Hans W. Paerl, Nathan S. Hall, Alexandria G. Hounshell, Richard A. Luettich, Karen L. Rossignol, Christopher L. Osburn, Jerad Bales

Scientific Reports

Published date July 23, 2019

Recent increase in catastrophic tropical cyclone flooding in coastal North Carolina, USA: Long-term observations suggest a regime shift

  • Finds a period of unprecedentedly high precipitation since the late-1990’s, and a trend toward increasingly high precipitation associated with tropical cyclones over the last 120 years consistent with observations elsewhere and with predicted changes in a warming climate
  • States that, since the late-1990’s, coastal North Carolina (NC) has been impacted by 36 tropical cyclones, with three recent storms resulting in 2-percent or less annual exceedance levels flood events in the NC coastal plain
  • Examines continuous rainfall records for coastal NC since 1898, and takes a closer look at the apparent increased frequency and magnitudes of extreme tropical cyclone-driven flood events since 1999 in North Carolina
  • Questions whether the apparent increased frequency and magnitudes of such events is just coincidence or whether there is a regime shift in tropical cyclone flooding and associated ecosystem impacts
  • Looks at three extreme floods resulting from high rainfall tropical cyclone events in the past 20 years:
    • At Kinston, NC, Hurricane Floyd (1999) was rated a 2-percent exceedance level flood
    • The most recent Hurricane Florence (2018) also resulted in a 2-percent annual exceedance level year flood
    • Peak flow following Hurricane Matthew (2016) resulted in a 0.8-percent annual exceedance level flood in Kinston, NC
  • Finds that these three rainfall events are a consequence of the increased moisture carrying capacity of tropical cyclones due to the warming climate
  • States that the observations are consistent with similar observations elsewhere and with predicted hydrologic, nutrient and carbon flux changes taking place in a warming climate
  • The authors state they do not offer a full attribution analysis, which may be conducted in a variety of ways including numerical modeling that replicates the events our observations are consistent with observations elsewhere and with predicted changes in a warming climate
  • Concludes that rather than attributing a particular event to global warming, we should consider whether a warming climate made these events more likely, which our records suggest is the case for coastal NC