25 states face ‘po­ten­tially un­prece­dented’ risk of se­ri­ous spring f lood­ing, sci­en­tists say

The Buffalo News - - FRONT PAGE - By John Schwartz NEW YORK TIMES

Vast ar­eas of the United States are at risk of flood­ing this spring, even as Ne­braska and other Mid­west­ern states are al­ready reel­ing from record-break­ing late-win­ter floods, fed­eral sci­en­tists said Thurs­day.

Nearly two-thirds of the Lower 48 states will have an el­e­vated risk of some flood­ing from now un­til May, and 25 states could ex­pe­ri­ence “ma­jor or mod­er­ate flood­ing,” ac­cord­ing to the Na­tional Oceanic and At­mo­spheric Ad­min­is­tra­tion.

“The flood­ing this year could be worse than any­thing we’ve seen in re­cent years, even worse than the his­toric floods of 1993 and 2011,” said Mary C. Erick­son, deputy di­rec­tor of the Na­tional Weather Ser­vice, in a con­fer­ence call with re­porters. The ma­jor flood­ing this month in Ne­braska, Min­nesota, Iowa and else­where is “a pre­view of what we ex­pect through­out the rest of the spring,” she said.

Some 13 mil­lion peo­ple could be ex­posed to ma­jor flood­ing, mak­ing this a “po­ten­tially un­prece­dented” flood sea­son, said Ed­ward Clark, di­rec­tor of NOAA’s Na­tional Water Cen­ter.

And much of the United States east of the Mis­sis­sippi River, as well as parts of Cal­i­for­nia and Ne­vada – in to­tal, ar­eas home to more than 200 mil­lion peo­ple – could see at least some flood­ing in the spring, the sci­en­tists said.

The pro­jec­tions were part of NOAA’s an­nual “Spring Out­look,” though the lan­guage of the 2019 re­port car­ried greater ur­gency than usual. That is not sur­pris­ing, since the basins of the Up­per Mis­sis­sippi and the Red River of the North have al­ready been hit with rain and snow this spring of up to twice nor­mal lev­els.

“We’ve set over 30 records in Ne­braska, Iowa and South Dakota” in the last week alone, said Kevin Low, a sci­en­tist with the Na­tional Weather Ser­vice’s Mis­souri River Basin Fore­cast Cen­ter. That flood­ing has dev­as­tated farm­ers and ranch­ers across the re­gion, put com­mu­ni­ties like Ham­burg, Iowa, un­der­wa­ter, and wiped out roads and bridges in oth­ers.

Gov. Pete Rick­etts of Ne­braska put a pre­lim­i­nary es­ti­mate of $1.4 bil­lion in dam­ages in his re­quest for a fed­eral dis­as­ter dec­la­ra­tion, in­clud­ing $439 mil­lion in dam­ages to pub­lic in­fra­struc­ture and $85 mil­lion to homes and busi­nesses.

Above-av­er­age rain­fall that sci­en­tists ex­pect for the spring, along with melt­ing snow, should add to the flood­ing and ex­tend it through the cen­tral and south­ern United States. NOAA iden­ti­fied the great­est risks for mod­er­ate to ma­jor flood­ing in the up­per, mid­dle and lower Mis­sis­sippi River basins, the Red River of the North, the Great Lakes, and the eastern Mis­souri River, lower Ohio River, lower Cum­ber­land River and Ten­nessee River basins.

The agency’s sci­en­tists also pre­dicted that the chem­i­cal runoff from the rains would cause above-av­er­age hy­poxia con­di­tions in the Gulf of Mex­ico and Ch­e­sa­peake Bay. That would cre­ate “dead zones,” ar­eas of water with low oxy­gen caused by nu­tri­ent pol­lu­tion that can kill fish and other ma­rine life.

More rain­fall in the Midwest is a pre­dictable con­se­quence of cli­mate change, ac­cord­ing to the most re­cent Na­tional Cli­mate As­sess­ment, which was pro­duced last year by 13 fed­eral agen­cies. A warmer at­mos­phere can hold more mois­ture, which comes down as pre­cip­i­ta­tion.

The cur­rent flood­ing in the Mis­souri River basin and be­yond has been caused in part by heavy rains, but has been fur­ther com­pli­cated by other fac­tors, like frozen ground that kept water from be­ing ab­sorbed.

An­drew Dessler, a pro­fes­sor of at­mo­spheric sci­ences at Texas A&M Univer­sity, said that un­der­stand­ing the role of cli­mate change in weather events like the Ne­braska floods re­quired ap­ply­ing the tools of a grow­ing field known as at­tri­bu­tion science. “With­out do­ing the anal­y­sis, you don’t know what role cli­mate change played,” he said. “Cer­tainly, floods hap­pened be­fore cli­mate change.”

How­ever, he added, heav­ier rain­fall events are among the most com­mon con­di­tions as­so­ci­ated with cli­mate change. Hu­mans have loaded so much planet-warm­ing car­bon diox­ide into the at­mos­phere that “the start­ing as­sump­tion has to be that cli­mate change is af­fect­ing ev­ery­thing” to some ex­tent, he said.

The Na­tional Weather Ser­vice de­scribes mod­er­ate flood­ing as in­volv­ing some in­un­da­tion of struc­tures and roads near streams, with some evac­u­a­tions; ma­jor flood­ing in­volves ex­ten­sive in­un­da­tion of struc­tures and roads and sig­nif­i­cant evac­u­a­tions.

By com­par­ing this year’s po­ten­tial flood­ing to the sea­sons of 1993 and 2011, Erick­son was cit­ing some of the worst weather dis­as­ters the United States has faced since the Great Mis­sis­sippi Flood of 1927.

The 1993 flood in the Midwest killed 50 peo­ple and caused $15 bil­lion in dam­age; a re­porter for The New York Times called it “a wa­tery ram­page by na­ture like no other.”

In the 2011 floods, the Army Corps of En­gi­neers took the ex­tra­or­di­nary mea­sure of blow­ing up 11,000 feet of Mis­sis­sippi River levee to let water flow into the Birds Point flood­way in Mis­souri, sav­ing the lit­tle Illi­nois town of Cairo but in­un­dat­ing more than 100,000 acres of farm­land and homes.

New York Times

A man nav­i­gates the flood wa­ters in Ham­burg, Iowa, on Mon­day. With flood­ing al­ready reach­ing his­toric lev­els in parts of the United States, fed­eral sci­en­tists warn to ex­pect more through­out the spring – es­pe­cially bad news for farm­ers and ranch­ers.

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