A new round of powerful storms is causing more flooding in multiple states, with parts of the Deep South likely on the receiving end of some of the most severe weather through the end of the week that will impact about 40 million Americans.
The National Weather Service cautioned residents of southeastern Texas, Louisiana and Mississippi to brace for a multiday barrage of dangerous heavy rain and flash flooding.
The agency issued a flash flood watch for large portions of southeast Texas and Louisiana on Thursday, to remain in effect through Saturday evening. Anywhere from 4 to 8 inches of rainfall are expected in the area, the NWS said.
On Tuesday, surprise rainstorms "submerged streets and swamped homes" in parts of Houston, the Houston Chronicle reported. The unexpected torrential rains also inundated schools and businesses, and stranded motorists and school children for hours.
In all, 10 inches of rain fell in certain areas, leading to several high-water rescues by emergency responders. The Red Cross set up a shelter at a church northeast of Houston's downtown.
While dry weather on Wednesday provided a reprieve in some areas, the soil is still saturated. A large new storm system will cause the rainfall to run off quickly and lead to more flooding.
The NWS said the moving storm may also bring with it damaging winds, large hail and brief tornadoes.
Houston Public Media reports that could lead to "potential cresting on several regional rivers such as the Brazos, San Jacinto, San Bernard and Trinity. The bayous will also have to be monitored."
A deluge in Austin on Wednesday led to at least one fatality after a man believed to be in his 50s was swept away in the current of raging floodwaters, the Austin-American Statesman reported.
An NWS team is examining damage from a powerful storm that ripped through Arkansas on Wednesday night, KUAR reporter Michael Hibblen told NPR.
"Police in Pine Bluff say four people were injured — one seriously — after a violent storm ripped the roof off an apartment building," Hibblen said, adding that about 150 people have been displaced.
Following four violent windstorms across the region on Wednesday, Accuweather reported the risk of tornadoes was lower as of Thursday. However, "there will still be a risk of a few isolated tornadoes over land each day, as well as the potential for a couple of waterspouts near the Gulf Coast."
Along the Mississippi River Valley, which has already endured more than a month at dangerous levels, more than 30 river gauges are reporting major flooding, Paula Cognitore, a service coordination hydrologist for the National Water Center, told NPR.
"The rainfall that soaked Missouri and Kansas earlier this week will work its way into the Missouri River, which connects to the main stem of the Mississippi just north of St. Louis," which will prolong major flooding, Cognitore said.
In addition to Missouri, Kansas and Texas, Cognitore said, South Dakota, Iowa, Illinois, Oklahoma, Louisiana and Mississippi have been experiencing major flooding since March when snow melt began entering waterways.
She said the added runoff has slowed the river from receding.
"The good news is this part of the country — the Great Plains and upper Mississippi — should be getting a break from heavy precipitation over the next week or two," Cognitore added.
Flooding, driven by climate change, is getting more frequent and severe across the country, NPR's Rebecca Hersher reported.
"In some parts of the Midwest and East Coast, extreme rain has already increased more than 50% since the early 1900s," Hersher said.
She explained warmer ocean water is part of the problem, and record-high temperatures in the Gulf of Mexico act like an engine to make hurricanes larger and wetter. The resulting rainfall flows into rivers that were not engineered to withstand current weather conditions.
"In all, tens of billions of dollars' worth of river trade and farmland are in danger. And more than $100 billion in real estate is threatened by rising seas," Hersher noted.
Blasts of widespread thunderstorms are anticipated across the Great Lakes region, Ohio and Tennessee Valleys and into the Lower Mississippi Valley and Southern Plains, NWS warned.
Meanwhile, a full-fledged snowstorm is expected in the northeastern stretches of Minnesota and neighboring northwest Wisconsin.