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.

"Flood waters have receded. Flooding is no longer expected to pose a threat. Please continue to heed remaining road closures," according to the National Weather Service.

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.

Several historic and deadly flash flooding events have occurred in the U.S. just within the month of July alone. Experts talk about what factors are increasing the risks.

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.

LOUISVILLE, Ky. (WAVE) - An ALERT DAY is in place this evening as clusters of thunderstorms move into the region. Some storms may produce strong gusty winds. Flash flooding remains the top concern, especially along the I-64 corridor through the overnight hours.

“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.