HOUSTON (Reuters) - Heavy rains fuelled by the meeting of two strong storm systems, one the remnants of Hurricane Patricia, pounded south-eastern Texas triggering flash floods and derailing a freight train as the heavy weather descended upon Houston early on Sunday (Oct 25).
The National Weather Service predicted 15 to 30cm of rain for coastal areas including south-west Louisiana by Monday morning, exacerbated by tides up to 1.5m 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.
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 80km south of Dallas, was one of the hardest-hit areas, inundating the tiny town of Powell with 50cm 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.
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.