Farmer Aries Haygood shows how powdery the top layer of soil is on his freshly planted Vidalia onion farm in Lyons, Ga., on Dec. 10, 2010. The nation's extreme weather — flood-inducing downpours, extended droughts, heat waves and bitter cold and snow — has doubled in the 30 years since 1988, according to a federal index.  (David Goldman/AP)
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