a Hail Mary."The expression goes back at least to the 1930s, in which decade it was widely used publicly by two former members of Notre Dame's Four Horsemen, Elmer Layden and Jim Crowley. Originally meaning any sort of desperation play, a "Hail Mary" gradually came to denote a long, low-probability pass, typically of the "alley-oop" variety, attempted at the end of a half when a team is too far from the end zone to execute a more conventional play, implying that it would take divine intervention for the play to succeed. For more than 40 years, use of the term was largely confined to Notre Dame and other Catholic universities.

Hail To Reason

Hail To Reason (April 18, 1958 – February 24, 1976) was an American thoroughbred racehorse and an influential sire.

Hail to the Chief

"Hail to the Chief" is the official Presidential Anthem of the United States, composed by James Sanderson. The song's playing accompanies the appearance of the President of the United States at many public events, it is also played at inauguration ceremonies. For major official occasions, the United States Marine Band and other military ensembles are generally the performers, so directives of the United States Department of Defense have, since 1954, been the main basis for according it official status. It is preceded by four ruffles and flourishes when played for the President. The song is also played during a former President's state funeral after the casket is removed from the hearse. As it originated from the 19th century, the song is in the public domain due to its age.

Hail to the Thief

Hail to the Thief is the sixth studio album by the English rock band Radiohead. It was released on 9 June 2003 by Parlophone in the UK and a day later by Capitol Records in the United States. It was the last album released under Radiohead's record contract with EMI.

After transitioning to a more electronic style on their albums Kid A (2000) and Amnesiac (2001), recorded through protracted studio experimentation, Radiohead sought to combine electronic and rock music. They recorded most of Hail to the Thief in two weeks in Los Angeles with longtime Radiohead producer Nigel Godrich, focusing on live takes rather than overdubs. Songwriter Thom Yorke wrote many of the lyrics in response to the War on Terror and the resurgence of right-wing politics in the west. The cover artwork, created by longtime Radiohead artist Stanley Donwood, is a roadmap of Hollywood with words taken from roadside advertising in Los Angeles and from Yorke's lyrics.

Despite a high-profile internet leak of unfinished material ten weeks before release, Hail to the Thief debuted at number one on the UK Albums Chart and number three on the US Billboard 200 chart, and was certified platinum in the UK, US and Canada. It produced three charting singles: "There There", "Go to Sleep" and "2 + 2 = 5". The album received mostly positive reviews and was the fifth consecutive Radiohead album nominated for a Grammy Award for Best Alternative Music Album.

Nazi salute

The Nazi salute, Hitler salute (German: Hitlergruß, lit. 'Hitler Greeting', IPA: [ˈhɪtlɐˌɡʁuːs], also German: deutscher Gruß, lit. 'German Greeting'), or Sieg Heil salute, is a gesture that was used as a greeting in Nazi Germany. The salute is performed by extending the right arm from the neck into the air with a straightened hand. Usually, the person offering the salute would say "Heil Hitler!" (Hail Hitler!), "Heil, mein Führer!" (Hail, my leader!), or "Sieg Heil!" (Hail victory!). It was adopted in the 1930s by the Nazi Party to signal obedience to the party's leader, Adolf Hitler, and to glorify the German nation (and later the German war effort). The salute was mandatory for civilians but mostly optional for military personnel, who retained the traditional military salute until the failed assassination attempt on Hitler on 20 July 1944.

Use of this salute is illegal in modern Germany and Austria (Verbotsgesetz 1947), and is also considered a criminal offense in modern Poland, Slovakia, and Austria. In Canada, the Czech Republic, France, the Kingdom of the Netherlands, Sweden, Switzerland, and Russia, displaying the salute is not in itself a criminal offence, but constitutes illegal hate speech if used for propagating Nazi ideology.

Salve Regina

The Salve Regina (; Ecclesiastical Latin: [ˈsalve reˈdʒina], meaning "Hail Queen"), also known as the Hail Holy Queen, is a Marian hymn and one of four Marian antiphons sung at different seasons within the Christian liturgical calendar of the Catholic Church. The Salve Regina is traditionally sung at Compline in the time from the Saturday before Trinity Sunday until the Friday before the first Sunday of Advent. The Hail Holy Queen is also the final prayer of the Rosary.

The work was composed during the Middle Ages and originally appeared in Latin, the prevalent language of Western Christianity until modern times. Though traditionally ascribed to the eleventh-century German monk Hermann of Reichenau, it is regarded as anonymous by most musicologists. Traditionally it has been sung in Latin, though many translations exist. These are often used as spoken prayers.


A thunderstorm, also known as an electrical storm or a lightning storm, is a storm characterized by the presence of lightning and its acoustic effect on the Earth's atmosphere, known as thunder. Relatively weak thunderstorms are sometimes called thundershowers. Thunderstorms occur in a type of cloud known as a cumulonimbus. They are usually accompanied by strong winds, and often produce heavy rain and sometimes snow, sleet, or hail, but some thunderstorms produce little precipitation or no precipitation at all. Thunderstorms may line up in a series or become a rainband, known as a squall line. Strong or severe thunderstorms include some of the most dangerous weather phenomena, including large hail, strong winds, and tornadoes. Some of the most persistent severe thunderstorms, known as supercells, rotate as do cyclones. While most thunderstorms move with the mean wind flow through the layer of the troposphere that they occupy, vertical wind shear sometimes causes a deviation in their course at a right angle to the wind shear direction.

Thunderstorms result from the rapid upward movement of warm, moist air, sometimes along a front. As the warm, moist air moves upward, it cools, condenses, and forms a cumulonimbus cloud that can reach heights of over 20 kilometres (12 mi). As the rising air reaches its dew point temperature, water vapor condenses into water droplets or ice, reducing pressure locally within the thunderstorm cell. Any precipitation falls the long distance through the clouds towards the Earth's surface. As the droplets fall, they collide with other droplets and become larger. The falling droplets create a downdraft as it pulls cold air with it, and this cold air spreads out at the Earth's surface, occasionally causing strong winds that are commonly associated with thunderstorms.

Thunderstorms can form and develop in any geographic location but most frequently within the mid-latitude, where warm, moist air from tropical latitudes collides with cooler air from polar latitudes. Thunderstorms are responsible for the development and formation of many severe weather phenomena. Thunderstorms, and the phenomena that occur along with them, pose great hazards. Damage that results from thunderstorms is mainly inflicted by downburst winds, large hailstones, and flash flooding caused by heavy precipitation. Stronger thunderstorm cells are capable of producing tornadoes and waterspouts.

There are four types of thunderstorms: single-cell, multi-cell cluster, multi-cell lines and supercells. Supercell thunderstorms are the strongest and most severe. Mesoscale convective systems formed by favorable vertical wind shear within the tropics and subtropics can be responsible for the development of hurricanes. Dry thunderstorms, with no precipitation, can cause the outbreak of wildfires from the heat generated from the cloud-to-ground lightning that accompanies them. Several means are used to study thunderstorms: weather radar, weather stations, and video photography. Past civilizations held various myths concerning thunderstorms and their development as late as the 18th century. Beyond the Earth's atmosphere, thunderstorms have also been observed on the planets of Jupiter, Saturn, Neptune, and, probably, Venus.


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