Even when floods can be anticipated, communicating their severity to the public is a tall order. Because flash floods are very localized, even neighborhood-level warnings may seem like false alarms to some residents, leading to what the journalist Zoë Schlanger has dubbed “ alert fatigue .”

Today, 17 million are under flood alerts across the Gulf Coast and in the Mid-Atlantic, and 19 million are under heat alerts across the Mid-Atlantic, southern Florida and Mississippi Valley.

Thousands of flash flood warnings have been issued across the country and the number of flash flood emergencies is near-record, too.

A flash flood warning was issued by the NWS Fort Worth TX on Monday at 2:30 a.m. in effect until 5:30 a.m. The warning is for Johnson, Bosque and Hill counties.

A spokesman for Camp Mystic, the Texas enclave devastated by a July 4 flash flood, is raising concerns about communication failures during the disaster.

Sunday morning recovering efforts were suspended in Kerr County due to heavy rainfall and a new flash flood warning issued for the Hill Country.

"It's not community to community. It's a national system," Sen. Maria Cantwell said on "Face the Nation with Margaret Brennan."