Noem said the rapid delivery of funds to Texas resembled the “state block grants” model Trump has promoted. It’s an idea that would replace FEMA’s current system of reimbursing states for response and recovery expenses at a cost-share of at least 75%.

Mr. Trump said his administration was working with state and local officials and that Department of Homeland Security Secretary Kristi Noem would be arriving in Texas shortly. DHS oversees the Federal Emergency Management Agency.

Officials said more than 850 people had been rescued after a sudden storm dumped up to 15 inches of rain across the region.