Monthly High Tide Flooding Outlook
No region currently selected. Please choose a region from the drop-down menu or select a station pin in the map.
Why Will The Tide Be Higher Than Normal?
Mean sea level is typically higher in the late spring due to changing weather patterns and increasing water temperatures.
What kind of impact might I expect along the coast?
MeanLow lying areas may flood, however high tides alone will likely not cause a significant impact on the coast in most areas unless accompanied by a storm or strong winds.
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About the Monthly Outlook
Above-normal tides can trigger high tide flooding, disrupting coastal communities. This flooding can occur on sunny days and in the absence of storms. More severe flooding may occur if high tides coincide with heavy rains, strong winds, or large waves. As sea levels continue to rise, our coastal communities will experience more frequent high tide flooding - about 45-85 days/year on average nationally by 2050. Predicting the likelihood of high tide flooding helps coastal communities plan for and mitigate impacts.
The Monthly High Tide Flooding Outlook shows when and where above-normal high tides and high tide flooding may be experienced. This model does not account for real-time weather conditions. In the event of severe weather, coastal flooding may still occur outside of dates identified in this product. To monitor water levels in real-time and track storms, visit our Coastal Inundation Dashboard.
Using This Product
To get started, select a region from the drop-down menu or click a station pin on the map to see high tide flooding information for the selected month and year. Click the region tab to learn more about regional drivers and impacts of high tide flooding or the station tab to view daily flooding likelihoods.
- Map View: Visualize where high tide flooding is predicted to occur at NOS water level stations in the selected month (default is the current month). Navigate the map by selecting a region from the drop-down menu or using the pan/zoom tools. Stations are represented by pins color-coded to show flooding likelihoods:
- White - unlikely (0-5%)
- Light red - possible (5-50%)
- Dark red - likely (50 -100%)
- Region View: Learn why tides may be higher than usual in the selected region and what coastal flooding impacts the region may experience as a result of its unique geographic characteristics.
- Station View: Use the flooding likelihood calendar to identify when high tide flooding is predicted at the selected location. This calendar is available in monthly and annual formats.
CO-OPS updates high tide flooding likelihoods on a monthly basis using methodology from Dusek et al. 2023 (GitHub Repository). These flooding likelihoods are derived from a probabilistic model that incorporates tide predictions, sea level rise trends, and seasonal changes in coastal sea level to predict the potential that a higher than normal high tide may exceed established National Ocean Service flood thresholds. During these periods, high tide flooding may occur in flood-prone areas.
- Seasonal High Tide Bulletin Archive: Summer 2016 – Spring 2023
- Guided Animation: High Tide Flooding
- NOS Ocean Fact: Perigean Spring Tides
- Video (1-minute) & NOS Ocean Fact: What is High Tide Flooding