The "Memorial Day Flood": a look back

Massive 1981 flood in Austin offers lessons to public on flood safety

​By John Williams

As Central Texas suffers through one of its most intense droughts, it's difficult to imagine a Sunday evening 30 years ago this week, when heavy rains triggered a massive flood in Austin that longtime residents still remember as the "Memorial Day Flood."

The flood, which occurred May 24, 1981, during the Memorial Day weekend, was one of the worst to hit Austin. Rains of up to 11 inches in a three-hour period caused creeks to flow out of their banks, creating 15-to-20-foot walls of water at some locations, according to one account. The storm's worst impact was along Shoal Creek in Central and downtown Austin.

The storm transformed Shoal Creek, which usually has little or no streamflow, "into a killer," as the Austin American-Statesman put it in a story published two days later. The creek swept through several Austin neighborhoods, saving its worst for the downtown district, where it ripped into the storefronts of car dealerships and furniture and music stores. According to the Statesman story, at least 565 cars in dealership lots were destroyed or damaged, and one piano from a music company was seen floating down Town Lake (now known as Lady Bird Lake).

By the time the creeks had returned to their banks, the floodwaters had caused at least $35 million in damages (almost $83 million in today's dollars, according to the Inflation Calculator website) and 13 fatalities, six of them at low water crossings, according to news accounts.

And it was the worst flood to hit Austin in several decades. "It was a '100-year' flood," said LCRA Chief Meteorologist Bob Rose, referring to a hydrological term that describes a magnitude of catastrophic flooding. "It was one of the many intense storms Central Texas receives from time to time – only this one happened to fall over an urban area."


LCRA was powerless to control floodwaters

The brunt of the storm occurred downstream of Mansfield Dam, and floodwaters poured into Lake Austin and Town Lake, causing the two lakes to rise rapidly.

That presented a double whammy to LCRA: It couldn't capture the floodwaters because they were downstream of Mansfield Dam, the linchpin in LCRA's chain of Highland Lakes and dams for managing floods.

Worse, there was little that LCRA could do to manage the rapid rises on the lakes downstream of Mansfield Dam.

"Folks on Lake Austin were calling us in a panic to open the floodgates at Tom Miller Dam (which forms Lake Austin) to keep their homes from being flooded," remembers Bill West, who managed LCRA's System Operations Control Center at the time. "And downstream of Tom Miller, folks were calling us to keep the gates closed."

There was no easy option for West - or LCRA.

"Unlike Lake Travis, the lake formed by Mansfield Dam upstream, Lake Austin and Town Lake have no room to store floodwaters," explained West, who today is general manager of Guadalupe-Blanco River Authority in Seguin. "That means if floodwaters are flowing into Lake Austin, LCRA's only option is to open floodgates to pass the water – unless there are problems downstream."

And there were problems downstream at Town Lake, which was receiving the floodwaters from the rampaging Shoal Creek and other tributaries. The dam that regulated Town Lake, Longhorn Dam, was operated by the City of Austin, outside of LCRA's system. By opening floodgates at Tom Miller Dam, West risked dumping additional floodwaters into the swollen lake and making a bad situation worse.

West watched the situation nervously. "We had a guy on top of Tom Miller Dam, waiting for instructions on whether to open any gates," West recalled.

As unpleasant as were his options, West explained that allowing Lake Austin to rise into lakeside residents' property was the better choice in terms of public safety. "If you have to decide between inundating or washing people away," he said, "people normally have time to get out of rising water, versus being swept away."

Late that night, West ordered three floodgates opened at Tom Miller Dam. The gates remained open until early the next morning.

1981_flood_austin_shoal_creek_w00720.pngKey lessons for public: Be realistic; be prepared; "Turn Around, Don't Drown"

While the flood was essentially beyond LCRA's control, the agency has used it, and subsequent situations, to hone its flood-management operations. LCRA has upgraded its chain of dams to ensure they can withstand catastrophic flooding and respond quickly to emergency operations. It has also developed closer working relationships with Austin for better coordination of operations between the Highland Lakes chain and Longhorn Dam during floods.

LCRA also has worked to inform and educate the public about severe weather and flood conditions and the responsibility of basin residents to protect themselves from flood dangers. Nowadays, most folks can monitor local weather conditions broadcast by NOAA Weather Radio Al​l Hazards, thanks to transmitters erected by LCRA that blanket the lower Colorado River basin.

Folks also can check LCRA's website for updated river and lake conditions​, as well as real-time conditions from LCRA's Hydromet network of electronic weather and streamflow gauges. If they live along any of the Highland Lakes, they can even sign up for a special LCRA service that notifies them if floodgate operations are imminent.

Even so, the Memorial Day Flood offers three lessons for the public in protecting themselves from future events, according to LCRA General Manager Tom Mason.

"The first lesson is that floods can occur at any time, even during periods of extreme drought such as what we are currently experiencing," Mason noted. "They also can occur with little or no warning, so we should never be lulled into a sense that they won't happen.

"Second – while LCRA's dams have prevented many floods or lessened their impact, there are limits to what we can do to prevent floods, especially if they occur downstream of Mansfield Dam," he continued. "Be alert to severe weather and flood conditions, whenever and wherever they occur.

"Finally, the fact that almost half of the flood's fatalities occurred at or near low-water crossings points to the need to obey the slogan, 'Turn Around, Don't Drown,'" Mason said. "You should never attempt to drive through any flooded roadway."

Additional information about the Memorial Day Flood

John Williams, a senior communications specialist at LCRA, lived near a neighborhood that was devastated by the Memorial Day Flood and recalls that it looked like "a war zone."