Flash Flood in Starr County, Texas

The Roma Fire Department reported that Arroyo Roma exceeded its banks, flooding parts of town with 1 to 3 feet of standing and flowing water during the pre-dawn hours of June 21st, 2018. The flooding was associated with the initiation of a thunderstorm system that would later cause significant flooding in western Hidalgo County, including the McAllen/Mission metropolitan region during the daylight hours later that morning. Measured and estimated rainfall was between 3 and 7 inches across southern and central Starr County. Estimated public damage, along with a standard doubling, left nearly $3 million in property and other damage (estimated).

Slow moving thunderstorm clusters dumped torrential rains over and near Rio Grande City during the early to mid evening of May 4th, with storm totals likely between 4 and 5 inches across the area. A combination of reports from law enforcement, emergency management, and social media indicated dangerous flooding in parts of the city, with several water rescues and minor flooding reaching into several homes on the east side of town. Social media photos and discussion reported a yard with 1 to 2 feet of water flowing through it at around 8 PM CST; water rescues from stranded vehicles were reported along US 83 on the east side of town at around 8:55 PM CST, and another vehicle was reported stranded in floodwaters at the intersection of Flores and Monroe Street, also on the east side of town. The NWS cooperative observer reported 4.28 inches with the event, most falling within two to three hours.

Only a few hours after rains had tapered off Starr County, another complex of thunderstorms crept into the already flooded areas of southwestern portions of the area, and an additional 4 inches or more fell in or near areas impacted by the original floods during the evening of the 22nd, causing perhaps up to eight or nine neighborhoods to have a number of road closures, as well as homes having water pushed into them by passing vehicles. After the rains subsided, the event evolved into an area wide flood which continued well into the night, requiring additional water rescues.