The region of Texas that suffered tremendous loss last week because of heavy rain and flooding is once again in danger of taking in more water. On Sunday morning, the National Weather Service issued a flash flood warning for the epicenter of the catastrophic Independence Day flooding event.

The National Weather Service warned that the Guadalupe River could surge to nearly 15 feet—5 feet above flood stage—by Sunday afternoon.

Here's what to know about the deadly flooding, the colossal weather system that drove it and ongoing efforts to identify victims.