UPDATED throughout at 3:15 p.m.
A last wave of storms is expected to bring another 1/2 inch or more of rain to the metro area Monday evening, not enough for a repeat of the early morning's flash flooding.
Through Monday afternoon, Lambert-St. Louis International Airport recorded 2.4 inches Monday and nearly four inches since the storms arrived Friday night. But many areas, especially to the south, were pounded with downpours of as many as six inches just since Sunday.
In De Soto in Jefferson County, firefighters and police rescued about three dozen people before dawn Monday who live along Joachim Creek. The creek already was over its banks by 4 a.m. and quickly rose several more feet. The Joachim had returned to its banks by early afternoon.
One of their rescues was a woman who was nine months pregnant and began having labor pains. De Soto assistant fire chief James Maupin said paramedics transported her to a hospital.
Whether she delivered her baby by Monday afternoon could not be determined.
Other De Soto residents rescued by boats were taken to two churches to wait out the flooding. "The creek rose rather quickly this time and a lot of people were still home sleeping," Maupin said.
Power outages continued to plague parts of St. Louis County on Monday morning. In the predawn hours, Ameren reported about 15,000 customers without power. By 2:30 p.m. it was down about 1,600, mainly in the area between Park Hills and Farmington, Mo., about 60 miles south of St. Louis.
In Granite City, waist-high water covered several stretches of Maryville Road Monday morning, police said. Parts of downtown also were impassable to cars.
In State Park Place near the Cahokia Mounds historic site, residents packed sandbags Monday on low spots along Canteen Creek at Fairview Boulevard.
In Southeastern Missouri, St. Francois, Iron and Reynolds counties had five or six inches of rain Monday. Ameren Illinois had about 770 customers scattered throughout southern Illinois still without power.
In the metro area, power outages hit Ladue, Rock Hill and Fenton areas the hardest. Ameren said it lost its Rock Hill substation because of the storm.
Charley Kelly, a meteorologist with the National Weather Service office in Weldon Spring, said the metro area could get another half-inch to inch of rain when another band of showers moving up through southern Missouri arrives in the early evening.
"We are not going to have the flooding problem we had this morning," Kelly said Monday afternoon.
By Tuesday afternoon, the rain is expected to clear. No storms are back in the forecast until the weekend.
On Monday morning, one of the trouble spots for flooding in St. Louis County was around Rock Hill and Brentwood, where the notorious Deer Creek rose again from its banks.
The Weather Service issued a flash-flood warning at 4 a.m. Monday.
Bob Holthaus of Holthaus Technologies, 8410 Manchester Road, scrambled when he woke up at 4 a.m. to the sound of the Weather Service's alert. He went to his office to move televisions, stereos and automation equipment onto higher shelves.
"The garage has 24 inches of water in it," he said by telephone at about 8 a.m., noting that the water was just starting to recede quickly.
The creek, which runs behind his business, backed up and flooded his and neighboring businesses -- just as it did just after Christmas, when nearly nine inches of rain fell for three days beginning Dec. 26.
"To have it happen twice in one year is unheard of," Holthaus said. "You can't beat mother nature."
Some stores at Brentwood Center, 8500 block of Manchester Road, were sweeping water out Monday morning.
"They have a new saying: It is what it is," said Paul Johnson, owner of Kings and Queens Barber and Beauty. "It could have been a lot worse. Other than a little elbow grease, I'll be okay."
Last December, firefighters took him out of the same store by boat. He said the road often floods. He'd like to move but business is good.
Nearby, Brentwood Boulevard near Marshall Road was closed because of water on the road. Some Metro bus lines are using different routes because of the road closures.
Tommy Bahn, 61, owner of Cousin Hugo's in Maplewood, said water rose within one inch of the last step inside the restaurant early Monday.
"I am always on pins and needles when it rains like that," said Bahn, who doesn't have flood insurance for his business, which abuts Deer Creek Park.
The Weather Service said more than six inches of rain fell in Mapaville, between Hillsboro and Herculaneum in Jefferson County from 2 p.m. Sunday and 6 a.m. Monday. Other rain totals include nearly 4 inches of rain in the last 24 hours in Eureka, about 5 inches in Jennings since midnight Sunday, 4 inches in Edwardsville, 3 inches in Freeburg and 4½ inches in Pontoon Beach.
The morning commute in the St. Louis metro area was slow-going, and a handful of vehicle crashes were blamed on standing water and vehicles hydroplaning. Highway 141 beneath Interstate 44 was flooded and shut down. St. Louis fire officials said they rescued a motorist trapped in high water in the 8000 block of Hall Street.
The Weather Service issued a flood warning along Dardenne Creek in St. Charles County. It rose six feet in three hours early Monday but began falling after staying below flood stage.
The area rivers are rising but aren't expected to repeat anything close to last December. The Meramec River at Valley Park was expected to crest Wednesday one foot over flood stage after a 17-foot rise. But flood stage is of little consequence Valley Park's levee was completed.
The Meramec was expected to stay below flood stages at Pacific, Eureka and Arnold. The Big River at Byrnesville was expected to crest at 21.8 feet Wednesday, or nearly six feet over flood stage, after a 19-foot rise. The Big flows into the Meramec near Eureka.
The Metropolitan St. Louis Sewer District reported that the storm Monday morning overwhelmed the final treatment process at its Fenton plant. The first two primary cleaning processes continued to function, but the district warned people not to go into the Meramec from Fenton to the Mississippi River -- or wash thoroughly with soap if they do.
The December flood knocked out that plant for three months.
MSD also reported about 200 scattered residential sewer backups on Monday.
The precipitation is connected to the same storm system that pounded Louisiana with record amounts of rainfall, causing devastating flooding. Kelly says the low-pressure, tropical storm system extending north from the Gulf of Mexico is merging with a separate front south of the St. Louis area. But without the ocean to supply moisture and other factors, inland rainfall will not be nearly as severe.
“People out there really want to pay attention, especially with the flash flood potential of this event,” said Kelly. “If you live near rivers and streams, be very vigilant, especially as we get into the evening.”
Jesse Bogan, David Carson, Kim Bell, Bryce Gray, Leah Thorsen and Tim O'Neil of the Post-Dispatch contributed to this report.