Flooding triggered by heavy rains in and around Houston has killed at least seven people and prompted mass rescues, authorities from America's fourth-largest city said Tuesday.
A flash flood watch will be active in the Texas city through late Wednesday, the US National Oceanic and Atmospheric Administration said, warning of "widespread showers and thunderstorms" with up to four inches (10 centimeters) of rainfall.
"Most drown victims occur in vehicles... Turn around, don't drown," it said in a bulletin urging people to avoid travel in flooded areas.
"Flash flooding is a very dangerous situation."
Cars were partially engulfed on roadways that had turned into swollen rivers.
Three men and two women were found dead in vehicles on flooded roadways in Harris County -- home to the Houston metropolitan area -- with another man found dead in neighboring Waller County.
The Houston Chronicle reported an additional fatality in nearby Austin County.
Texas Governor Greg Abbott has declared a state of disaster in nine counties, unlocking state resources to handle the emergency.
Harris County said first responders there have rescued 1,821 across the area, warning it expected more deaths and flooding victims.
Three shelters have been opened in the county, which has staffed its Emergency Operations Center on a 24-hour basis until further notice.
Houston International Airport experienced its second wettest day ever recorded on Monday, the National Weather Service said.