Document / Publication

  • Do more with your content!Discover PreventionWeb Services
  • 2019 state of U.S. high tide flooding with a 2020 outlook

    Email sent!

    An email has been sent to the email addresses provided, with a link to this content.

    Thank you for sharing!


2019 state of U.S. high tide flooding with a 2020 outlook

Source(s):  National Oceanic and Atmospheric Administration (NOAA)

Sea level rise flooding of U.S. coastlines is happening now, and it is becoming more frequent each year. 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 report argues that 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. Observations from NOAA’s national tide gauge network calibrated to the national set of coastal flood thresholds used by local emergency managers are tracking this phenomenon. NOAA’s National Ocean Service calls such flooding high tide flooding (HTF), and its cumulative toll is damaging to subsurface and ground-level infrastructure and is disrupting lives and livelihoods.

This publication reports that in 2019 (May 2019–April 2020), the national (outside of Alaska) median HTF frequency of 4 days tied its second-highest value, and its decadal trend continues to accelerate. The U.S. annual HTF frequency now is more than twice that in the year 2000 due to rising relative sea levels (RSL), which in 2019 rose to a record-setting 0.34 m (1.1 ft) nationally relative to1920 levels. Next year (May 2020–April 2021), acceleration in HTF and its impacts are expected to continue under near-neutral conditions of the El Niño Southern Oscillation. Under current floodplain management practices, by 2030 the national HTF frequency trend is likely to further increase by about 2–3 fold (national median of 7–15 days). In 30 years (by 2050), it is likely to be 5–15 fold higher (national median of 25–75 days), which could, in some places, imply HTF flooding would become the new high tide (~180 days/year).

Add this content to your collection!

Enter an existing tag to add this content to one or more of your current collections. To start a new collection, enter a new tag below.

See My collections to name and share your collection
Back to search results to find more content to tag

Log in to add your tags
  • 2019 state of U.S. high tide flooding with a 2020 outlook
  • Publication date 2020
  • Author(s) Sweet, William; Dusek, Gregory; Carbin, Greg et al.
  • Number of pages 17 p.

Please note:Content is displayed as last posted by a PreventionWeb community member or editor. The views expressed therein are not necessarily those of UNDRR PreventionWeb, or its sponsors. See our terms of use