The danger has extended to Travis, Williamson and Burnet counties, where very dangerous flash flooding is ongoing Saturday morning. Between 5 and 12 inches of rainfall has fallen there, the weather service said, calling it a "Particularly Dangerous Situation with life-threatening flash flooding."

Flash-flood warnings and watches remained in effect for parts of Central Texas, dimming hopes that more survivors would be found.

At least 51 people are dead and 27 campers are missing after flash floods tore through Texas, prompting massive rescue efforts and leaving families desperate for answers. NBC News' Ryan Chandler reports.