Flood watch widens in South Texas as catastrophic rain looms

The National Weather Service warned Tuesday that parts of South Texas faced “considerable to locally catastrophic flash flooding” as intense storms kept dropping heavy rain and more was expected through Wednesday and Thursday. In the most vulnerable areas, forecasters said another 10 to 20 inches could fall, with 2 to 6 inches more likely across much of the broader flood watch.

The active Flood Watch stretched into Thursday evening for the southern Edwards Plateau, the Rio Grande, the Winter Garden region, the Hill Country and the I-35 corridor. Forecasters said flash flooding could develop anywhere inside that watch area, not just in the hardest-hit pockets, a warning that reflected how quickly repeated rainfall can overwhelm creeks, roads and drainage channels already saturated by earlier storms.

The Weather Service also said the week’s total rainfall could reach more than half of a normal year’s rain in some locations. Its forecast discussion warned that significant to locally catastrophic flooding could continue, with additional rainfall totals of 3 to 6 inches expected through the rest of Tuesday night in the Texas Hill Country and localized amounts above 10 inches still possible. Storms were expected to linger over the Hill Country and western San Antonio suburbs, where runoff can build fast on already soaked ground.

Texas has long been exposed to that kind of rainfall threat, and federal rainfall studies have shown the state’s 100-year rain estimates have increased as decades of additional weather data were added. That means storms once considered rare are now understood to arrive more often than older planning assumptions suggested, a shift that carries direct consequences for emergency managers, road crews and communities along fast-rising waterways.

The warning lands against fresh memory in Texas Hill Country, where a July 4 flood killed more than 100 people, including many summer campers. During that disaster, the Guadalupe River rose 26 feet in 45 minutes, a scale of rise that showed how little time residents can have when thunderstorms stall over vulnerable terrain. Tuesday’s forecast left the same central message in place: in South Texas, repeated rain on saturated ground can turn a flood watch into a life-threatening emergency with little warning.