Life-threatening flash flood threat targets Texas, Louisiana this week

Houston and the Texas coast were bracing for a dangerous burst of rain that could turn streets, bayous and low-water crossings into traps as a disturbance over northeastern Mexico threatened to drift back over the northwestern Gulf late Tuesday or Wednesday. The National Hurricane Center said the system had a 40% chance of tropical development in 48 hours and a 50% chance in seven days, but warned that flooding danger would be serious even if no tropical cyclone forms.

The highest flash-flood risk sat in southern and coastal counties across southeast Texas, including Houston, Harris County and Galveston, where the National Weather Service in Houston/Galveston kept a Flood Watch in effect through Thursday morning. That area was placed in a Level 3 of 4, Moderate excessive-rainfall risk, and forecasters said rainfall could become intense enough to overwhelm drainage and quickly inundate vulnerable neighborhoods. ABC13 Houston called Monday and Tuesday Weather Alert Days, with rainfall rates that could exceed 4 inches an hour and storm totals of 4 to 7 inches through Wednesday, with isolated pockets above 10 inches.

The danger was not limited to one state line. The National Weather Service office for New Orleans and Baton Rouge said excessive rainfall could produce locally considerable flash flooding across South Texas, the western Gulf Coast and the lower Mississippi River Valley through Thursday, with 5 to 10 inches of rain expected in its forecast area. That puts New Orleans, Baton Rouge and surrounding communities in a stretch of repeated heavy rain that can quickly close roads, strand drivers and put low-lying areas at risk of water rescues.

The timing matters. Forecasts showed the most dangerous window building late Tuesday into Wednesday, when the disturbance could briefly organize over the Gulf and keep feeding bands of heavy rain back into already saturated ground. For communities that have already been soaked by earlier rounds, each additional downpour raises the chance of rapid runoff, flooded intersections and neighborhoods cut off from emergency access.

Texas Gov. Greg Abbott activated state emergency response resources on June 11, directing the Texas Division of Emergency Management to stage rescue and medical assets before the worst of the rain and urging residents to review emergency plans and check road conditions. The warning carries a painful memory in Houston, where Tropical Storm Allison in June 2001 dumped 15 to 35 inches of rain in parts of the region, killed 22 people in the Houston area, damaged more than 48,000 homes and flooded more than 70,000 automobiles, becoming the costliest tropical storm on record in Texas and the United States.