Further storms are forecast to add to the misery of the residents of Houston, where at least one person was killed and more than 1,000 homes flooded after a major storm.
Power cuts were widespread in the Texas city, with more than 70,000 customers losing power during the storm.
Houston Intercontinental Airport reported its wettest day April day on record as central parts of the city were soaked by 200mm of rain, and some of the outer suburbs in the west recorded as much as 450mm.
This is nearly five times the amount of rain that is expected in the entire month of April.
This type of deluge is highly unusual for the southern state, and believed to be the worst flooding since 2001 when Tropical Storm Allison stalled over the region for several days.
Al Jazeera’s meteorologist Steff Gaulter explains, "The rains were brought by a cluster of thunderstorms which joined together. This kind of system is known as a mesoscale convective system, and will often persist for a number of hours."
The region remains in the firing line for storms over the next few days. More severe storms are likely across eastern Texas, which could bring damaging gusts of winds and more torrential rain.
Source: Al Jazeera and agencies