New federal report: NC coast to see big surge in flooding as sea levels rise

Published July 16, 2020

By Rob Schofield

A team of scientists at the National Oceanic and Atmospheric Administration has released a new study entitled “2019 State of U.S. High Tide Flooding with a 2020 Outlook” and, as you probably could have guessed, the news isn’t great. The report predicts continued increases in flooding along the North Carolina coast as sea levels rise and offers some specific predictions for four communities: Duck, Oregon Inlet, Beaufort and Wilmington.

This is from the executive summary:

“Sea level rise flooding of U.S. coastlines is happening now, and it is becoming more frequent each year. This flooding typically occurs when ocean waters reach 0.5 meter (m) to 0.65 m above the daily average high tide and starts spilling onto streets or bubbling up from storm drains. Evidence of a rapid increase in sea level rise related flooding started to emerge about two decades ago, and it is now very clear. This type of coastal flooding will continue to grow in extent, frequency, and depth as sea levels continue to rise over the coming years and decades.”
After explaining that there are more coastal flood warnings taking place – often with no storm in sight – the report puts it this way:

“This will become the new normal unless coastal flood mitigation strategies are implemented or enhanced. Communities are investing in coastal infrastructure upgrades and adaptation strategies to address current flooding issues, but concerns regarding property access and future valuation/exposure, business disruption, public health, and other such concerns are growing.”
The report notes that the overall frequency of high tide flooding is likely to increase by “2-3 fold” by 2030 and “5-15 fold” by 2050 (a situation that would effectively make flooding the default situation in many communities).

Readers can check out Appendix 1 of the document for specific community predictions, but the numbers for North Carolina are sobering. It predicts that Duck will see 6 to 11 high tide flooding (HTF) events this year. In the year 2030, it puts the likely number of such events at 20 to 30 and by 2050, 55 to 135.

For Oregon Inlet the numbers of HTF events are:  2020 – 4 to 7; 2030 – 7 to 15; 2050 – 35 to 165.

For Beaufort: 2020 – 1 to 3; 2030 – 6 to 15; 2050 – 25 to 100

For Wilmington: 2020 – 2 to 5; 2030 – 4 to 9; 2050 – 15 to 65.