Drought persists in Southwest, relief in Northwest

La Niña has returned for a second consecutive winter, leading to concerns that drought will persist or further intensify across the nation’s southwestern quadrant, extending as far east as the southern Great Plains.  The prospect of ongoing Southwestern drought has implications for the region’s supply of surface water, which has dwindled in recent years amid a changing climate regime that has featured warmer, drier weather since the beginning of the 21st century.  Even with a burst of late-October storminess in northern and central California, the Golden State gained less than 0.7 million acre-feet of water in its 154 primary intrastate reservoirs during the month ending Oct. 31 — a small boost in statewide storage from 12.6 to 13.3 million acre-feet, which is still less than two-thirds of average for this time of year.

Meanwhile, La Niña’s return brings the promise of drought relief in the Northwest. Indeed, heavy precipitation has already occurred across the Pacific Northwest, leading to drought eradication west of the northern Cascades and even some pockets of flooding.  For the remainder of the winter in 2022, further improvement in the drought situation can be expected from the northern Pacific Coast to the northern Rockies.  Areas of the upper Midwest experiencing lingering drought impacts may also continue to receive significant precipitation, including periods of wind-driven snow.

Even with drought’s footprint shrinking across the northern United States, national coverage remains at historically high levels.  In fact, drought coverage in the lower 48 states has continuously exceeded 40% for more than a year, according to the U.S. Drought Monitor — only the third such occurrence of this century, along with 2002-03 and 2012-13.  One impact of ongoing drought can be seen in the condition of the recently planted 2021-22 winter wheat crop.  In mid-November, one-fifth of the U.S. winter wheat was rated in very poor to poor condition, according to the U.S. Department of Agriculture, with statewide values greater than 25% in six major production states across the Plains and Northwest.