About 40 percent of the contiguous United States is currently parched by a rainfall shortage. July has seen the highest percentage of the United States in drought conditions ever recorded by the U.S. Drought Monitor, said Brian Fuchs of the National Drought Mitigation Center at the University of Nebraska-Lincoln in a press release.

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The Monitor ranks conditions from D0 (abnormal dryness) and moves up in severity to D1 (moderate drought), D2 (severe drought), D3 (extreme drought) and D4 (exceptional drought). Although several whole states are in a drought, certain areas areas are further behind in the amount of rain that has fallen. The ranking system helps people understand how fierce the drought is in one area relative to another.

Texas is the hardest hit. Three-fourths of the state broils under “exceptional drought” conditions. But many other states are suffering as well.

• New Mexico – 100 percent of the state is in a drought; 48 percent of the state suffers under D4 (exceptional drought) conditions.
• Louisiana – 100 percent drought; 33 percent exceptional
• Oklahoma – 100 percent drought; 52 percent exceptional
• South Carolina – 97 percent drought; 16 percent exceptional
• Georgia – 95 percent drought; 68 percent exceptional
• Arkansas – 96 percent drought; 6 percent exceptional
• Florida – 89 percent drought; 20 percent exceptional

Altogether, 18 percent of the United States is in an extreme or exceptional drought, according to the Drought Monitor’s rating system.

The Drought Monitor has only been in existence for 12 years, but it uses a wealth of numerical data and researchers expertise to map out parched patches of the United States. Over 300 climatologists, extension agents and others contribute data and analysis to the Monitor. The Monitor is maintained by the National Drought Mitigation Center and the National Oceanic and Atmospheric Administration.

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Help may be on the horizon for some areas. Within the next few weeks Tropical Storm Don could bring rain and relief to the central and western Gulf Coast states, but it might not be enough.

“Whenever there is a lot of moisture in a short period of time, the potential exists for rapid improvement,” Fuchs said. “But while that possibility exists, it won’t necessarily mean the end of drought in those areas. It will likely only improve by one drought category for those areas not impacted by any tropical storms or where drought related impacts improve.”

IMAGE 1: Latest map of drought conditions. (U.S. Drought Monitor)

IMAGE 2: Parched cornfields in Castroville, Texas, on June 19, 2011. (Wikimedia Commons)

IMAGE 3: Animation of last 12 weeks of drought conditions. (U.S. Drought Monitor)