Texas residents are now cleaning up after twisters in the state killed at least 11 people and injured dozens on Saturday (local time).
Meanwhile, snow and ice are pelting the American Midwest, and flooding continues in Arkansas, Missouri and Illinois.
The severe weather events in the US in the past week have caused around four dozen deaths.
Heavy snow, ice and blustery winds are pounding the country's midsection, and heavy rain has hit already-waterlogged areas.
More than 2100 flights were cancelled nationwide on Monday, most of them in Chicago. Around 3700 more flights were delayed, according to flight-tracking service FlightAware.
A state of emergency has been declared in Oklahoma, where blizzard conditions and heavy rains made driving treacherous.
The body of a 22-year-old man was found in northern Oklahoma, while a second man is still missing after the two went duck hunting together and their boat capsized. The body of a 36-year-old man who tried to cross a creek in his ute near the town of Arpelar was also recovered by the Oklahoma Highway Patrol.
In Arkansas, a 31-year-old man died in a storm-related drowning.
A state of emergency has also been declared in Missouri, where heavy rains have caused major flooding. Ten people have died in that state from the storms, with the death toll expected to rise.
The Mississippi River is at potentially record levels, and Mississippi state is seeking a federal disaster declaration after tornadoes hit there last week.
In Georgia, the body of a man whose car was swept away in floodwaters was recovered.
In Texas, as many as 1450 homes were damaged or destroyed by at least nine tornadoes, which hit the northern part of the state on Sunday. The second-most powerful class of tornado, an EF-4, with winds of more than 320km/h, hit Texas' Garland region, killing eight people, injuring 15 and damaging more than 600 structures.
"I've never seen anything like this, with this scale of destruction," Police Chief Mitch Bates told media.
He says the tornado victims included a one-year-old in a car thrown from an overpass on Interstate 30. An infant in Collin County, north of Dallas, also died after CPR on the newborn girl was unsuccessful.