CHARLESTON, S.C. (WCBD) – As Tropical Storm Elsa makes its way through South Carolina, several areas are under a tornado watch sparked by the storm’s high winds and heavy rotation.
Hurricanes, in general, are “big wind machines,” according to Storm Team 2’s Chief Meteorologist, Rob Fowler. With winds coming from all different directions, hurricanes can produce “spin-ups,” resulting in tornadoes.
As tropical systems move over land, the likelihood for tornadoes increases, in part due to the friction created between lower-level winds and obstacles such as buildings and trees. Fowler explained that the low-level winds slow down, but higher-level winds continue moving at high speeds, creating what is known as vertical shear.
According to the National Oceanic and Atmospheric Administration (NOAA), vertical shear is one of the main factors in producing tornadic activity.
Tropical systems that originate from the Gulf travel over more land than those that originate in the Atlantic and ‘graze’ the coast. Although “almost all tropical cyclones making landfall in the United States spawn at least one tornado,” NOAA confirms that “Gulf coast landfalling [tropical systems] are more likely to produce tornadoes.”