At least three people have died and hundreds of homes have been destroyed in flash flooding in the southern US.
Two people were killed in weather-related accidents in Oklahoma and a man lost his life in San Marcos, Texas.
Some areas saw up to 10 inches (25cm) of rain over a 24-hour period, with more predicted across the region.
Eight people, including two children, were reported missing along the Blanco river in Texas, local media report.
Jonathan McComb was staying at a house in Wimberley with his wife and their young son and daughter when they were swept away.
Mr McComb was taken to hospital with serious injuries, but his family has not yet been found. Five others were also reportedly dragged away by the floodwaters.
His father, former county commissioner Joe McComb told Kiii TV: “It is in the Lord’s hands… we’re praying for the best.”
‘Worst I’ve seen’
There were numerous other rescues on Sunday after banks burst, and hundreds of homes were destroyed across the region.
Warnings and alerts stretch from Colorado through to Arkansas, Louisiana, Missouri and eastern Kansas.
The Blanco is one of the worst hit rivers in Texas.
At one point it crested at 43ft (13m) – some 30ft above the designated flood stage and 7ft higher than the 1929 record.
A flash flood emergency – reserved for the most life-threatening situations – is in effect in the river basin area.
Some 1,000 people nearby were evacuated from their homes and parts of the Interstate 35 highway were flooded and closed.
Rudy Olivo, a resident of San Marcos, told Associated Press: “This is the worst I’ve seen it because the water rose so fast.”
San Marcos emergency management coordinator, Kenneth Bell, said the body of one man had been recovered but had no more details.
Kristi Wyatt, communications director for the town, said: “We have people on car tops and rooftops awaiting rescue. People in homes are going to higher levels.”
She said hundreds of people were now in evacuation centres and that floodwaters had washed away five police cars.
A tornado hit Houston briefly on Sunday, damaging buildings and injuring at least two people.
Warnings of more tornados have been issued for parts of Iowa, Kansas, Missouri and Illinois.
In parts of San Antonio water exploded from sewer covers.
A mandatory evacuation was ordered at Lake Lewis, 50 miles (80km) north of Houston, which itself saw high winds bringing down trees and blowing out windows.
Residents in Wichita Falls, also in Texas, were warned the Wichita river could burst its banks.
A fire-fighter died in Oklahoma when he was swept away while taking part in a rescue effort in the town of Claremore, in the north-east of the state. He was named as Capt Jason Farley.
A woman was also killed in a weather-related traffic accident in Tulsa.
Residents were rescued from roofs in the state’s Cleveland and Comanche counties.
The National Weather Service says Oklahoma City already has a new monthly rainfall record for May – at 18.19 inches.
In Colorado, El Paso and Pueblo counties and the city of Sterling were badly affected.