Flash Flood in Starr County, Texas

Torrential rains estimated up to 2.5' in 30 to 45 minutes in Roma filled

up culverts near Arroyo Roma, and an estimated additional 1 to 2' following the

supercell overflowed drainage, resulting in a flash flood in the hilly parts of the city. Flooding began around 1 AM CST, and persisted until just after 4 AM CDT (3 AM CST), peaking at 320 AM CDT (220 AM CST).

The combination of intense rainfall/rainfall rate, hilly terrain and poor

drainage, and rapid runoff due to prior extreme drought led to the flash flood

in Roma. Fast flowing water in streets was between 2 and 3 feet high at

the peak.

The floodwaters pulled up pavement from several neighborhood streets in

the city. Up to 30 homes reported water levels inside, ranging from 6' to 1

foot, during peak flooding. A 2- to 3-foot deep hole was scoured out by the floodwaters next to a home near the intersection of Rau-Con St. and Bravo Ave., and several vehicles parked in driveways near the fast-flowing water had grass and mud left behind, up to 2 feet high on the sides of the vehicles.

A supercell thunderstorm developed just off the plateau of the Sierra Madre and moved along the Rio Grande along the Zapata/Starr Countyline before moving into and across southern Starr County between 1126 PM March 7 and 1204 AM CST March 8. This severe thunderstorm went on to produce a persistent wet microburst, which produced wind-driven large hail damage and wind damage near and around Rio Grande City and Roma. Three people were injured in their car after a gas station canopy collapsed onto their vehicle in east Rio Grande City.

A second wave of heavy rainfall moved along the Rio Grande between Roma and Rio Grande City between midnight and 2 AM, pushing already filled culverts and arroyos over their limits and produced a significant flash flood in Roma early on March 8th.