JUST HALFWAY through the summer of 2021, a startling record was set: By one measure, almost 100 percent of the Western U.S. was in drought. In 122 years of observation, never had that much land been that dry west of the Continental Divide. Lack of precipitation was a factor. But even more significant were high temperatures. In June alone, 202 all-time record highs were set in the West. For the Southwest, these extremes amplified a 20-year megadrought that's been drying out the region and, most notably, the Colorado River Basin. In the effort to meet rising water demands in the basin, the two largest reservoirs in the U.S. - lakes Mead and Powell along the Colorado River - both shriveled to historic lows this summer. "It's a ticking time bomb," says Brad Udall, a water and climate research scientist at Colorado State University.
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