Heavy rains fueled by the meeting of two storm systems, one the remnants of Hurricane Patricia, pounded southeastern Texas, triggering flash floods and derailing a freight train as heavy weather descended on Houston early on Sunday.

The National Weather Service predicted 15 to 30 cm of rain for coastal areas, including southwest Louisiana, by Monday morning, exacerbated by tides of up to 1.5 meters and wind gusts.

The rain systems were intensified by Patricia, which was 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 braced for the impact. They included Houston, the state's second-most populous metropolitan area with 6.1 million people.

Mayor Annise Parker warned residents to stay away from wet roads after dark and to be aware of flash floods, which the National Weather Service said were occurring in the city early on Sunday. No one was reported hurt, but several motorists were stranded.

Flash flood warnings were in place until 4 am for eight southeastern Texas counties. Among them are Harris County, which includes Houston, and Galveston County. Some areas could get more than 30 centimeters of additional rain.

Officials urged vigilance, reminding residents of deadly past flooding. A series of storms in May triggered floods and led to 21 deaths.

"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."

In Galveston, authorities urged voluntary evacuation of the elderly and residents with medical issues on the Bolivar Peninsula near Galveston Bay. The storms could hinder transportation to and from the peninsula. Power outages were also possible as a result of gale force winds, authorities said.

(China Daily 10/26/2015 page10)