United States: Water deficits in the West will shrink

United States: Water deficits in the West will shrink

21 October 2021

THE BIG PICTURE
The 12-month forecast ending June 2022 indicates water deficits of varying intensity in the U.S. West, Pacific Northwest, and parts of the Rockies and Upper Midwest. Areas where deficits will be exceptional include Spokane, Washington through the Salmon River region in Idaho; the Willamette Valley in Oregon; and northern California’s border region.

North Dakota can expect deficits throughout much of its extent, more intense in the east, and severe to exceptional deficits are forecast in Minnesota’s northern half, moderating in the south. The intensity of deficits will pick up again in central Iowa reaching east through the Wisconsin/Illinois border area. Surpluses are forecast in southeastern Michigan and a few pockets in central Wisconsin and near the source of the Red River in South Dakota.

In the U.S. Northeast, surpluses, primarily moderate, will reach through much of New York into nearby eastern regions to the Atlantic. Deficits are forecast along the St. Lawrence River in New York and will extend through northern Vermont and New Hampshire and western Maine. Anomalies will be exceptional around Lake Champlain. Some pockets of deficit are forecast in Virginia and deficits will span the border of the Carolinas, reaching the coast. In Peninsular Florida, deficits will be widespread and will include exceptional anomalies near Lake George in the north and Lake Okeechobee in the south.

In the Gulf States, surpluses, including intense anomalies, are expected in southeastern Louisiana and southern Mississippi reaching into Alabama to the Tombigbee River. To the north, moderate surpluses are forecast in central Tennessee. In Texas, the Corpus Christi metropolitan area can expect surpluses while moderate deficits will follow the Rio Grande on either side of Amistad Reservoir.

Outside the contiguous U.S., Alaska can expect intense deficits in the northeast and near Anchorage and Valdez in the south. Areas of surplus include the central Arctic Coast east of Barrow, Noatak National Preserve, and the eastern reaches of the Alaska Range. Surpluses are expected in Hawaii, and moderate to severe deficits in Puerto Rico.

FORECAST BREAKDOWN
The 3-month maps (below) show the evolving conditions in more detail.

The forecast through December indicates that anomalies will shrink considerably. Deficits will persist in the Rockies, Oregon, and on the Missouri River. Moderate to severe deficits are forecast in Minnesota, Iowa, Wisconsin, northern Illinois, and Michigan’s Upper Peninsula. Surpluses are expected in southeastern Michigan, northeastern Indiana, northern Ohio, and southern Indiana and Illinois. Moderate surpluses will linger in the Susquehanna River Watershed in Pennsylvania, the Finger Lakes Region of New York, and pockets reaching to the Atlantic. Deficits will persist on the St. Lawrence River, around Lake Champlain, and west of Moosehead Lake, Maine. Deficits are also forecast from Delaware through the Carolinas, and Peninsular Florida where anomalies will be intense. In the Gulf Region, moderate surpluses are expected in southern Louisiana and Mississippi and moderate deficits in southeastern Alabama. Surpluses will linger in central Tennessee and Corpus Christi. Other areas of surplus include pockets of the Southwest and the upper South Fork Republican River in Colorado.

From January through March 2022 deficits are expected in central Idaho and pockets in the Rockies. Moderate surpluses are forecast in the Northwest, south-central Wyoming, and the North Platte and South Fork Republican Rivers. Deficits are also expected in northern Minnesota, the Carolinas, and southern Florida. Anomalies will be intense in the Salmon River Mountains, the Green River Watershed in Wyoming, the middle Cape Fear River region in North Carolina, and around Lake Okeechobee in Florida. Surpluses will be widespread in Michigan’s Lower Peninsula, reaching across its southern border; will emerge in pockets of southern Minnesota and central Wisconsin; and will linger in New York. Deficits will persist around Lake Champlain.

The forecast for the final months – April through June 2022 – indicates deficits, moderate overall, in Southern California, the Southwest, northeastern Minnesota, the Carolinas, and southern Florida. Moderate surpluses are forecast in northeastern South Dakota and scattered, small pockets in the Rockies. Please note that WSIM forecast skill declines with longer lead times.

IMPACTS
The official declaration of drought emergency now extends throughout California as of 20 October, accompanied by a ban on some types of wasteful water practices and a request for voluntary reductions in water use.

At the end of September, 11 major wildfires were still burning in California. The Dixie Fire, the second largest in state history, swept through nearly a million acres, lasted three months, and racked up the highest suppression cost - $610 million - ever spent by the state. The sheer scale of the battle was mind-boggling: over 6,500 people were engaged in the fight; over 1,000 miles of hose; nearly 200 bulldozers; and enough fire retardant to fill 31 Olympic-size swimming pools.

Elsewhere in the West, water levels at the nation’s two largest reservoirs, Lake Powell and Lake Mead on the Colorado River, reached their lowest levels since being filled. To avoid damage to Lake Powell’s hydropower equipment, water authorities ordered releases from upstream reservoirs.

Cattle ranchers in North Dakota are facing Dust Bowl conditions as drought turns grazing areas to stubble. Farmers are forced to choose between culling stock and paying up to five times as much for hay to keep herds fed.

NOTE ON ADMINISTRATIVE BOUNDARIES
There are numerous regions around the world where country borders are contested. ISciences depicts country boundaries on these maps solely to provide some geographic context. The boundaries are nominal, not legal, descriptions of each entity. The use of these boundaries does not imply any judgement on the legal status of any territory, or any endorsement or acceptance of disputed boundaries on the part of ISciences or our data providers.

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