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Recent tropical storm damage in South Carolina, has been labeled by the media as a 1000 year flood. That is totally bogus.  While the flood damage was devastating, it was not a once in 1000 year event.  Similar catastrophic weather events are becoming common all across the US, and the southeast is no exception.  In 1989, hurricane Hugo made landfall in Charleston, South Carolina, with devastating effect.

I lived in Charleston at the time. Fortunately, I had the common sense to evacuate the morning before Hugo made landfall. It was a major problem coming back a week later, almost impossible to find my apartment, which was relatively undamaged. There were no street signs, and all my navigation landmarks were gone. While it’s true that a hurricane is not the same as a flood, if you happen to live at ground zero, the difference is not all that meaningful.

Charlotte, North Carolina, where I live now, was also on Hugo’s path, but 200 miles inland. Even so, Charlotte also suffered major damage. Some areas were without power for weeks. That was partly because damage repair efforts were focused on the even more heavily damaged areas further south, along Hugo’s path.

Most of the damage from Hugo was the result of high winds, while the recent damage to South Carolina was from heavy precipitation. Hurricane Joaquin was only a minor player, it was more than 300 miles off the coast at its closest approach. But it stirred up a lot of moisture, and a stalled low pressure system over Florida picked up a good portion of that moisture, and deposited it squarely on South Carolina. Tropical systems like these occur every year in the southeast and along the gulf coast.  Most don’t deposit such huge amounts of moisture, but they are not extremely rare events either.

My contention is that when you look at history, severe flooding happens relatively frequently. Add the potential of wind and storm surge from hurricanes, it starts to look like a person living near the coast could expect A catastrophic weather event twice in their lifetime. In Charleston, the interval between Hugo and the recent floods is 26 years. We know that climate change is causing extreme weather events to occur more frequently. Maybe once or twice in a lifetime will be an underestimate. Does the historical record confirm the idea that these events happen frequently?

  • The Pacolet Flood of 1903. Pacolet river is a tributary of the Broad river. It runs just east of Spartanburg, SC. The town of the same name is a few miles southeast of Spartanburg. The death toll was between 65 and 80 people, a record for the state. There are many accounts of textile, corn and flour mills being swept away, along with railway bridges. The Southern Railway bridge, near Clifton, South Carolina, which was built on 45 foot tall granite piers was completely destroyed.
  • The Great Flood of 1908 primarily affected South Carolina. There was flooding reported in 80% of the state. Virtually every major river rose above flood levels, some were 22 feet above flood stage. During this event most of the rain fell in a single 16 hour period. Many railroad bridges and roads were destroyed, along with power plants. One eyewitness account claimed that most of the city of Spartanburg was under water at the storm’s peak.
  • The Great Catawba Flood of 1916 was the result of two hurricanes, converging over the western Carolinas and northern Georgia. Reduced to tropical storms, they still deposited massive amount of rain. The French Broad River was 17 feet above flood level, the Catawba reached more than 20 feet about the previous record. More than 22 inches of rain were recorded in a single 24 hour period.
  • The 1928 Okeechobee hurricane. By the time it reached the Carolinas it was a tropical storm which produced 4 to 9 inches of rain, not unusual for a slow moving tropical storm. Heavy rains earlier in the month had saturated the soil. The land and drainage system couldn’t absorb more.
  • The 1940 Flood. Another tropical system that deposited its moisture in western and northern North Carolina. The high water marks at several river gauges have never been exceeded.
  • The Homestead Hurricane of 1945. This was a category 4 hurricane when it made landfall in Florida. As in the 1940 flood the damage was made worse because heavy rains 4 weeks earlier had saturated the ground. The river gauge in Fayetteville reached 30 feet above flood level. Because the flood peaks didn’t occur until a few days after the storm, loss of life was relatively small. Property damage was extensive.
  • Tropical Depression Klaus and Tropical Storm Marco in 1990. These systems together set rainfall records through central South Carolina and some of the southern Piedmont of North Carolina. Double digit rainfall levels were recorded in many areas.
  • Hurricane Floyd in 1999 made landfall as a category 2 storm at Cape Fear, North Carolina. There was extensive flooding in most areas east of I-95. More than 7000 homes were completely destroyed, another 17,000 rendered uninhabitable. Several locations along the storm’s path recorded more than 20 inches of rainfall.

The Southern Railway passenger station at Asheville

The Great Catawba Flood – 1916

That’s a long list of major, damaging weather events in the last 113 years. While the recent storms set some new rainfall records, calling it a 1000 year event doesn’t seem to be correct. Let’s also keep in mind that these are storms which caused regional flooding. Hurricane Hugo in 1989 or Hurricane Hazel, a category 4 storm that made landfall in North Carolina in 1954, are not on the list because most of the damage they caused was related to wind and storm surge.  Taken together, these are the worst of the worst in terms of damage. There are many more that only effected smaller areas.

The climate across the US is getting both warmer and wetter. The long range outlook is that the southeast will certainly be impacted by this trend It seems perfectly reasonable to assume that large numbers of people living in low lying areas will see significant events like this two or more times during their lifetime.

Every region in the US will have it’s own unique climate challenges. Every person has to make decisions about how they are going to deal with these events. Better to make adjustments before mother nature makes decisions for you.

When I relocate, my plan is to be 50′ above the nearest water source, and to build for 20 inches of rain along with significant wind. Cheaper to do that than hope the insurance company will pay off.

Disasters happen. We still have no way to eliminate earthquakes, wildfires, hurricanes, floods or droughts. We cope as best we can by fortifying ourselves against danger with building codes and levees, and by setting aside money to clean up afterwards. Seth Shostak

Links

NOAA – Historic Floods of North Carolina

NOAA – Historic Floods of South Carolina

SC Flood is 6th 1000 Year Event Since 2010

History of North Carolina Hurricanes