35th Anniversary of Hurricane Dennis


Rainfall totals resulting from Dennis 1981. David Roth (NOAA/WPC)
Rainfall totals resulting from Dennis 1981.
David Roth (NOAA/WPC)

On August 18, 1981, Tropical Storm Dennis made landfall in the Florida Keys and dumped heavy rains on south Florida.  Although a weak tropical cyclone throughout its life cycle, Dennis proved the most damaging Atlantic storm for the 1981 hurricane season.

Dennis formed from an African Easterly Wave that came off Africa on Aug. 5th.  In two days, it organized into a tropical depression and the next day intensified into a tropical storm in the eastern Atlantic.  But its deepening stopped there and by Aug. 11th it encountered increasing wind shear and began to weaken.  It was a depression as it passed over the Lesser Antilles and became an open wave in the central Caribbean.  NHC was able to track the wave as it passed over Jamaica and turned north.  It stalled south of Cuba and slowly began to reorganize.  It reached tropical storm strength by the time it drifted over Cuba.  Once it made the Straits of Florida, an eye began to form and its central pressure dropped.

The NOAA aircraft were tasked with reconnaissance flights into Dennis for its passage over the Straits.  The first and last of the four flights could not fix the storm as the center was overland, but the middle two kept Dennis under constant surveillance.

It raked the Keys with gale-force winds and inundated south Florida with tropical rains.  A peak value of 25.56″ (650 mm) was measured in Homestead, FL.  Dennis drifted up the Florida peninsula over the next two days and then skirted the coast of Georgia and the Carolinas for another day and a half.  Once it recurved out to sea it briefly gained hurricane strength before being absorbed into a front out over the Atlantic north of Bermuda.  In all Dennis caused US$17 million in damages, but no deaths were directly attributed to it.