Shocking Update on a Dry Mississippi

October 26, 2022

This is getting bad.
Perspective from Jeff Masters and Bob Henson, my colleagues at Yale Climate Connections:

The shrunken Mississippi River, flowing at its lowest rate on record along much of a 270-mile stretch, will receive a minor short-term bump in water levels this week from Hurricane Roslyn’s rains. However, with another La Niña winter in the cards, the long-term outlook for the river is unfortunately very dry.

Intense, widespread drought conditions across much of the U.S. this year have cost more than $9 billion and are causing havoc to shipping on the mighty Mississippi River, which in three states has hit its lowest levels on record. The low water levels come at an extremely inopportune time – during the peak of the U.S. harvest season, when barges carrying grain provide the predominant transportation method to carry America’s bounty. Barges going downriver carry about 60% of U.S. grain exports to the world. Going upriver, Mississippi River barges transport petrochemicals, fertilizers, and raw materials essential for the functioning of U.S. industry and agriculture, making the Mississippi River the lifeblood of the American economy. If barge traffic on the Mississippi River is slowed for an extended period of time, the entire U.S. economy suffers, with impacts to the global economy and world food supplies.

As reported by Bloomberg on October 21, barge shipments of corn during the first week of October were down 50% from the same time in 2021, and more than 2,000 barges were backed up. The low water levels have also allowed salt water to move upriver to threaten drinking water supplies in New Orleans, forcing the Army Corps to build an underwater dam to stop the upstream advance of the ocean water.

The ongoing U.S. dryness is even more impressive in its breadth than in its intensity. In the weekly U.S. Drought Monitor assessment released on October 13, a total of 81.8% of the contiguous United States was either abnormally dry (D0) or in some stage of drought (D1-D4). This was the largest weekly percentage tallied in the 1,100-plus weeks that have elapsed since the Drought Monitor began in January 2000.

The record was again broken just a week later, on October 20, when the fraction of the contiguous U.S. at D0-to-D4 levels climbed to 82.2%. At some point in 2022, all 50 states have experienced drought, and only three states – Alaska, West Virginia, and Delaware – were not experiencing at least D0 levels of dryness during the past week.

None of the specific drought categories (D1, D2, D3, or D4) are at record-high coverage levels right now, so it’s the sheer geographic spread of dry conditions that’s most noteworthy about the current 2022 drought. But the intensity is rising fast. The Drought Severity and Coverage Index, which incorporates both drought strength and drought scope, jumped from 150 in early January to 194 by late October. The highest value on record is 215, recorded on Aug. 14, 2012.

The longer-term outlook remains worrisome for U.S. drought into the winter of 2022-2023, as an unusual third-year La Niña event (the first such sequence since 1998-2001) is now in place and expected to continue for at least the next several months. NOAA’s latest Seasonal Drought Outlook, issued on October 20, calls for drought conditions to either persist or expand across most of the western and southern three-quarters of the contiguous U.S. from now through January.

Below, current soil moisture and outlook.

More details at the Yale Climate Connections link.


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