U.S. Drought Monitor

 (data through 1/18/11)
Data Source(s): U.S. Department of Agriculture, National Drought Mitigation Center, National Oceanic and Atmospheric Administration

An active winter storm pattern dominated much of the western U.S. over the past 30 days, bringing average to above-average precipitation to almost all areas except southern Arizona and most of New Mexico. This has kept much of the western U.S. drought free and has even beaten back some short-term drought conditions that were present in Nevada and northwestern Arizona in mid-December (Figure 3). Often called Pineapple Express storms, several unusually strong storms in middle to late December tapped moisture from the tropical Pacific Ocean and dropped copious amounts of precipitation across Southern California, southern Nevada, and northwestern Arizona. The 30-day precipitation totals are in excess of 400 percent of average in some of these regions. Overall, only 23 percent of the area in the western U.S. is experiencing abnormally dry conditions or worse. In the Southwest, moderate to severe conditions are being experienced in southern Arizona, New Mexico and eastern Colorado.

Notes: