The flash floods in central Texas in July 2025 were caused by extreme rainfall stemming from the remnants of Tropical Storm Barry, combined with warm, humid air from the Gulf of Mexico and thunderstorms moving into the region from the west. The region’s steep hills and rocky terrain funneled the rain into low-lying areas. Runoff was hastened by the effects of a period of extended drought, which had hardened much of the soil in the region.