2016 Hurricane Season

Hugo making landfall in South Carolina

The tropical Atlantic is often most active in late September.  This season has already had 12 tropical storms, 4 hurricanes and 1 major hurricane.  That’s near the seasonal average but below NOAA’s forecast for 12 – 17 tropical storms, 5 – 8 hurricanes and 2 – 4 major hurricanes.  The 12^th named storm of 2016, Tropical Storm Lisa, was named yesterday but isn’t expected to become a hurricane or impact the United States.

The last three hurricane seasons have been quieter than average in the tropical Atlantic.  That’s not to say there haven’t been significant storms such as Hurricane Gonzalo in 2014 and Hurricane Joaquin last year.  However, as a whole, the last three seasons have featured the least amount of tropical activity in the Atlantic Ocean since the early 1990s.  That’s before the uptick in tropical activity that began in 1995.  (I recently wrote a column about the 20 year average of 15.4 tropical storms, 7.4 hurricanes and 3.5 major hurricanes through 2015.)

Although the final three years skew the numbers downward slightly, the casual observer may not realize how active the period from 1995 – 2015 was in the tropical Atlantic unless you look at the previous 20-year period.  From 1974 through 1994, there was an average of only 9.7 tropical storms, 5.3 hurricanes and 1.7 major hurricanes each year in the Atlantic Ocean.  A “major” hurricane is defined as a Category 3 or higher on the Saffir-Simpson Scale.  There was a major episode of El Nino in 1982-1983 that helped reduce the number of Atlantic tropical storms.

Hurricane experts point to the “Atlantic Multi-decadal Oscillation (AMO),” which is a natural decades-long cycle of changes in sea surface temperatures of the North Atlantic Ocean than can influence the multi-year cycles of above and below average activity in the tropical Atlantic.  The quieter-than-average period that occurred in the tropical Atlantic during the 1970s and 1980s coincided with large-scale development in Florida and other coastal areas. 

This period of below average tropical activity contributed to a period of complacency and lax enforcement of building codes.  So, when a devastating hurricane like Andrew came along in 1992, catastrophic damage occurred in south Florida.  Despite the quieter-than-average period from 1974 – 1994, Andrew was one of a handful of damaging U.S. hurricanes to occur along with Hurricane Frederic in 1979, Hurricane Allen in 1980 and Hurricane Hugo in 1989.

By coincidence, tonight is the 27^th anniversary of Hurricane Hugo’s landfall in South Carolina, which remains one of the most destructive hurricanes in U.S. history.  While the last few hurricane seasons have been more like the quieter seasons so common from the 1970s to the early 1990s, they also showed us that a damaging or deadly hurricane can occur even during an otherwise quiet season.  Although Hermine became the first hurricane to make landfall in Florida in more than a decade earlier this month, no major hurricane has impacted the United States since 2005.  So it’s important not to let your guard down during a quieter-than-average hurricane season.