Surface soils and plants aren't the only things affected by drought. Groundwater also can get seriously depleted, leading to significant impacts on uses such as drinking water, irrigation, industries, and aquifer recharge.

To see how the groundwater is faring in your area, check out NASA's groundwater maps, updated weekly. At the moment, some of the biggest problem areas are throughout much of the southern half of the country, in many areas in the northwest quadrant of the country, and much of Michigan.

Excess groundwater can contribute to problems such as flooding. Among the most groundwater-abundant areas at the moment are much of the northern half of the Great Plains, many areas in California, Nevada, and Utah, portions of eastern Oregon and Washington and western Idaho, and much of the Northeast.

• National Drought Mitigation Center, "Groundwater and Soil Moisture Conditions from GRACE Data Assimilation" [2]; Nov. 30, 2011, press release. [3]

To keep up to speed on surface drought conditions (which can vary substantially from groundwater drought conditions), see:

• US Drought Monitor. [4]