Significant rainfall from storms caused flash flooding in parts of Montgomery County, Maryland, located north of Washington, D.C., on Saturday, trapping many in buildings and cars.

The National Weather Service urged people to avoid travel if a flash flood warning was in place for their area.

The Trump administration has changed course and is moving ahead with work to develop a new database that would provide Americans with precise estimates of their flash flood risk in a warming world.

At 11:58 a.m. on Friday, the NWS San Diego CA released an updated flash flood warning in effect until 2 p.m. for San Bernardino County.

FEMA’s maps are essential tools for identifying flood risks, but they have significant gaps that limit their effectiveness.

“If you’ve never seen water rise in front of you in minutes, it’s hard to conceive of how quickly that can happen—and how quickly your life and property can be at risk,” said Rachel Hogan Carr, executive director of the Nurture Nature Center, a nonprofit focused on flood-risk communication.

At 8:03 a.m. Sunday, doppler radar and automated rain gauges indicated the heaviest rain had left the warned area but smaller streams are still rising, the statement said.