Schools were closed, roads were flooded and residents were told to evacuate as heavy rain continued to lash the Houston area and other parts of South Texas on Friday, placing thousands of people under flood warnings and leaving many without power.

Flash flood warnings were issued early on Friday for more than 840,000 people in Harris, Liberty and Montgomery Counties. About 15,000 customers were without power in those three counties on Friday, according to PowerOutage.us, which aggregates data from utility companies across the United States.

The prospect of more rain came after a disaster declaration was issued on Thursday in Harris County after the San Jacinto River, on the outskirts of Houston, was swelling. People in neighborhoods near the east fork of the river were ordered to evacuate.

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