Nature
PUBLISHED
A stalled atmospheric river is likely to result in multiple rounds of extreme rainfall being dumped on parts of the central US over the coming days, with forecasters warning of unprecedented flash floods. The greatest danger is expected over an area stretching from Arkansas to Kentucky, though deluges are likely all the way up to Ohio.
The rest of this article is behind a paywall. Please sign in or subscribe to access the full content.“A multi-day, potentially historic heavy rainfall event may produce catastrophic and life-threatening flooding through Saturday from the Ozarks into the Ohio River Valley,” warned the National Weather Service (NWS) in its daily update on Thursday, April 3. “A High Risk of Excessive Rainfall (level 4/4) is in effect Thursday from southwestern Kentucky into western Tennessee and northeastern Arkansas where the greatest threat for numerous instances of life-threatening flash flooding exists following heavy rainfall over the same areas Wednesday."
According to Accuweather, four months' worth of rainfall could fall in just five days across a 1,600-kilometer (1,000-mile) swathe of the country, resulting in numerous rivers and other watercourses bursting their banks. "Should the amount of rain occur that we anticipate over the middle of the nation, it would exceed the 500 to 1,000-year average,” said AccuWeather Senior Storm Warning Meteorologist William Clark in a statement.
These unique conditions are the work of an atmospheric river, which is a long, narrow column of water vapor flowing through the atmosphere. Originating in the tropics, the ribbon of humidity over this part of the US usually flows from west to east, yet has now become blocked by a region of high pressure off the southeastern US coast.
As a consequence, the atmospheric river has ground to a halt over the central part of the country, where it is likely to offload multiple bouts of colossal rainfall throughout the rest of this week. The NWS says that the stalled system will “fuel continued rounds of intense downpour-producing thunderstorms throughout the region, but with a particular focus centered on the Lower Ohio Valley into the Mid-South.”
According to Accuweather, more than a foot of precipitation is expected in certain areas, representing more than twice the amount of rain that triggered deadly floods in Kentucky in February of this year. Overall, it says that more than 46 million people will be affected by the torrential rainfall, with 13 million of these residing in areas with a high-to-extreme risk of flooding.
“Communities in the region should prepare for possible long duration and severe disruptions to daily life,” says the NWS. In particular, those traveling along roads near rivers and streams are urged to be vigilant for rising water levels, and everyone living within the affected region is advised to prepare to move to higher ground if necessary.
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