1,000-Year Flood

We never know what Mother Nature has in store. In my last blog recapping natural disasters for the first nine months of 2015, I wrote that the US had a relatively quiet tropical storm season. A few days later, on Oct. 1, a low pressure area formed over the US southeast. At the same time, Hurricane Joaquin had quickly intensified to a Category 5 storm with wind speeds of 155 mph (260 km/h), and moved into the Caribbean. The combination proved disastrous for the state of South Carolina.

After Hurricane Joaquin produced massive flooding and structure damage in the Bahamas, it swung north, paralleling the US east coast. According to an article in the October 5th issue of The Washington Post, the non tropical low pressure system over the southeast had drawn in a deep, tropical plume of water off the warming Atlantic Ocean. At the same time, this upper-level low tapped into the moist outflow of Hurricane Joaquin. The moisture pipeline fed directly into the low pressure system, resulting in a historic rainfall event.

On Oct. 3rd alone, 11.5 inches (29cm) of rain fell on Charleston in 24 hours. A few miles northeast of Charleston, 24.23 inches (62cm) fell on Mt. Pleasant in 24 hours. According to NOAA, South Carolina’s torrential weekend of rain far surpassed a 1,000-year rainfall event. A 3-day 1,000-year, rainfall event for Charleston County would have been 17.1 inches. Starting Saturday, Oct. 3, many reporting points in the county registered more than 20 inches (51cm) of rain, far exceeding the standards for a 1,000-year storm.

The flooding that came with the storm was also unprecedented. 19 people died in the storm and flood. There were 175 rescues. 469 roads and bridges were washed out. 16 dams were breached or washed away. Preliminary estimates of property loss and infrastructure repair exceed $1 billion.

Originally thought to be heading for the US east coast, much like Superstorm Sandy, Hurricane Joaquin changed course after roaring through the Bahamas, heading north and then east. While causing havoc in the Bahamas, the storm, at the same time, took the lives of 33 crew members of the US container ship El Faro. The ship experienced engine failure before it was able to change course and avoid the hurricane. Without power, it drifted into the heaviest part of the storm, encountering towering waves and 150 mph (250km/h) winds. The US Coast Guard searched for survivors, but finally announced the ship had sunk in the storm, and all hands were lost.

Whether global warming played a role in either the hurricane or the 1,000-year rain is not known. But scientists have been saying for years that as the earth and oceans get warmer, storms will get bigger and stronger.