Tornado threat from landfalling hurricanes

 

Ida's September 2021 severe weather in the Mid-Atlantic Region (Source: NOAA)

In addition to storm surge-related flooding at the coast and inland flooding from heavy rainfall, hurricanes often spawn tornadoes.  Tornadoes caused by tropical systems aren’t usually very strong, but a heightened danger surrounds them because they are often obscured by heavy rain.  Some tropical systems have produced more tornadoes than others, as described below. 

2021: Hurricane Ida was a Category 4 hurricane that made landfall in Louisiana following Hurricane Laura a year earlier.  Ida was even more destructive and ranks as the sixth costliest hurricane in U.S. history with $82.4 billion in damages (2023 dollars), according to NOAA.  It spawned dozens of tornadoes from the U.S. Gulf Coast north to Pennsylvania and New Jersey.  That included an EF-2 on the Enhanced Fujita Scale in Anne Arundel County, Maryland.  It had peak winds of 125 mph and was on the ground for more than 11 miles. 

2018:  The majority of the damage caused by Hurricane Florence resulted from widespread flooding in the Carolinas and parts of Virginia.  The National Weather Service office in Wakefield, Virginia also confirmed that 10 tornadoes occurred in the Richmond, Virginia area on September 17, which were spawned by the remnants of Florence.  The strongest was an EF-2 tornado with wind speeds of 115-125 mph.  These tornadoes occurred three days after the storm initially made landfall in North Carolina.  Florence did $29.0 billion worth of damage (2023 dollars).

2004:  Hurricane Ivan was a long-lasting Cape Verde hurricane and a Category 5 storm at peak intensity with sustained winds of 165 mph.  It made landfall along the U.S. Gulf Coast on September 16 as a Category 3 hurricane.  Ivan had far-reaching impacts, including in the Mid-Atlantic region where its remnants sparked a tornado outbreak on September 17, 2004.  According to NOAA, Ivan was the top tornado-producing hurricane on record with a total of 127 tornadoes in the United States.  It also did $33.0 billion worth of damage (2023).

2004:  Hurricane Frances made landfall on Florida’s East Coast as a Category 2 hurricane less than two weeks before Ivan’s landfall.  Like Ivan, Frances created a large and far-reaching tornado outbreak over several days.  Over 100 tornadoes were spawned by Frances and its remnants between September 4 and September 8.  Of these, roughly two dozen occurred in the Mid-Atlantic region.  Hurricane Frances remains in third place for the total number of U.S. tornadoes it caused (103).  Frances also did $15.8 billion worth of damage (2023).