El Niño Likely to Boost High Tide Flooding Along U.S. Coasts

news image
Special Stories
3 Oct 2018 11:11 AM
[Coconut Grove, Florida during a king tide in 2015. Photo by Thomas Ruppert, courtesy of Florida Sea Grant via CC license.] [NOAA by Tom Di Liberto] High-tide flooding—sometimes called nuisance flooding—washes into U.S. coastal communities every year, disrupting storm- and wastewater systems, damaging roads and infrastructure, and straining city budgets. Thanks to NOAA scientists, the seasonal risk of these events doesn’t have to come as a surprise. This year’s outlook predicts an above-average number of high-tide flooding days from May 2018-April 2019 for spots on both coasts. Overall, high tide flood frequencies are predicted to be 60% higher this year across U.S. coastlines compared to the year 2000. This interactive map shows the predicted number of high tide flooding days for almost 100 locations, represented by colored dots, along the East and West Coast of the United States, the Caribbean, and Pacific Ocean. Blue colors represent a higher number of predicted flood days while green-yellow colors represent a lesser amount. At each location, you can also click for a pop-up window that shows the range of uncertainty in the 2018 forecast, the typical number of high-tide flood days observed every year (around the year 2000), and the record number through 2017. For the Northwest Pacific and Northeast Atlantic coasts, five to six days of high-tide flooding are predicted through next spring, with locally higher amounts. For instance, Atlantic City, New Jersey has 11 days predicted, plus or minus 3 days, which is six days above normal. Boston’s forecast is for 13 days of high-tide flooding, plus or minus 3 days, where the city would more commonly have just 6 days. [Number of high-tide flood days predicted for U.S. locations for May 2018-April 2019. From NOAA] Meanwhile, locations along the southeastern Atlantic, Southwest Pacific, and Gulf Coasts are predicted to observe two to four days of flooding. Relative to other places, these numbers are small, but for many of them, the forecast for 2018 is still abnormally high. Virginia Key near Miami, for instance, is forecast to see “only” three days of high-tide flooding, but the average number is closer to 0. Three days of high-tide flooding would match the record for the site. To produce these forecasts (full report), scientists not only project the recent historical trend in high-tide flood days a short time into the future, but also take into account the state of the El Niño-Southern Oscillation, which can increases the frequency of high water levels on both coasts. (Our Nuisance Flood Q&A explains how). The forecast that a weak El Niño is likely to form during late 2018 was a large influence on the prediction of higher than normal flood days. Edited for WeatherNation by Meteorologist Mace Michaels
All Weather News
More
Rounds of Severe Storms to Impact Great Plains and Midwest Through the Weekend

Rounds of Severe Storms to Impact Great Plains and Midwest Through the Weekend

A dynamic summer weather pattern is setting t

11 Jul 2025 3:20 AM
Storms Return From the Front Range to Texas

Storms Return From the Front Range to Texas

Moisture is moving back into the Central and

11 Jul 2025 3:00 AM
Medium Range Tropics Forecast Favors Gulf, CSU Updates Seasonal Forecast

Medium Range Tropics Forecast Favors Gulf, CSU Updates Seasonal Forecast

While the Atlantic appears quiet, conditions

11 Jul 2025 2:40 AM
Severe Thunderstorms Expected Across the East Coast

Severe Thunderstorms Expected Across the East Coast

The severe weather and flood threat continues

11 Jul 2025 2:35 AM
Timeline: How Catastrophic Flooding Unfolded in Texas Hill Country

Timeline: How Catastrophic Flooding Unfolded in Texas Hill Country

TEXAS - Catastrophic flooding devastated port

10 Jul 2025 10:00 AM
Ruidoso Flash Flooding - Record Crest for the Rio Ruidoso River

Ruidoso Flash Flooding - Record Crest for the Rio Ruidoso River

A slow-moving monsoonal thunderstorm develope

10 Jul 2025 1:55 AM
Dangerous Heat Building Out West

Dangerous Heat Building Out West

WEST - Heat alerts have been issued across th

9 Jul 2025 9:00 AM