Heavy rain dropped by Hurricane Hanna caused flash floods in South Texas on Sunday. Radar estimates of the rainfall indicated that 10-15 inches (3 to 5 meters) of rain fell on parts of Lower Rio Grande Valley during the passage of former Hurricane Hanna. A weather station in McAllen, Texas measured 8.24 inches (209 mm) of rain. Flash Flood Warnings were in effect for West Central Cameron County, Southern Hidalgo, Southwest Jim Hogg County, and Central Zapata County. The Arroyo Colorado in Harlingen, Texas rose from 5.2 feet (1.6 meters) to 20.72 feet (6.3 meters) and it was still rising.
Rain was still falling over parts of the Lower Rio Grande Valley even though the center of former Hurricane Hanna had moved over northeastern Mexico. At 5:00 p.m. EDT on Sunday the center of Tropical Depression Hanna was located at latitude 25.6°N and longitude 100.6°W which put it about 35 miles (55 km) west-southwest of Monterrey, Mexico. Hanna was moving toward the west-southwest at 9 m.p.h. (15 km/h). The maximum sustained wind speed was 35 m.p.h. (55 km/h) and there were wind gusts to 45 m.p.h. (75 km/h). The minimum surface pressure was 1002 mb.