The United States is in the midst of one of the biggest droughts in recent memory. At last count, over half of the lower 48 states had abnormally dry conditions and are suffering from at least moderate drought.

More than 80% of seven states were as of last week in “severe drought,” characterized by crop or pasture loss, water shortage and water restrictions. Depending on whether the hardest-hit regions see significant precipitation, crops yields could fall and drought conditions could persist for months to come. Based on the latest data provided by the U.S. Drought Monitor, 24/7 Wall St. reviewed the seven states running out of water.

Click here to see the seven states running out of water

U.S. Department of Agriculture meteorologist and Drought Monitor team member, Brad Rippey, explained that when the drought began in 2012, the worst of the conditions were much farther east, in states like Indiana, Ohio, and Michigan — the corn belt states. Based on pre-drought estimates, corn used for grain lost slightly more than a quarter of its potential. By the Summer of 2012, 59% of U.S. rangeland and pastureland was rated by the USDA as being in poor or very poor condition. The growing drought decimated national hay production, causing feed shortages, which in turn drove up prices in livestock.

By the fall of 2012, drought conditions continued to expand westward to its current epicenter — states like Nebraska, Kansas, Colorado and Oklahoma. Rippey explained that most worrying is the drought’s effects on the winter wheat crop, which is one of the biggest crops grown in the U.S., and which is grown almost entirely in the states in severe drought. While the region has had some precipitation recently, “winter wheat crop will need ideal conditions heading through the next few weeks just to break even. We’re still trending towards a very poor hard red winter wheat crop at this point,” Rippey said.

In addition to severe drought conditions, relatively large areas in the worst-off states are in “exceptional” drought, which the USDA identifies as “exceptional and widespread crop/pasture losses, shortages of water in reservoirs, streams, and wells creating water emergencies.” More than 70% of Nebraska is currently classified as being in a state of “exceptional drought,” which includes Exceptional and widespread crop/pasture losses; shortages of water in reservoirs, streams, and wells creating water emergencies.

The last time the U.S. saw a drought close to this level of severity was in the 1980s, Rippey explained. But even compared to that drought, the current conditions may be worse. “You really need to go back to the 1950s to find a drought that lasted and occupied at least as much territory,” Rippey said.

The U.S. Drought Monitor, is produced by the National Drought Mitigation Center at the University of Nebraska-Lincoln, the United States Department of Agriculture (USDA), and the National Oceanic and Atmospheric Administration (NOAA). 24/7 Wall St. reviewed the seven states that had at least 80% of the total area classified in at least a state of severe drought as of March 14th. We also reviewed agricultural statistics, such as crop yields, in these states, using data collected from USDA state agricultural overviews. Most of these data are for 2011.