National Weather Service Weather Forecast Office

Introduction

Between April 12th and April 17th 2010, a widespread heavy rain and flooding event occurred across much of South Texas. The hardest hit areas were Jim Wells, Duval, McMullen, Live Oak, Bee, Victoria, western Kleberg, western Nueces, eastern La Salle and eastern Webb counties. Many of these areas received between 5 and 10 inches of rainfall during this six day period. A few locations in northern McMullen and northern Jim Wells counties recorded more than 11 inches of rainfall for the entire event. The widespread and persistent heavy rainfall caused many streams and creeks to overflow their banks. Dangerous flash flooding was the result and required several high water rescues of stranded motorists. 30 flash flood farnings were issued for this event which is more than all of the total number of flash flood warnings issued for 2009.

Besides the heavy rain and flooding, severe weather occurred on April 17th across Nueces and Kleberg counties. A supercell thunderstorm developed in western Nueces county and tracked southward through western Kleberg county during the afternoon and evening on the 17th. Nickel size hail and a 1/2 mile long track F0 tornado were produced by the supercell thunderstorm. On April 18th, a weak seabreeze developed across Calhoun county in the late afternoon and early evening. Sufficient moisture and instability was present to form showers along the seabreeze. As the updrafts within these developing showers stretched, several funnel clouds developed in the vicinity of Port Lavaca.

The heavy rain and flooding was triggered by many weather factors. Deep moderate to strong east to southeast winds extending upwards to at least 10000 feet aided in bringing in copious Gulf moisture. Several upper level disturbances interacted with this deep Gulf moisture. Slow steering currents in the upper levels of the atmosphere aided in the same areas receiving heavy rain.

Radar Loops

April 12

April 13

April 14

April 15

April 15 night

April 16

April 17

Local Storm Reports

Storm Total Precipitation and Rainfall Reports

Photos

Videos

Creek near Oakville under I-37 Frontage Road

Creek along Highway 72 east of I-37

Coast Guard Video - Jim Wells County

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