Flood Sensors Questioned at Crossings

Flood sensors are supposed to answer one very simple question fast — is this road safe to cross right now? In San Antonio and Bexar County, that answer has gotten murky. During the latest round of heavy rain on May 1, some sensors on the public flood map showed up as inactive again, even as water risks were rising. That turned a technical maintenance issue into a very human one — because this is a region still living with the memory of deadly flooding last June. ### What are these sensors supposed to do? They sit at low-water crossings and feed data into the local flood-warning system. When water rises, the system is meant to help officials decide where to barricade roads, trigger warning lights, and update the public-facing BexarFlood map that drivers are told to check during storms. Basically, they are the early-warning layer between a normal road and a dangerous one. ### What went wrong this time? On Friday, May 1, as rain kept falling across the San Antonio area, KSAT noted that some high-water sensors tied to Bexar County’s flood map did not appear to be working. That mattered because forecasters were warning of 2 to 4 inches of rain in many spots, with isolated totals up to 6 inches. A sensor that goes dark on a dry day is one thing. A sensor that goes dark during a flood threat is the real problem. ### How many sensors are down? The clearest number comes from a News 4 investigation published April 27. It found more than a dozen sensors inactive or offline across Bexar County. The station had reported the same thing on April 22, and some of the dead sensors had been out for a long time — one along Bandera Road since August 2025, another in Helotes since 2023, and one at Jungman Road near the Medina River since 2019. ### Is this just missing data, or actual bad behavior? Turns out it is both. News 4 found one crossing that had been inactive since January where warning lights were flashing even though no water was on the roadway, while the crossing arm never lowered. That is worse than silence. A dead sensor leaves you blind. A glitchy one can tell drivers the wrong story. ### Why are repairs taking so long? The River Authority says the causes range from vandalism and insects damaging equipment to communication failures between sensors and the network. There is also a coordination problem — multiple agencies share responsibility for different crossings, which slows repairs and muddies all talking in terms of “a few more months” for some fixes. ### Why does this hit so hard in San Antonio? Because this is not an abstract resilience story. On June 11 and 12, 2025, devastating flooding hit San Antonio and Bexar County, and officials later issued a joint disaster declaration. Thirteen people were killed in the broader flooding disaster, and one of the offline locations identified by News 4 was Vicar Drive — the crossing where 11 people were swept away in June 2025. ### So what is being built now? Bexar County, the City of San Antonio, and the San Antonio River Authority have been rolling out the NextGen Flood Warning System, a roughly $20 million to $21 million upgrade approved in August 2025. The plan is bigger than a few replacement sensors — it includes predictive modeling the new one is being built. ### Bottom line? San Antonio is trying to build a smarter flood-warning network after a deadly year. But the latest rain showed the awkward middle stage clearly — the region is asking people to trust a system that still has blind spots, false signals, and repairs that are not finished yet.