Written by: Daniela Miranda
While hurricanes are often feared for their intensity and devastation, storm surge, rather than the storm itself, “is often the greatest threat to life and property from a hurricane.” Today, we explore the science behind storm surge, its potential impact, and ways to mitigate it.
Tropical storm winds push water toward the shore producing storm surge - the abnormal rise of water generated by a storm. Storm tides differ from storm surge in that they account for water rise from both astronomical tides and storm surge (see Figure 1). Tides, waves, and freshwater input all contribute to rising sea levels.
Figure 1: Storm Surge vs. Storm Surge
The Saffir-Simpson hurricane wind scale does not take into account storm surge nor does it dictate the severity of storm surge. In 2005, Hurricane Katrina, a category three hurricane, accumulated $75 billion worth of damage. Similarly, in 2008, Hurricane Ike, a category two hurricane, caused $24.9 billion worth of damage. Katrina had a storm surge twenty-eight feet above normal levels while Ike had a surge of fifteen to twenty feet above sea level.
Over half of the United States’ economic productivity is located within coastal areas and many coastlines lay less than ten feet above sea level. Storm surge has the potential to severely damage infrastructure and disrupt the lives of thousands. Because water weighs approximately 1700 pounds per cubic yard, it can quickly erode beaches and damage coastal highways before moving towards residential areas. Damage to critical infrastructure, such as electricity and water sources, threatens public health, the environment, and the economy. Storm surge leaves areas close to sea level vulnerable and rising sea levels only exacerbate storm surge related-problems.
Storm surges move and flood areas quickly, making it difficult to predict storm stages. They can occur before, during and after the center of the storm passes. Storm surge creates many hazards including: impassable roads, water and sewage problems, power outages, down power lines and risk of electrocution.
To mitigate risks and protect against flooding from storm surges, communities build levees and storm barriers and gates. After the levees collapsed during Hurricane Katrina, experts realized that floodwalls and levees are unsustainable. Unfortunately, no single piece of infrastructure will do the job. Instead, we need a coordinated system of protective infrastructure and disaster management strategies.
Comment below your thoughts on tropical storms and storm surges!