Flash flooding near St. Louis High School in Lake Charles, LA on October 18th, 2006

(Picture courtesy of Sarah Allen, Journeyman Forecaster WFO Washington D.C.)

Since Hurricane Rita, rainfall has been a scarce commodity across Southeast Texas and Southwest Louisiana.  A few weather systems have brought some rainfall during that time, including a few very heavy rain events over Southeast Texas and extreme Southwest Louisiana.  However, the series of heavy rainfall events from October 15th through October 22nd signifies a change in the weather pattern across the region, partly in response to developing El Ni�o conditions in the Pacific Ocean.

These series of strong storm systems were the result of warm fronts moving north from the Gulf of Mexico, pulling tropical moisture into the area.  This moisture combined with increasing upper level moisture from southwesterly winds aloft.  As these warm fronts shifted north, upper level disturbances traveling in the upper flow aided in the development of widespread showers and thunderstorms during the seven day period.

The first in the series of storm systems brought initially welcome rainfall on Sunday, October 15th, since the area was experiencing abnormally dry conditions.  However, the continued heavy rainfall on Monday October 16th saturated soils across much of the region, leading to creeks and bayous filling with water runoff.  Serious flooding began in many locations with numerous road closures and water approaching homes.  Southeast Texas and West-Central Louisiana were especially hard hit as continuous bands of heavy rainfall moved repeatedly across Hardin, Tyler, Jasper, and Newton Counties, as well as Vernon Parish.

Rainfall totals from this first storm system ranged from only one inch in portions of South-Central Louisiana, to as high as 10-15 inches in a 20 mile wide band from Sour Lake to Kountze to Jasper to Toledo Bend Dam to Anacoco.  This heavy rainfall caused minor to moderate river flooding on several rivers in the area.

This first storm system also was unusually strong for October, with a deep area of low pressure that brought widespread high winds and severe weather to the region.  This area of low pressure helped spawn several severe thunderstorms with tornadoes across Southeast Texas and Louisiana, causing some damage to homes.

The second and third storm systems in the series also brought widespread additional rainfall to Southeast Texas and much of Louisiana, as well as more severe weather in some locations.  Rainfall totals from these two systems once again ranged from as little as one inch in areas near the coast, to as much as 8 inches in parts of Southeast Texas, Central Louisiana, and Southwest Louisiana.  Unlike the previous system, heavy rainfall also fell in portions of South-Central Louisiana.  All of this additional rainfall led to moderate and major river flooding on numerous rivers in Southeast Texas and western Louisiana.  Some rivers reached their highest levels ever recorded, leading to widespread flooding of roadways, homes, and businesses.

Overall, this series of storm systems was one of the most active severe weather and flooding events in the history of the National Weather Service office in Lake Charles.  Numerous weather watches and warnings were issued over the seven day period from October 15th through October 22nd.