A 6-year-old boy was killed in Oklahoma on Thursday after the car he was riding in skidded in the heavy rain.
In southeastern Texas, residents were plucked from treetops, homes and cars in more than 20 rescues. At least 10 people were hospitalized, and as many as 200 homes were damaged.
Half of Robertson County - 400 square miles - was under floodwater after 17 inches of rain fell in nine hours.
Elizabeth Keyes, 26, fled her trailer with her three young children once the water became knee-deep in Hearne, one of the worst-hit towns.
``I just grabbed diapers, bottles and left,'' she said. Returning later in the day, she found her home was leaning against a tree, surrounded by her floating belongings.
Red Cross and emergency workers were going door to door Friday to assess the damage. Some roads remained closed.
``We've been praying for rain, and we got some, but it was more at one time than we wanted,'' County Judge Fred Elliott said.
A twister struck Thursday in nearby Bryan.
Cathy Rios, 54, said all she could do is pray as her mobile home was tossed from side to side.
``I just kept screaming and screaming and screaming to God, `Help me,''' Rios said. ``It was just awful. I don't know how I got out alive. I was just waiting for a tree to fall on me or the wind to blow me away.''
The rains delayed and canceled some flights at Houston airports.
The area remained under flood watches and warnings Friday, as did parts of Louisiana and Mississippi, and more rain was expected.
In Sequoyah County, Okla., a car slid off Interstate 40 and into a tree, killing the 6-year-old from Maryland.
Winds of 60 mph ripped the roof off a barn near Bristow and overturned a travel trailer in nearby Tulsa County. The high winds also downed power lines, leaving 20,500 customers in the Tulsa area without power, officials said.
Parts of North Dakota, meanwhile, reported 8 inches of snow, giving some residents a chance to fire up their snowmobiles as workers repaired electrical lines.
``They were cruising up and down the ditches having a good old time,'' said Kerry Mikkelsen, line superintendent for the Cavalier Rural Electric Co-op in Langdon. ``Just so they can say they were snowmobiling in May.''
Langdon residents estimated they got about 7 inches of snow from the storm, which also brought strong winds and heavy ice to the region. Minot, Rolla and Crosby each reported around 8 inches of snow.
Bismarck tied a record low for the date on Thursday, at 27 degrees, the National Weather Service said, and Dickinson set a record low at 22 degrees.
The Milwaukee area's sewerage district dumped hundreds of thousands of gallons of rainwater and untreated sewage into the Milwaukee and Menomonee rivers after days of soaking rains.
``I can't stress how disappointed we are that this happened. Unfortunately, this was such an intense rain, there was no other option,'' spokesman Bill Graffin said.
In Minnesota, the Roseau River crested at 20.5 feet - 4.5 feet above flood level - but the town of Roseau stayed dry, thanks to sandbagging lessons learned in a flood two years earlier, when the river reached 23 feet and caused more than $120 million in damage.
``We're officially changing gears from a flood-fight mode to a monitoring mode,'' Mayor Jeff Pelowski said Friday.
