2017 Hurricane Season Wrap

Hurricane Maria on September 19, 2017  (Source: NOAA)

The 2017 Atlantic hurricane season comes to a close this Thursday, November 30.  It has been one of the busiest and most destructive hurricane seasons on record.  A total of 17 tropical storms, of which 10 became hurricanes – including 6 major hurricanes developed in the Atlantic Ocean Basin.  That’s compared to an average of 12 tropical storms and 6 hurricanes, including 3 major ones.  A “major” hurricane is defined as a Category 3 or higher on the Saffir-Simpson scale with sustained winds of 111/+ mph.

Both NOAA and Colorado State University called for a slightly busier than average 2017 Atlantic hurricane season when it began on June 1.  That forecast in the spring and early summer took into account the possible development of an episode of El Nino.  Even a weak El Nino event contributes to less favorable conditions for tropical storms and hurricanes in the Atlantic Ocean, such as increased wind shear and cooler sea surface temperatures.  

When it became apparent that El Nino wouldn’t be a factor, both NOAA and CSU scientists revised their forecast to call for an above average season.  Tropical Storm Arlene developed in April, while June and July saw a total of three tropical storms and a fourth tropical storm, Emily, developed on July 31.  The season’s first hurricane, Franklin, developed on August 9. 

Later in August, Harvey became the season’s first major hurricane.  It became a Category 4 hurricane with sustained winds of 130 mph before making landfall in Texas.  Harvey was the first major hurricane to make landfall in the United States since Wilma in 2005.  It was also the first Category 4 hurricane to make landfall in Texas since Carla in 1961.  But that was only the beginning as Harvey turned out to be the first of three devastating U.S. hurricanes this year.

2017 was the first season in a decade (and only the sixth overall) to feature two Category 5 hurricanes: Irma and Maria.  Fortunately, Irma weakened to Category 4 intensity before making landfall in the Florida Keys.  But, still caused widespread damage across Florida and Georgia.  Maria also weakened to just under Category 5 intensity before it devastated Puerto Rico.  

The final costs of Harvey, Irma and Maria won’t be known for some time.  All three could surpass Hurricane Katrina as the costliest natural disaster in U.S. history.  Congratulations are in order for the meteorologists with the National Hurricane Center and the others in private companies who worked tirelessly to inform their local communities in harm’s way.