One example of a successful mitigation measure saved 150 lives at the Parsons Manufacturing Plant in Roanoke, Illinois on July 13, 2004.  Parsons is a custom manufacturing company that produces parts for other businesses such as Caterpillar and John Deere.  The plant’s owner, Bob Parsons, had built three reinforced tornado shelters in his building when he designed the facility thirty-five years prior.  The factory’s restrooms doubled as tornado shelters and were built with sturdy concrete and steel-reinforced walls plus thick concrete ceilings (Floreancig).  Parsons also implemented a severe weather action plan that included monitoring NOAA weather radio and activating plant spotters, and the facility staff practiced regular tornado drills.

The mitigation measures that Bob Parsons took were rooted in personal experience.  When he first started his business in the early 1970s, he operated out of an existing building near the current location in rural Illinois.  In 1972, a tornado struck the cornfield across the road from his building.  He remembered feeling helpless because “a tornado passed right by us and we had no place to go” (Parsons).  A few years later, when he needed to build a new facility to expand his business, he chose to build across the road in that same cornfield and made sure to include a storm shelter.  From that point forward, whenever Parsons added another building, he always included a storm shelter.

Although thirty-five years passed before Bob Parsons witnessed the successful results of his mitigation measures, his foresight became evident on the afternoon of July 13, 2004.  That afternoon an F-4 tornado completely destroyed his entire facility, with the exception of the storm shelters.  When a severe thunderstorm watch was issued that afternoon, plant leadership began actively monitoring NOAA weather radio and alerted trained employee spotters.  Around 2:30pm, these employees saw a large tornado about two miles to the west that was headed right for the plant.  They promptly alerted all of the workers and visitors present to take cover immediately in the storm shelters.  Within minutes, the tornado ripped apart the entire 225,000 square foot facility, twisting steel support beams and depositing employees’ cars inside the factory.  Despite this destruction, all 150 people present at the time of the storm survived.  According to the National Weather Service, the number killed could have been as high as seventy percent if the company did not have the reinforced storm shelters (Ridgeway).

This mitigation measure was successful because the business owner recognized the existence of tornadoes as a hazard in his area and took action.  In order to mitigate a hazard, the person responsible must first recognize the hazard and understand the associated risk, and Bob Parsons recognized that tornadoes were a real hazard in Illinois.  He learned from his previous tornado experience when he had no place to take shelter, and he actually spent money to invest in practical measures to minimize the human loss of life should a tornado happen again.  Although the building of storm shelters was a monetary investment, Parsons used a necessary component of the facility – restrooms – to serve a dual purpose and provide shelter during storms.

Another reason his mitigation efforts were successful was that he combined a physical shelter with a formal disaster plan for his facility.  The storm shelters would have been of no use if plant leadership did not have a plan to monitor weather conditions and warn employees or if the employees had not practiced taking shelter during drills.  Since employees activated and practiced their disaster plan, all personnel made it to the storm shelters three to five minutes before the tornado struck (Slattery).  Other businesses such as Green Country Energy in Jenks, Oklahoma have even modeled their storm shelters after the success of the Parsons story (Author Unknown).

In contrast to the success of the mitigation effort at the Parsons Manufacturing Plant, an unsuccessful mitigation attempt at the Wivenhoe Dam contributed to the severity of the January 2011 floods in Australia.  In 1974, the city of Brisbane experienced its worst disaster at that point in its history.  A devastating flood killed fourteen people and damaged 6,700 homes (Fickling).  To minimize losses of property and human life in future disasters, the Wivenhoe Dam was constructed.  During non-flood events, the dam also provides drinking water storage for the city of Brisbane.  The dam, which was completed in 1984, is located about fifty miles upstream from Brisbane.  Although Brisbane experienced some flooding in the years following the dam’s construction, none of the floods were as severe as the 1974 floods.  The extended drought conditions caused by El Nino in the last decade resulted in low water levels in the river and dam storage compartment.  Thus, the Wivenhoe Dam was not severely tested until the period between October 2010 and January 2011 (Fickling).

After a period of extremely heavy rain, dam engineers were finally forced to open flood gates at the dam to allow water to drain into the river in January 2011.  Wivenhoe was designed as an earth and rock fill dam and cannot withstand overtopping.  As a result, dam engineers must open and close a series of five gates to control the flow of water from the storage compartment into the Brisbane River.  This controlled release of water prevents overtopping and avoids the release of too much water too fast, which would have serious consequences for residents living downstream (Anderson).  However, the agency that manages the dam, SeqWater, waited too long to release significant amounts of water during the January 2011 flood event.  According to experts who studied the dam during and after the flood, most of the 17,000 homes would not have been flooded if extra storage capacity had been made available by the timely release of the excess water (Thomas).

This mitigation measure was unsuccessful because the effort was subject to human error on multiple levels.  First, weather forecasters grossly underestimated the rainfall potential in the days leading up to the flood, and the policies governing water release were subject to the rainfall forecast.  A spokesperson for SeqWater stated that six out of eight forecasts between January 6 and January 9 underestimated rainfall (Marszalek).  Secondly, human error and confusion on the part of the dam operators also contributed to the poor mitigation attempt.  The engineers responsible for controlling the floodgates utilize a policy manual that governs their actions in different situations.  During the Australian government’s investigation into the disaster, one of the dam operators testified that he and his co-workers were unsure which protocol to use in the days leading up to the massive flood.  This lack of clarity constituted a breach of Wivenhoe Dam’s operating manual (Owens).  Although an ongoing investigation cleared the workers of any official wrongdoing, this mitigation measure was heavily dependent on a human making the right decision, which is always subject to error.

Lastly, in the months following the massive flood, experts have questioned the wisdom of the original decision to build a dam that stores such a large amount of water upstream from a major city like Brisbane.  A recently released study by the U.S. Army Corps of Engineers found that a dam failure at either Wivenhoe or its sister dam, Somerset, would lead to extreme loss of life (Madigan).  The report also acknowledged that an updated risk assessment for both dams is underway.  If the lessons learned from the 2011 flood are combined with this updated risk assessment, the effectiveness of the Wivenhoe Dam can be re-evaluated as a mitigation measure.





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Author Unknown. Combined Cycle Journal. 2011. 7 October 2012. <;.

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Ridgeway, Nancy. “Bradley Hilltopics Online.” Vol 11, Issue 3 Summer 2005. Bradley University. 7 October 2012. <;.

Slattery, Patrick. “No One Injured as Tornado Levels Manufacturing Plant in Illinois.” 15 July 2004. NOAA News Online. 7 October 2012. <;.

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