“It is not unheard of for a storm to form in December, but it is far from ordinary,” wrote Frank Strait in the South Carolina Department of Natural Resources (SCDNR) weather alert newsletter for Nov. 30. Strait is the severe weather liaison for the agency. “There have been a total of 16 named December storms in the Atlantic’s historical record, second-most of the off-season months, behind May. One storm impacted South Carolina back in early December 1925. So, while it’s unlikely that we will see any more storms until at least late May, it’s something we have to watch.”
The hurricane season traditionally runs from June 1 to Nov. 30. However, Strait said that there has been discussion of moving the start date up to May 15 due to the number of storms occurring in May in recent years.
“It seems in the last decade we have been getting impact from more May storms for South Carolina,” added Cary Mock, professor with the University of South Carolina Department of Geography. “(We’re) not sure if that is due to human-induced climate change or not, but it clearly shows up in the observational record. These are tropical storms, not hurricane intensity.”
There are three types of tropical cyclones that are differentiated by their level of intensity. Tropical depressions are the weakest, followed by tropical storms. Hurricanes are the most intense form of tropical cyclone. The World Meteorological Organization assigns names to tropical storms and hurricanes, while tropical depressions are assigned an identification number.
“In terms of number storms, it was a very active season,” Strait said. “We had 21 named storms. The average is 14. It was a pretty active season. It wasn’t as active as last year. We had 30 last year, which is the record.”
According to Strait, six tropical cyclones impacted South Carolina residents this year. Of particular note in the Lowcountry were Tropical Storm Danny that brought over 6 inches of rain to Bluffton on June 28; Tropical Storm Fred, which delivered 3 to 6 inches of rain across the Southern coastal region Aug. 17; and Tropical Storm Mindy pounded the Lowcountry with another 6 inches of rain Sept. 9.
One factor driving the high number of storms over the past two seasons has been the presence of La Niña conditions. During La Niña, cooling waters in the Pacific leads to increased hurricane activity in the Atlantic basin. These conditions were present during the record number of tropical cyclones in 2020, and they are expected to continue into the coming year.
La Niña not only influences the number of hurricanes in the area, but it also leads to drier winter conditions in the region.
Only 10 days after the end of the hurricane season, state officials declared incipient drought conditions – the lowest level of drought – in 34 of the state’s 46 counties. Beaufort, Charleston and Jasper counties are among the 12 counties with normal conditions according to the SCDNR.
However, the U.S. Drought Monitor, a research organization that watches drought conditions across the nation, reported recently that at least a portion of every county in the state is experiencing either abnormally dry or moderate drought conditions.
“We are currently in a La Niña winter, which tends to provide winter conditions that are warmer and drier than normal for the Southeast United States,” said Elliot Wickham, SCDNR climatologist. “Unfortunately, most of the state started out dry as we entered the La Niña, which increases the potential that the drought will intensify. Winter rainfall is important for recharging our surface and groundwater resources when evaporation and demand are low.”
Wickham added that an active hurricane season doesn’t necessarily negate the potential for drought.
“An active season means that many tropical systems may form, but an active season status does not predict how many storms will reach North America, nor how many will impact each state,” Wickham said. “So even if we have an active season, some of those storms may loop back into the Atlantic and never hit land. Or, they may hit another part of North America and not affect us in South Carolina.”
The impact of climate change is another factor influencing this seemingly mixed bag of Lowcountry weather. According to the National Oceanic and Atmospheric Administration (NOAA), its scientists and partner scientists found that climate change is likely fueling more powerful hurricanes, while flooding during hurricanes is being amplified by sea level rise. While the intensity of tropical cyclones is expected to increase, some models predict that the number of storms per season will decrease.
Researchers have also found that the speed of tropical cyclones might have slowed, leading to more local flooding as storms linger over impacted areas. There is some evidence that the change in speed observed is the result of more accurate tracking available as a result of improved technology, and further research is required before the matter can be definitively decided.
“The point that we want to make above all others is that, no matter what might happen each season, we strongly urge all South Carolinians as well as residents of any other area with risk to tropical cyclones, to be diligent in preparedness efforts,” SCDNR’s Strait said. “No matter whether we have a season with 25 named storms or an unusually quiet one with just a few, one of those storms might well be a major hurricane headed toward you. Being prepared in advance makes dealing with a hurricane much easier when the threat is realized and a major hurricane is clearly on the way.”
For more information on hurricane preparedness, visit hurricane.sc.
Tony Kukulich, a recent transplant to Bluffton, is an experienced freelance news writer and photographer.