Millions in Central Texas remain under threat of flooding as the region enters its fourth consecutive day of rain.
Among those under watch are areas already devastated over the Fourth of July weekend, when more than 80 people died in separate flash flooding events.
One event along the Guadalupe River on Friday battered Kerrville and the all-girls Camp Mystic, which sits on the riverbank. On Monday, the camp confirmed the deaths of 27 campers and counselors. In total, 70 deaths were reported in the region, and more than 850 people were rescued.
Another flash flood struck the San Gabriel River and Austin area early Saturday, where at least eight people died and 18 remain missing in Burnet, Williamson and Travis counties.
National Weather Service issues flood watch for Central Texas
The National Weather Service office in Austin has issued a flood watch across the Hill Country and along the Interstate 35 corridor through early Monday evening.
"There remains a threat of flash flooding from slow moving heavy rains overnight and through the day on Monday somewhere over the watch area," the advisory states.
The weather service warns of the potential for 2 to 4 inches of rainfall — with isolated amounts of up to 10 inches — from overnight showers and possible continued development throughout the day in the watch area.
"Difficult to pinpoint exact locations where isolated heavier amounts will occur," the advisory states. "Rainfall rates will be very intense in the heaviest showers and storms. Any additional heavy rainfall over hardest hit areas of the past few days will lead to rapid runoff and flash flooding."
While the probability of precipitation continues across Central Texas into Tuesday and Wednesday, the weather service forecasts drier and warmer conditions by Thursday, with chances dropping to 5% or less on Friday.
Warning vs watch: What is a flash flood warning?
A flood watch is issued when conditions are favorable for flooding, according to the NWS. It doesn't guarantee flooding will occur, but it means flooding is possible.
A flash flood warning is issued when a flash flood is imminent or already happening, USA TODAY reported. If you’re in a flood-prone area during a flash flood warning, move to higher ground immediately.
Flash floods can develop within six hours of heavy rain, dam or levee failure. They can uproot trees, destroy buildings and bridges and trigger mudslides — sometimes with water rising over 40 feet as witnessed along the Guadalupe River flooding, which rose by 40 feet in less than two hours.
Flash floods can even occur in areas that aren't receiving rain, the NWS warns.
Map: Texas weather watches and warnings
Map shows real-time weather watches and warnings by county based on advisories from the National Weather Service.