HailTan

Hail
Alex S. & Michael Z.Tan Class Introduction  The clouds darken the sky, the area chills. Chunks of ice fly from the sky smashing into everything, killing crops, denting cars, and possibly causing death. (1) The storm ends. What is it? It is HAIL! Oftenly coexisting with rain or snow, hail is a large frozen raindrop produced by fierce thunderstorms that grows in size from collisions with supercooled water. (8)



Dangers Hail can be very dangerous. Hailstones three quarter of an inch or larger (penny size) are considered big enough to cause serious injury or damage (ten to fifteen percent of the hailstorms in the U.S.) (2) (Visit [|Hail Size Estimation] for information on estimating hail size. ) The worst hail storms have hail big enough to kill people, smash through roofs, damage entire fields of crops, destroy air plane windshields, destroy cars, and cause hundred of millions of dollars in repairs. (1) The stronger the updraft, the larger the hailstone may grow. (1) As they fall towards the ground, the speed of impact is usually related to the size of the hailstone. (1,2) In a hailstorm in Nebraska, hailstones 4-5 feet in diameter ended up completely buried in the ground when found. (1) During a severe hailstorm in Missouri, hail with 4 inches in diameter (grapefruit sized) crashed through the roofs of houses. (1) Crops are greatly damaged by hail. (1) Hailstorms in Iowa have done severe enough damage to corn fields to cause farmers to look for jobs elsewhere. (1) Today hail annually destroys at least one million dollars in crops in the United States. (1) The cloud that has a possibility to for hail formation is also dangerous to planes and animals flying through it. The strong updrafts and downdrafts cause extreme turbulence while the supercooled droplets of air can collide into objects, freeze, and incase them in ice. (1)





Conditions of Formation Hail usually occurs where there is an area of lifting. (1) Often times this happens between the latitudes between 30 and 50, the polar front, where cold air from the the poles meet the warm air from the equator leading to convection. (1) Other times hail is likely to occur is on high terrain, where orographic lifting will cause the lifting of air, or locations with unstable air, since they generate powerful updrafts. (1,2,3) Now there are strong updrafts of warm air since the convergence of warm tropical air and cold polar air will result in the warm air being lifted. (2) The warm air rises and loses all its heat from the diffusion of heat from the air surrounding it and adiabatic cooling. In addition the moisture will leave the air when the air cools to reach its dew point, it will soon become a downdraft of cold air since it is now more dense then the surrounding air. (3) Also under these conditions of lifting, large cumulonimbus clouds may develop. (2) When the air reaches its due point, water vapor will condense forming water droplets. When a water droplet is picked up by one of the updrafts, it will be carried into a cooler part of the atmosphere where the droplet will freeze. (2) As the frozen droplet falls or gets carried away by a downdraft, it may begin to thaw as the air becomes warmer at the bottom part of the thunderstorm or it may stay in the form of an ice crystal. (2) Either way, it will be carried up by an updraft back into the freezing part of the cloud, where it will refreeze if it melted. On its way up and down, it will collide with supercooled water droplets, which freeze when hitting the ice. This will cause the formation of a layer of ice around the original piece. (1,2,3,9) Soon it'll start its journey down again, get lifted, collide with more supercooled water droplets, and then freeze another coating of ice. The ice keeps circulating with updrafts, gravity, and downdrafts, growing in size. (2,9) The ice keeps doing this until the updraft can no longer bring it up, due to its size or a powerful downdraft bringing it down. (1,2,9) Finally, the frozen-rain-droplet-ball falls to to ground as hail. (2) Water droplets aren't the only things that hail can be made of. When winds reach above 100mph, they may pick up leaves, sticks, nuts, small stones, insects, and even small animals and fish. (1) If they are blown high enough and cross the freezing level, they will collide with the supercooled water droplets and become the center of a hailstone. (1)



Historical Examples The deadliest hailstorm occured on April 30, 1888 in India's Moradad and Bareilly districts in India. (1) It had killed 246 people, either hit by enormous pieces of hail or being hit by hail, knocked back, and burried by the hail. (1) The hailstorm also killed 1600 farm animals. (1) The hailstorm hitting Kansas City on April 1, 2001, was the most costly one resulting in about 2 billion dollars in damage. (2) The heaviest piece of hail that fell was in Coffeyville, Kansas on September 3, 1970. (1,2,3) It weighed 1.67 pounds. (1,2,3) The largest hailstone fell in Aurora, Nebraska in a hailstorm on June 23, 2003. (2) It had a diameter of seven inches and a circumference of 18.75 inches. (2) Hail has also played a role in history. On April 13, 1360 (May 8 in other sources), in the middle of the 100 years war between England and France, "Black Monday" one of the most deadly hailstorms in history. It killed 1,000 English troops in Chartres, France. (11,1) The tragic and monumental losses that were suffered by the English on that day were seen by many people as a sign from G-D. (11). Immediately after, the English king seeked peace resulting in the treaty of Bretigny. (1)



Safety How to protect yourself from a hailstorm depends on your location. Generally, stay away from the windows incase hail breaks through them, don't use electronics (ex: cellphones) to prevent electrocution from lightning, cover your eyes, and if in a house or a car, don't go outside. While in a car, the optimum position to be is away from the windows, lying facedown on the floor. If possible, find a location under a sturdy structure and stop driving. Make sure you do not drive into deep hail (hail that has accumulated over 1 foot) because it can sweep the car away. (5,6) If you're inside a house, avoid windows that hail is hitting, and don't go into a basement because hail sometimes may enter and bury anything there. (4,5,6) With the chance you're outside during a hailstorm, try to find shelter quickly. If nothing can be found, hide under something to protect you're head. Remember that trees are a last resort since they attract lightning and lose branches (5,6). Make sure to stay in the safe location until the storm has subsided (5,6) (usually lasting a few minutes). (1) Studies have occurred about hail prevention/suppression, read: [|Weather Prevention/Modification].



Sources

1. Hughes, Patrick, and Richard Wood. "Hail: the white plague." //Weatherwise// Apr.-May 1993: 16+. //Gale Science In Context//. Web. 26 Nov. 2010 <[|http://ic.galegroup.com.welproxy.minlib.net/ic/scic/AcademicJournalsDetailsPage/AcademicJournalsDetailsWindow?displayGroupName=Journals&prodId=SCIC&action=e&windowstate=normal&catId=&documentId=GALE|A13997920&mode=view]>. 2. Hail...Damage to property and crops.... National Weather Service. 5 May. 2010. Web. 28 Nov. 2010. <@http://www.erh.noaa.gov/er/cae/svrwx/hail.htm>. 3. Tarbuck, Edward J., and Frederick K. Lutgens. //Earth Science//. Boston: Pearson Prentice Hall, 2009. 514-522. Print. 4. Nelson, Libby. "Winter, Like Guest Uninvited, Drops In." //The New York Times// 9 July 2009: n. pag. Web. 1 Dec. 2010. 5. Weaver, John and Nolan Doesken. "Hail Safety Tips." City of Fort Collinis Office of Emergency Management. Web. 26 Nov. 2010. <@http://www.fcgov.com/oem/pdf/hail-brochure.pdf>. 6. "Hail Safety." //Hail Safety//. Cass County Sheriff's Office, 2006. Web. 28 Nov. 2010. <@http://www.cassmosheriff.org/msg_hail.aspx>. 7. "Hail ." //Storm Encyclopedia//. The Weather Channel Interactive, 2010. Web. 28 Nov. 2010. <@http://www.weather.com/encyclopedia/thunder/hail.html>. 8. "Rain and Hail Liquid and Ice Precipitation." //Rain and Hail Liquid and Ice// //Precipitation//. University of Illinois, n.d. Web. 27 Nov. 2010. . 9. "Examine an animation of hail forming." //Examine an animation of hail forming//. McDougal LIttell, National Science Foundation, TERC, n.d. Web. 29 Nov. 2010. <[]>. <span style="font-family: Arial,sans-serif;">10. Painter, Adam. "Research Looking For Bacteria In Hail." NBC Montana. 9 Nov. 2010. Web 3 Dec. 2010 @http://www.nbcmontana.com/news/25690420/detail.html <span style="font-family: Arial,sans-serif;">11. "Hail Kills English Troops" This Day In History: 13 April. 3 Dec. 2010. @http://www.history.com/this-day-in-history/hail-kills-english-troops