"Drought is a natural hazard, often with significant societal, economic, and environmental consequences. Public policy issues related to drought range from how to identify and measure drought to how best to prepare for, mitigate, and respond to drought impacts, and who should bear associated costs. Severe droughts in 2011 and 2012 in Texas and the midcontinent region, and the current drought in California and the American Southwest, have fueled congressional interest in drought and its near-term effects on water supplies and agriculture, as well as interest in long-term issues, such as drought forecasting and links between drought and human-induced climate change. Continuing drought conditions throughout the country contribute to ongoing interest in drought. Some part of the country is almost always experiencing drought at some level. Since 2000, no less than 6.6% of the land area of the United States has experienced drought of at least moderate intensity each year. The land area affected by drought of at least moderate intensity varies by year and also within a particular year. For example, since 2000, the total U.S. land area affected by drought of at least moderate intensity has varied from as little as 6.6% (July 6, 2010) to as much as 55% (September 25, 2012). Based on weekly estimates of the areal extent of drought conditions since 2000, the average amount of land area across the United States affected by at least moderate-intensity drought has been 27%."
CRS Report for Congress, R43407
Federation of American Scientists: http://www.fas.org/sgp/crs/index.html