Flash Flood in Williamson County, Texas

Across Round Rock and the northern sections of Williamson County, heavy rain fell much of the night with areas reporting up to 10 inches of rain. At the peak of the flooding there were 23 areas closed due to high water. Several homes along Brushy Creek were evacuated. Houses were damaged over the eastern portions along the Highway 79 corridor including Forest Creek, Hutto, and the County Road 123 area. Voluntary evacuations were called for in eastern Round Rock and Hutto. 88 homes were evacuated. Several swift water rescues were performed including 8 vehicle rescues. Overall 19 homes were affected by flooding rains in Williamson County with overall damages hit 1.1 million dollars in uninsured losses to public infrastructure.

Prolonged flow from the Gulf of Mexico produced a deep moist layer at the surface with precipitable water values two standard deviations above the mean on area soundings. An upper level trough of low pressure moved out of northern New Mexico and across the Texas Panhandle providing lift to produce showers and thunderstorms. A surface trough was the focus of training storms which produced heavy rainfall that led to major flooding across the Onion Creek and Blanco/San Marcos River watersheds.