On 12 June, San Antonio, Texas, experienced severe flash flooding triggered by a slow-moving thunderstorm system exhibiting “training,” where storms repeatedly passed over the same area. Driven by an upper-level trough moving east through Texas and fuelled by record-warm Gulf of Mexico sea surface temperatures, the result was record breaking intense rainfall.
San Antonio International Airport recording 162 mm (6.37 inches) in 24 hours, including 142.2 mm (5.6 inches) in three hours and nearly 101 mm (4 inches) in a single hour. This surpassed the previous June daily record of 83 mm (3.26 inches) set in 1973 and was classified as a 1-in-50 to 1-in-100 year rainfall event. Localised areas like the Far West Side, Helotes, and Medina, Comal, Hays, and Guadalupe counties received 178–203 mm (7–8 inches). To give some context to the exceptional nature of this event, San Antonio’s average June rainfall is about 76 mm (3 inches).
San Antonio’s location in “Flash Flood Alley” near the Balcones Escarpment, where warm, moist Gulf air gets trapped, amplified precipitation. The region’s thin soil over bedrock and urban infrastructure, including overwhelmed drainage systems and low-water crossings, exacerbated runoff and flooding.
The rapid rise of the San Antonio River from 0.9 m (3 feet) to over 7.6 m (25 feet) in two hours caused catastrophic flooding. There have been eleven confirmed fatalities with many victims swept away in vehicles, particularly at Northeast Loop 410 and Perrin Beitel Road. Over 70 high-water rescues were conducted, including a notable incident at Beitel Creek and Loop 410, where 19 people were swept into floodwaters, and 10 were rescued, some from trees 1.6 km (1 mile) downstream. Dozens were hospitalized with injuries such as hypothermia and fractures. Search and rescue operations continued the next day focusing on areas like Salado Creek near Perrin Beitel and Leon Creek near Highway 90 and Callaghan Road, with several people still missing.
The floods caused widespread infrastructure damage, with multiple roadways, including Vicar Drive at Beitel Creek and Old O’Connor Road, washed out or closed indefinitely. Approximately 30,000 residents experienced power outages, some lasting over 24 hours. The Olympia Hills Golf & Event Centre suffered bridge failures and debris flows and is now closed for at least three days. Businesses in low-lying commercial areas reported significant flood-related closures and losses.
By the end of 13 June, the National Weather Service (NWS) reported that floodwaters were moving downstream into the Coastal Plains, with minor to moderate flooding forecast along the San Antonio River and Cibolo Creek in Wilson along with Karnes counties through the weekend. The NWS emphasized the ongoing danger, urging residents to “turn around, don’t drown” to avoid flood-related risks.
