Flood watches and warnings remained in effect Tuesday for portions of the south-central USA after a day of torrential rain that left houses and streets flooded and cars stranded.
The National Weather Service said more than 30 million people are threatened by flooding this week across parts of Texas, Louisiana, Oklahoma and Arkansas, an event Accuweather called “historic.” 
“Rounds of rain and thunderstorms have inundated much of the south-central U.S. since Monday, especially for many in Texas and Louisiana, and relief is not expected until late this week,” AccuWeather meteorologist Adam Sadvary said.
Louisiana was hit especially hard Monday: The weather service said in a Facebook post that south Lake Charles in western Louisiana saw 12 to 15 inches of rain in a 12-hour period. 
Louisiana Gov. John Bel Edwards said at a news conference Tuesday that there were two weather-related deaths. The body of 33-year-old Justin Blaine Thompson was found in a vehicle submerged in water under a Baton Rouge, Louisiana, overpass, the coroner’s office said. 40-year-old Alvarado Morentes Hermelindo died and another person was missing after their car crashed into a canal Monday evening, Louisiana State Police said.
“Unfortunately, more rain is on the way,” Edwards said and pointed out that the ground is already saturated. “While we hope that the worst of this rainfall is behind us, we can’t be sure of that.”
A flash flood emergency was issued overnight Monday by the weather service for the southeast Baton Rouge area, where up to a foot of rainfall was estimated to have fallen, according to Weather.com. The Baton Rouge Fire Department responded to more than 300 calls overnight of people trapped in cars or homes starting to flood.
Lake Charles Mayor Nic Hunter said the city didn’t have an exact number of flooded homes but it would probably be in the hundreds. Hunter was mayor last fall when the city was slammed by Hurricane Laura on Aug. 27, then six weeks later by Hurricane Delta.
Rainfall totals will probably meet the threshold for a 100-year event, Hunter said Monday.
“We are a very resilient people. We are a very strong population. But, you know, eventually you do kind of get to a point where you ask Mother Nature: What more can you do to us?” Hunter said Tuesday.
By Tuesday the waters had largely receded, but more rain is expected across the region this week.
“It is mind-boggling,” said Lake Charles resident Patrick King. He was at a car rental office Tuesday after his truck was flooded Monday. He still hadn’t moved back into his house after it flooded during October’s Hurricane Delta but had recently had new furniture delivered to the home. Then it flooded again.
King spent Tuesday morning mopping the house and preparing for further rains.
“I picked up everything I could get off the floor and got it elevated,” he said.
This is the third-wettest May in history for Lake Charles, AccuWeather said. 
Louisiana flooding:‘Dangerous and potentially life-threatening’ flash floods, thunderstorms hammer Louisiana and Gulf Coast
Rain was expected to continue to drench the region through at least Thursday, producing numerous areas of flash flooding. “Additionally, the heavy rain may cause many streams and possibly larger rivers to flood,” the weather service said.  
Severe thunderstorms capable of producing damaging wind gusts, large hail and isolated tornadoes were expected through Tuesday night in central Texas and southern Oklahoma, AccuWeather said. 
Cities that may be hit by severe weather later Tuesday include Dallas, San Antonio and Abilene, Texas.
In the northwestern USA, winter refuses to relinquish its grip on the region: Rain and snow will develop over parts of the Pacific Northwest into parts of the northern Rockies over the next couple of days, the weather service said. A winter storm watch was in effect in western Montana.
Contributing: Elinor Aspegren, USA TODAY; The Associated Press