National Climate Report - August 2015
Recurrent Coastal Flooding

« National Climate Report - August 2015

Recurrent Coastal Flooding

This month's State of the Climate report has, as a supplement, an analysis of the state of recurrent coastal tidal flooding, sometimes called "nuisance flooding" or "clear-sky flooding". Nuisance flooding occurs when a water level measured at a NOAA water level gauge exceeds the local elevation threshold for minor impacts established locally by the local Weather Forecast Office of the National Weather Service. While nuisance flooding is rarely life-threatening, it can be costly for building owners and infrastructure in general.

The analysis brings forward several important points:

  1. The occurrence of nuisance flooding continues to increase over years and decades, as relative sea levels continue to climb. Relative sea level rise is driven by long-term rise in mean sea level, which is strongly tied to climate change, and by subsidence of coastal land, which is significant at some locations.
  2. The year-to-year number of nuisance flooding events is also quite sensitive to the El-Niño/Southern Oscillation pattern. This is especially relevant given this year's significant and strengthening El Niño event.
  3. The year 2014 saw daily occurrences of nuisance flooding in the mid-Atlantic in line with the region's long-term and accelerating trends toward more nuisance flooding events. The West Coast saw coastal flooding events more in line with long-term trends. The Northeast and Gulf Coast regions saw below-trend numbers of nuisance flooding events.
  4. The projected totals for nuisance flooding events in 2015 indicate the potential for a record number of nuisance flooding events at several locations in the mid-Atlantic coast.

The complete report can be found here.

Citing This Report

NOAA National Centers for Environmental Information, State of the Climate: National Climate Report for August 2015, published online September 2015, retrieved on August 22, 2019 from