SAN MARCOS, Texas — A tornado raged through a Mexico border city shortly after daybreak Monday, destroying homes, upending cars and killing at least 10 people.
In Texas, crews searched for people believed to be missing after a vacation home was swept away by a river that had become swollen from a line of storms that stretched from the Gulf of Mexico to the Great Lakes.
The system dumped record rainfall on parts of the Plains and Midwest, spawning tornadoes and causing major flooding that forced at least 2,000 Texans from their homes.
Authorities in Mexico said 10 people had been confirmed killed so far in the twister, which struck Ciudad Acuna around 6:40 a.m.
Photos from the scene showed cars with their hoods ripped off, resting upended against single-story houses. One car's frame was bent around the gate of a house. A bus was flipped and crumpled on a roadway.
Ciudad Acuna is a city of about 100,000 across the border from Del Rio, Texas.
Top state officials set out to review the damage and coordinate the response, said Rosario Cano, spokeswoman for the interior department of the northern state of Coahuila.
In the U.S., three deaths were blamed on the storms Saturday and Sunday, including two in Oklahoma and one in Texas, where a man's body was recovered from a flooded area along the Blanco River, which rose 26 feet in an hour and created huge piles of debris.
The line of storms was expected to linger over a large swath of the region Monday.
Among the worst-affected communities were Wimberley and San Marcos, which are in Central Texas along the Blanco River in the increasingly popular corridor between Austin and San Antonio.
"It looks pretty bad out there," Hays County emergency management coordinator Kharley Smith said of Wimberley, where an estimated 350 to 400 homes were destroyed and where three people remained missing late Sunday. "We do have whole streets with maybe one or two houses left on them and the rest are just slabs."
Kristi Wyatt, a spokeswoman for San Marcos, said about 1,000 homes were damaged throughout Hays County, which includes Wimberley and which will be toured Monday by Gov. Greg Abbott. Five San Marcos police cars were washed away and the fire house was flooded.
Rivers swelled so quickly that whole communities awoke Sunday surrounded by water. The Blanco crested above 40 feet — more than triple its flood stage of 13 feet — swamping Interstate 35 and forcing parts of the busy north-south highway to close. Rescuers used pontoon boats and a helicopter to pull people out.
After a surge of mud and water flooded their cottage in Wimberley, John and Valerie Nelson fled through waist-deep waters in darkness early Sunday with transformers sparking and trees crashing around them. The single-story house, which had been Valerie Nelson's grandmother's, had been carefully rebuilt on stilts so that it would be able to withstand even the worst flooding.
"I'm absolutely dumbfounded," said Valerie Nelson, who has owned the property for about 50 years. "I didn't think the water would ever get that high."
Hundreds of trees along the Blanco were uprooted or snapped, and they collected in piles of debris that soared 20 feet high.
"We've got trees in the rafters," said Cherri Maley, the property manager of a house whose entire rear portion had collapsed with the flooding, carrying away furniture.
"We had the refrigerator in a tree," she said. "I think it's a total loss."
About 1,000 residents were evacuated from roughly 400 homes near an earthen dam at Lake Lewis, about 50 miles north of Houston. Montgomery County emergency management officials fear the dam could fail due to the flooding. Agency spokeswoman Miranda Hahs said it was not clear when residents would be allowed to return home.
A tornado briefly touched down Sunday in Houston, damaging rooftops, toppling trees, blowing out windows and sending at least two people to a hospital. Fire officials said 10 apartments were heavily damaged and 40 others sustained lesser damage.
Dallas faced severe flooding from the Trinity River, which was expected to crest near 40 feet Monday and lap at the foundations of an industrial park. The Red and Wichita rivers also rose far above flood stage.
In Colorado, a mandatory evacuation notice was issued Sunday for residents in the northeastern city of Sterling, and several counties planned to ask the governor for a disaster declaration.
This May is already the wettest on record for several Plains cities, with days still to go and more rain on the way. Oklahoma City set a new monthly rainfall total this weekend — 18.2 inches through Saturday, surpassing the previous record of 14.5 in 2013. So far this year, Oklahoma City has gotten 27.37 inches of rain. It got only 4.29 inches all of last year.
The recent rainfall may officially end the drought that has gripped the region for years, according to Forrest Mitchell, a meteorologist at the weather service's office in Norman, Oklahoma. He said many lakes and reservoirs are full.
Stevenson reported from Mexico City.
Associated Press writers David Warren in Dallas and Tim Talley in Oklahoma City contributed to this report.