Flash Flooding Alerts Issued After Heavy Central Texas Rain

AUSTIN, TEXAS — A flash flood warning issued for the area around Lake Travis late Tuesday will remain in effect until 5 a.m. Wednesday — not in anticipation of more heavy rain but over fears of potential overflow at the body of water now at historically high levels.

Relentless rainfall that began late Monday that continued into Tuesday wreaked havoc in their wake, prompting the state's governor to issue emergency declaration for 18 Central Texas counties. While the rain finally subsided by Tuesday afternoon, the heightened levels at area waterways — chiefly the massive man-made Lake Travis reservoir — now pose a threat given their elevated levels of water volume bolstered by the heavy rainfall.

By late Tuesday, Lake Travis was 120 percent full with levels of 691.89 feet, according to Lower Colorado River Authority officials. Water from Lake Buchanan was let out as emergency officials dealt with Tuesday's deluge, but the measure had the effect of further bolstering Lake Travis water levels.

Given the resulting threat those high water levels now pose, evacuations have taken place in at least two low-lying areas fronting Lake Travis. The island of Lago Vista fronting Pace Bend Park was evacuated, according to reports, as has Graveyard Point.

The region remains saturated from recent heavy rainfall, forecasters explained. Additional moderate to heavy rainfall will result in more rapid runoff leading to new river rises in addition to flash flooding, officials added.

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Flash Flooding Alerts Issued After Heavy Central Texas Rain

A flash flood warning is issued by the U.S. National Weather Service when a flash flood is imminent or occurring in the warned area. A flash flood is a sudden, violent flood after a heavy rain, or occasionally after a dam break.

This potential scenario could be seen locally. As evening fell in the calm after the storm, Lake Travis continued to rise as it worked its way to major flood stage. Should the lake reach 714 feet — something that's never happened in the history of the Colorado River reservoir since its 1942 construction — it would overflow its banks.

Burnet County also is part of the flash flood warning, according to the National Weather Service (NWS).

Flash flooding is possible Tuesday night and into Wednesday night and Thursday, NWS forecasters said. And, yes, officials added, the rain will continue but primarily in west central Texas and further south. After a summer marked by drought-like conditions, Central Texas has gotten exponentially more rain that was ever needed even after such a parched summer. The Central Texas region has not only got pelted since late Monday, but experienced an unusually rainy September.

Despite the liquid abundance, the region is now poised to receive even more precipitation.

"Plenty of moisture along with a series of upper level disturbances will result in continued moderate to heavy rainfall across portions of south central Texas through Thursday," officials wrote. "For tonight [Tuesday, Oct. 16] into Wednesday morning, the focus for heavy rainfall is expected to remain primarily across Val Verde and Edwards counties. Rainfall chances continue on Wednesday, but it appears the higher rainfall amounts will remain over west central Texas."

Yet it's the runoff from this week's rain that poses a clear and present danger, according to forecasters: "However, runoff from this rainfall could still pose a flood threat across Guadalupe, Llano and Colorado River basins. Late Wednesday night into Thursday, another surge of moisture will move into south central Texas. This will likely bring additional moderate to heavy rainfall to much of south central Texas, especially for areas along and west of the I-35 corridor."

Other surrounding counties are under a flash flood watch in effect through Thursday evening, according to forecasters. The affected area is a portion of south central Texas, including the counties of Bandera, Blanco, Burnet, Edwards, Gillespie, Kendall, Kerr, Kinney, Llano, Maverick, Medina, Real, Uvalde, Val Verde and Zavala, according the the NWS. Additional rainfall amounts of 1 to 2 inches of rain are possible, according to forecasters, with isolated spots getting close to 4 inches.

Portions of west central Texas also remain under a flash flood watch through Thursday evening. Counties covered in the flash flood watch include: Brown, Callahan, Coke, Coleman, Concho, Crockett, Irion, Kimble, Mason, McCulloch, Menard, Runnels, San Saba, Schleicher, Shackelford, Sutton, Taylor and Tom Green.

As defined by the National Weather Service, a flash flood watch is issued when conditions are favorable for flash flooding in flood-prone areas, usually when grounds are already saturated from recent rains, or when upcoming rains will have the potential to cause a flash flood.

Rainfall amounts between 1 to 3 inches will be commonplace across the west central portion of the state, forecasters predicted. Some areas in that west central portion of the state could see up to 4 inches, officials added. "High rainfall amounts, along with saturated soils, will produce rapid runoff, and low water crossings and city streets may flood quickly," officials said. "Creeks and streams may fill with swiftly flowing water."

As always, motorists should visit ATXfloods.com to see which streets are closed due to high water on area roadways. As of early Wednesday, the site indicated, 165 crossings were closed. That's down from the peak of the storms when more than 200 roads were closed, but could fluctuate upwards in the event of more rain later Wednesday. Another site to check road conditions is drivetexas.org.

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