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2024 Hennepin County All -Jurisdiction Hazard Mitigation Plan <br />Volume 2 — Hazard Inventory <br />�Hazard Assessment: HAIL <br />4.3.4.1. Definition <br />Hail is precipitation that is <br />formed when updrafts in <br />thunderstorms carry raindrops <br />upward into extremely cold <br />areas of the thunderstorm where <br />they are continuously lofted and <br />form into hail. They eventually <br />become heavy and fall to the <br />ground. Hail can cause billions of <br />dollars of damage to structures, <br />cars, aircraft, and crops, and can <br />be deadly to livestock and <br />people. <br />Damaging hail is associated with <br />severe thunderstorms, and is <br />often found in proximity to <br />strong winds, torrential rainfall, <br />and even tornadoes. <br />Large hail, source NSSL (http://www.nssi.noaa.gov/education/svrwxl0l/hail/) <br />Supercell thunderstorms are responsible for most Minnesota hail reports more than 1.5 inches in <br />diameter, and nearly all reports in excess of 2.5 inches. These supercell thunderstorms may or may not be <br />tornadic at the time of hail production. Damage becomes significantly more likely as hail size increases <br />because the impact factor increases exponentially with incremental growth (Table 4.3.4A). <br />Table 4.3.4A Hail diameter and impact. From Marshall et al. (2001). <br />.................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................. <br />Haii Diameter <br />1„ <br />211 <br />311 <br />Impact (foot-ibs) <br /><1 <br />22 <br />120 <br />4.3.4.2. Range of magnitude <br />Largest hail stones reported. <br />• Hennepin: <br />0 3-inch diameter, Minneapolis, August 11, 2023 <br />0 3-inch diameter, Independence, August 5, 2019 <br />0 4-inch diameter, Bloomington, Richfield, South Minneapolis, July 8, 1966 <br />• Adjacent counties: <br />0 4-inch diameter, Delano, Wright County, August 5, 2019 <br />0 4.25-inch diameter, New Prague, Scott County, August 24, 2006 <br />95 <br />