Last week, NOAA released its “2024-25 Annual High Tide Flooding Outlook” report. NOAA researchers predict fewer high-tide flood days than last year. The outlook details high-tide flooding events from May 2023 to April 2024 at 97 NOAA tide gauges along the U.S. coast. It also provides a flooding outlook for these locations through April 2025 accompanied by decadal projections and sea level rise scenarios out to 2050.
As sea level rise continues, it no longer takes severe weather to cause flooding along the coast, according to FEMA. This flooding is increasingly disrupting life in America’s coastal communities, which are home to almost 40% of the U.S. population. FEMA notes that high tide flooding, sometimes referred to as “nuisance” or “sunny day flooding,” is increasingly common due to long-term sea level rise, driven in part by climate change. It occurs when tides reach 1 to 2 feet above the daily average high tide, depending on location. Notably, due to long-term sea level rise, the U.S. now experiences an additional five median flood days per year compared to 2000 — a roughly 200% increase.
The outlook predicts that from May 2024 to April 2025 the U.S. will experience a median range of 4 to 8 high-tide flood days, slightly fewer than last year’s predicted 4 to 9 days, as El Nino conditions transition into La Nina. Areas along the western Gulf Coast and Pacific Islands are projected to experience the most high-tide flood days, ranging between 5 to 16 days and 7 to 15 days, across the respective regions. The Atlantic and Gulf coasts are expected to receive significant funding, since NOAA has predicted an above-normal 2024 Atlantic hurricane season. The report also provides a summary of high tide flooding in 2023. “NOAA’s high tide flooding outlook is critical to the nation’s communities as they build their climate resilience,” said Jainey Bavishi, assistant secretary for oceans and atmosphere and NOAA deputy administrator. “The increase in high-tide flooding has affected infrastructure in coastal communities across America, especially in underserved communities.” Read the full report at NOAA.
- For more information on hazard mitigation related to sea level rise and high tide flooding, visit this Climate Resilience Toolkit page.
- And for more information on sea level rise at a community level, visit this NOAA Sea Level Rise Viewer tool page.
WaterISAC also encourages members to review the EPA resource, "Flood Resilience: A Basic Guide for Water and Wastewater Utilities," which is an important guide to help utilities understand their flooding risk and identify practical mitigation options to protect your critical assets.
