United States: Widespread water deficits will persist in the west

22 July 2021

THE BIG PICTURE
The 12-month forecast ending March 2022 indicates widespread water deficits of varying intensity in the U.S. West, Pacific Northwest, Rocky Mountains, Northern Plains, and Northeast. Deficits will be exceptional in many areas including California, Oregon, and North Dakota. Deficits on the Colorado River will be severe surrounding Lake Mead and moderate in the river’s upper basin.

Anomalies will be less intense - moderate to severe overall - in South Dakota, Minnesota, Iowa, pockets of Wisconsin, and northern Michigan.

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In the U.S. Northeast, deficits ranging from moderate to exceptional are expected in Maine, New Hampshire, Vermont, and near the St. Lawrence River in Upstate New York. Deficits are also forecast in smaller pockets of western Pennsylvania, Virginia, and the eastern region of the Carolinas. Peninsular Florida will experience moderate deficits between Jacksonville and Orlando and more intense deficits south of Lake Okeechobee.

Surpluses are forecast in the Mississippi River region from Illinois to the Gulf Coast. Pockets will be moderate and sparse in Illinois, Missouri, and Tennessee, but more widespread approaching the Gulf, through Arkansas, Louisiana, and Mississippi and into Texas and Alabama. Anomalies will be exceptional near New Orleans and into coastal Mississippi. Moderate surpluses will follow a stretch of coast in Texas near Corpus Christi.

Elsewhere in the nation, surpluses are forecast along Nebraska’s southern border into Colorado along the Republican River and in a pocket of north-central Kansas. Surpluses are also expected in a pocket of south-central Colorado leading to the Upper Canadian River region in New Mexico.

Outside the contiguous U.S., Alaska can expect deficits in the northeast, in a large block east of Norton Sound, and near Anchorage and Valdez. Surpluses are forecast west of Bethel, near Iliamna Lake, in the eastern Alaska Range, and near Juneau. In Hawaii, surpluses are expected in Oahu, Molokai, and Lanai, and deficits in Maui. Moderate to severe deficits are forecast for Puerto Rico.

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

The forecast through September indicates widespread deficits in the West, Pacific Northwest, Northern Plains, Great Lakes, and Northeast. Deficits will shrink in Nevada, Utah, Arizona, and New Mexico. Exceptional deficits will increase in Northern California and the Pacific Northwest. Anomalies in the Northern Plains will downgrade to severe, and moderate deficits will increase in Wisconsin. Deficits will retreat from the southern half of Michigan’s Lower Peninsula but persist elsewhere. Intense deficits will persist in the Northeast. Deficits will shrink in New York, downgrade in the eastern Ohio River Basin, and shrink in the Mid-Atlantic States and in Florida, persisting south of Lake Okeechobee. Widespread surpluses will persist in Gulf Coast States from eastern Texas through Alabama with extreme anomalies in Mississippi. Surpluses will reach into Oklahoma, Arkansas, and Tennessee. Surpluses elsewhere include Missouri, the Republican River through Nebraska into Colorado, northeastern New Mexico into Colorado, the Canadian River through the Texas Panhandle, and a pocket in central Texas.

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From October through December, anomalies will shrink considerably. Deficits will remain intense in Idaho’s Salmon River region and from the Great Salt Lake in northern Utah into Idaho and Wyoming. Deficits will be severe on the Missouri River through Montana. Pockets of deficit are forecast for western Montana, central Oregon, and western Colorado. Elsewhere, deficits are forecast in northern Minnesota and pockets of Iowa, Wisconsin, Michigan, and southern Florida. Surpluses will persist in aforementioned areas of Nebraska, Colorado, Kansas, New Mexico, and the Texas Panhandle.

The forecast for the final months – January through March 2022 – indicates surpluses, particularly on rivers, in Nebraska, Wyoming, Colorado, northeastern New Mexico, and the Texas Panhandle. Intense deficits will persist in southwestern Wyoming and central Idaho. Surpluses are also forecast for Idaho and pockets of the Northwest. Deficits will persist in northern Minnesota and southern Florida. Pockets of moderate surplus will emerge in the Great Lakes and Northeast.

Please note that WSIM forecast skill declines with longer lead times.

IMPACTS
No immediate relief is in sight from drought in the U.S. West. As of 20 July, the U.S. Drought Monitor reported drought in 99 percent of the region. Similarly, many other parts of the country are suffering dry conditions as well with drought affecting 100 percent of Oregon, Idaho, Utah, and North Dakota; 93 percent of New Mexico; and 75 percent of Maine.

Already facing drought, record-breaking heat hit the Pacific Northwest claiming 116 lives in Oregon at least 112 in Washington State, making it the most deadly weather-related event in Washington history.

The combination of drought and heat has created dangerous fire conditions. The Bootleg Fire in southern Oregon has destroyed nearly 400,000 acres and created fire clouds that produced lightening and a fire tornado. The fire has destroyed 70 homes and 100 outbuildings. Another 2,000 homes have been ordered to evacuate. Smoke from the Bootleg and other western fires has travelled 3,000 miles east reaching New York and Philadelphia and creating hazardous health conditions as particular matter sits on major metropolitan areas.

As drought in the Northern Plains leaves pastured desiccated, farmers in North Dakota are culling herds. In South Dakota, a gubernatorial executive order will temporarily allow haying and grazing on state acreage designated for conservation.

In Michigan, while much of the state has been in mild to severe drought, torrential rainfall in Detroit at the end of June and again in mid-July left major highways flooded stranding vehicles and motorists.

Tropical Storm Elsa raced up the Northeast Coast in early July downing power lines, flooding streets, and pouring into New York’s subway system.

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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