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The North American Drought of 1988 ranks among the worst episodes of drought in the United States. This multi-year drought began in most areas in 1988 and continued into 1989. The drought caused $60 billion (1988 United States dollars) in damage ($120 billion in 2014 United States dollars, adjusting for inflation). The drought occasioned some of the worst blowing-dust events since 1977 or the 1930s in many locations in the Midwestern United States, including a protracted dust storm, which closed schools in South Dakota in late February 1988. During the spring, several weather stations set records for lowest monthly total precipitation and longest interval between measurable precipitation, for example, 55 days in a row without precipitation in Milwaukee. During the summer, two record-setting heat waves developed, similar to those of 1934 and 1936. The concurrent heat waves killed 4,800 to 17,000 people in the United States. During the summer of 1988, the drought led to many wildfires in forested western North America, including the Yellowstone fires of 1988. At its peak, the drought covered 45% of the United States. While covering less area than the Dust Bowl, which covered 70% of the United States, the drought of 1988 ranks as not only the costliest drought in United States history but also the costliest natural disaster in United States history before Hurricane Katrina. In Canada, drought-related losses added to $1.8 billion (1988 Canadian dollars). ==Origin== The Western United States experienced a lengthy drought in the late 1980s. Much of California endured one of its longest droughts ever observed from late 1986 through early 1991. Drought worsened in 1988 as much of the United States also suffered from severe drought. In California, the five-year drought ended in late 1991 as a significant El Niño event in the Pacific Ocean (and the eruption of Mount Pinatubo in June 1991) most likely caused unusual persistent heavy rains. Following a milder drought in the Southeastern United States and California in 1987, this drought overspread the Mid-Atlantic states, Southeastern United States, Midwestern United States, northern Great Plains, and Western United States. Heat waves accompanied this widespread, unusually intense drought and killed around 4,800 to 17,000 Americans. The heat also killed livestock across the United States. Farmers perhaps cultivated marginally arable land, contributing to the damage from this drought. Pumping groundwater near depletion also contributed to damage. The drought destroyed crops almost nationwide; lawns of residents went brown, and many cities declared water restrictions. Hurricane Gilbert, which crossed into Texas and the Great Plains as a tropical storm then tropical depression and then remnants thereof much further north was very helpful in some areas, bringing more than four inches (100 mm) of rain to parts of the Middle West;〔Weatherwise, January 1989: "The Weather of 1988"〕 in some areas it was an outright drought-buster, but other locations were at -6 or lower on the Palmer Drought Severity Index by early autumn 1988 and a general change in the pattern which had held for nine or more months at that point was required to resolve the hydrological impacts of the drought. The agricultural damage was essentially done by this point, resulting in prices for commodities which reached records at the time and frequently were up the limit on commodities exchanges. Wildfires in Yellowstone National Park burned many trees and created exceptional destruction in the area. This very catastrophic drought for multiple reasons continued across the Upper Midwest and northern Great Plains states during 1989, not officially ending until 1990. The conditions continued into 1989 and 1990, although the drought ended in some states, thanks to normal rainfalls returning to some portions of the United States. Dry conditions, however, increased again during 1989, affecting Iowa, Missouri, eastern Nebraska, Kansas and certain portions of Colorado. The drought also affected Canada in certain divisions. The persistent wind pattern brought hot dry air into the middle of the continent from the desert south-west day after day and week after week starting during the spring, whereas in most years advection of warm and humid air from the Gulf of Mexico is the rule; therefore despite the extremely high actual temperatures, elevation of apparent temperature was not as severe as had been the case duing the 1995 heat wave which involved heat indices in excess of 150 °F/65 °C due to dew points as high as 90 °F/32 °C. None the less, the almost nationwide persistent, multi-phase 1936-style heat waves did kill many people (see above). The lower than average relative humidity which was a cause and effect of the drought contributed to grass and forest fires in the Middle West and further east and not only combined with cloudless skies day after day and a huge stretch of dry, hot, exposed top soil to generate the heat waves during the summer but, as was the case in past droughts of the type as well as 2012, a widening of the diurnal temperature range brought infrequent but consistent cold nights throughout the spring, summer, and autumn, including light frost in northern parts of the region well into June and measurable snow and sleet in May in some locations.〔Weatherwise, January 1989〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「1988–89 North American drought」の詳細全文を読む スポンサード リンク
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