Heavy rains fueled by the meeting of two strong storm systems, one the remnants of Hurricane Patricia, pounded southeastern Texas triggering flash floods and derailing a freight train as the heavy weather descended upon Houston early on Sunday.
The National Weather Service predicted 6 to 12 inches (15 to 30 cm) of rain for coastal areas including southwest Louisiana by Monday morning, exacerbated by tides up to 5 feet (1.5 meter) and wind gusts up to 35 mph.
The rain systems were intensified by Patricia, downgraded to a tropical depression after crashing into Mexico's west coast as a powerful hurricane.
As the storms moved eastward early on Sunday, cities in the state's flood-prone Gulf of Mexico region including Houston, the state's second-most populous metropolitan area with 6.1 million people, braced for potential floods.
Texas has experienced widespread flooding in the aftermath of Hurricane Patricia. (Getty) Source: AAP
Mayor Annise Parker warned residents to stay away from wet roads after dark and be aware that flooding is likely. A flash flood warning was issued late Saturday into early Sunday. The National Weather Service said the area could be swamped with more than a foot of additional rain. Officials urged vigilance, reminding residents of deadly past flooding.
"Some people lost their lives in high-water incidents," said Harris County Judge Ed Emmett, whose county includes Houston.
"We're going to get a lot of rain tonight and it's going to result in some high water situations so for heaven's sake be careful," Emmett warned.
A series of storms in May triggered floods and led to 21 deaths. In the Galveston area, authorities urged a voluntary evacuation of the elderly and residents with medical issues on the Bolivar Peninsula near Galveston Bay.
The conditions could hinder transportation to and from the peninsula. Power outages are also possible as a result of gale force winds, authorities said.
Navarro County, about 50 miles (80 km) south of Dallas, was one of the hardest-hit areas, inundating the tiny town of Powell with 20 inches (50 cm) of rain over 30 hours, according to meteorologist Brett Rathbun of Accuweather.
A flash flood swept a Union Pacific freight train off the tracks, pushing locomotives and some rail cars on their sides. No injuries were reported.
Authorities requested sandbags for evacuated homes and Interstate 45 was shut down in some spots in Navarro County due to rising waters, which reached one foot on the roadway in Richland.
Some 80 water rescues from vehicles, homes and businesses had been carried out in Navarro County since Friday, Sheriff Elmer Tanner said.
Aerial view of the Chabarim community in Colima State, Mexico on October 24, 2015 after the passage of hurricane Patricia. (Getty) Source: Getty Images
There were no confirmed deaths from the deluge, but in San Antonio, a woman reported that her boyfriend was swept into a drainage ditch as he walked his dog early Saturday. Officials said he was considered missing.
Saturday's rainfall led to the cancellation of about 100 flights at Dallas/Fort Worth International Airport, one of the country's busiest air hubs, according to tracking service FlightAware.
Retailers reported that locals made a run on supplies in anticipation of floods.
Thousands evacuated across Mexico
Thousands of residents and tourists had fled the advance of the storm, one of the strongest in recorded history, seeking refuge in hastily arranged shelters. There were no early reports of deaths and it appeared major damage was averted as Patricia missed tourist centers like Puerto Vallarta and the major cargo port of Manzanillo.
However, phone lines remain down where the storm hit in Cuixmala, the site of one of Mexico's most exclusive getaways located between Manzanillo and Puerto Vallarta, and it is unclear how bad the situation could be there.
Mowing down trees, flooding streets and battering buildings, Patricia hit land as a Category 5 hurricane on Friday evening before grinding inland. It moved quickly but lost power in the mountains that rise up along the Pacific coast and was downgraded to a tropical depression on Saturday morning as it headed through central Mexico.
In Puerto Vallarta, where 15,000 tourists had been hastily evacuated on Friday night, hotel workers began sweeping up the debris and removing boards from windows, as the sun peeked out of the clouds. The airport opened to start ferrying tourists back home and buses crowded the streets.
Away from the more populated areas, however, residents described awaking to a scene of chaos after a terrifying night.
"Around my house, the storm ripped up all the trees from the ground," said Eduardo Covarrubias, a restaurant-owner in the small town of La Union de Tula, about 125 miles (200 km) inland from Manzanillo. "It looked really ugly (when the storm arrived). Everyone was in real shock."
In its march north, Patricia was likely to make matters worse in Texas, which saw heavy rains overnight from a separate storm system that caused flooding powerful enough to knock over a freight train. Officials said moisture from Patricia would increase the intensity of rains swamping parts of the state by Sunday.
In Puerto Vallarta, most of the evacuated tourists had been able to return to their hotels on Friday night, officials said.
"Thankfully the damage wasn't so bad" in the Puerto Vallarta area, said Alhy Daniel Nunes, a spokesman for the Red Cross of Jalisco state.
Patricia's edges brushed Manzanillo port, a main exit for Mexico's car and mining exports, and port director Jorge Bustos said the facility was still closed, but he expected it to be open again by Saturday afternoon.
"We didn't have any major damage," he said. "Sure, gates, doors, some windows ... light roofs, that sort of thing, but nothing that was a risk to our operations."
