Flash Flooding in Texas, June 30, 2002

Toward the end of June, 2002, a trough of low pressure, featuring a cold-core low on its north end, moved inland from the western Gulf of Mexico across the Texas Coast. This system, with cold temperatures aloft and a rich moisture field and very warm temperatures in the lower levels of the atmosphere, began to produce widespread showers and thunderstorms across central Texas. On the 29th of June, the activity produced general rain amounts of less than 1 inch, with isolated totals between 3 and 4 inches over parts of Guadalupe, Hays, Bandera, Gonzales and DeWitt Counties. No flooding problems were indicated, but a long-standing drought had begun to weaken, and soils along and east of the I-35 corridor were starting to saturate. The shower and thunderstorm activity that developed on June 30th was much more widespread and significant. The activity initiated over the Hill Country shortly after midnight on the 29th and spread southeastward to cover most of South Central Texas. An axis of heavier rain ran along much of the I-35 corridor from Marble Falls to Blanco to Boerne to San Antonio to Pleasanton and southward beyond Tilden. In this area, the average rainfall was between 3 and 5 inches, with isolated totals to near 9 inches. Area soils were completely saturated within a few hours, and by mid-afternoon, most streams and creeks were running full. Widespread flash flooding began just before sunrise and continued well into the afternoon period in the counties of Burnet, Gillespie, Blanco, Kerr, Bandera, Kendall, Hays, Comal, Bexar and Guadalupe. Damage was reported to roads and bridges across this ten county area. There were no injuries and no loss of life.