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A winch and a crane keep a dredging apparatus steady as it sucks up sand from the bottom of a navigation channel on the Mississippi River on Monday, Aug. 20, 2012 near Memphis, Tenn. The Mississippi River from Illinois to Louisiana has seen water levels plummet due to drought conditions in the past three months. Near Memphis, the river level was more than 12 feet lower than normal for this time of year. (AP Photo/Adrian Sainz)

U.S. drought crisis

Triple-digit temperatures and weeks without rain withered and destroyed many crops in the Midwest, sending commodity soybean and grain prices soaring in 2012.