USGS storm summaries)
October 17 to 18, 1998
Up to 30 in. of rainfall occurred in a 2-day period--about
5,000 square miles in parts of 19 counties received at least 8
in. of rain. Thirteen streamflow-gaging stations in the Guadalupe
and San Antonio River Basins recorded peak discharges equal to
or greater than the 100-year peak and record-breaking peak discharges
were recorded at 11 of the stations. read
Deaths and Damage: Thirty-two lives were lost and property
damage was estimated to be approximately one billion dollars.
Max. Precipitation: 30.00 in. (Hays Co.) 22.00 in. (Comal
Storm Center(s): Hays Co., San Marcos Comal Co.
References: Slade and Persky, 1999
The storms produced large volumes of runoff and as many as four
flood peaks at each of many streamflow-gaging stations in the
Brazos, Colorado, and Guadalupe River Basins. Record flood stages
occurred at sites on the Medina River, San Antonio River, Sabinal
River, and Nueces River. For the first time since it filled in
1968, Canyon Lake (northeast of San Antonio) poured over its spillway,
adding to the flooding in the Guadalupe River. Emergency managers
also were concerned about the 90-year-old dam at Medina Lake (west
of San Antonio). Medina Lake topped its spillway and rose to within
18 inches of the top of the dam. Areas downstream from the dam
were evacuated as a precaution to the fear of dam failure.