Annual High Tide Flooding Outlook
A map showing the number of high tide flooding days at National Water Level Observation Network stations observed or projected for the selected year. Flooding thresholds are supplied by NOAA’s Office for Coastal Management.
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National
NOAA has been issuing Annual High Tide Flooding Outlooks and Assessments for over 10 years. This year, with the forecasted return of El Niño conditions, several regions are predicted to experience record flood counts.
2026-2027 Outlook
- Over the next meteorological year, May 2026 to April 2027, NOAA water level stations across the country are predicted to experience a median of 7 to 12 high tide flood days, a new record.
- Globally, El Niño conditions are returning. This phase of the El Niño-Southern Oscillation (ENSO) cycle has the potential to increase high tide flooding during the Northern Hemisphere's cool season (October to April) in regions sensitive to fluctuations in global oceanic and atmospheric cycles. Some regions are more susceptible to the influence of El Niño conditions. The Pacific Coast and the Mid-Atlantic are predicted to experience more high tide flooding as a result of these conditions. Overall, annual increases in flooding remain driven by long-term sea level change.
- NOAA predicts a below-normal Atlantic hurricane season. Though it's only one factor, El Niño conditions can suppress Atlantic Ocean hurricane development, meaning stations in hurricane-prone areas may have less than average extreme weather-related flooding this season.
- An above-average Pacific hurricane season is expected. Moderate to strong El Niño conditions are forecast to persist throughout the season, with the tropical Pacific most likely to experience a moderate or stronger El Niño. Strong El Niño conditions are typically associated with increased storm activity in the central Pacific and have the potential to add to the impacts of routine high tide flooding.
- The Northeast, Mid-Atlantic, and Pacific regions are predicted to experience similar amounts of flooding as was observed during the previous El Nino event in 2023, a record-setting year for many stations. Please refer to the Regional Summaries for more detail.
- Overall, the U.S. is predicted to experience a median of 7 more high tide flood days per year since the year 2000, a more than a 250% increase.
- As sea levels rise, coastal communities will experience more frequent high tide flooding. NOAA projects a national average of 55 to 85 days per year by 2050.
2025-2026 Review
- El Niño-Southern Oscillation (ENSO) conditions were closer to neutral during the last Outlook season, meaning global oceanic and atmospheric patterns were closer to their long-term baselines, limiting ENSO-related influences on high tide flooding.
- Overall, the U.S. Pacific Coast experienced elevated sea surface heights due to warmer than average water temperatures. These conditions, combined with the effects of long-term sea level rise, may have contributed to increased observed flooding during the 2025-26 Outlook season.
- Across all stations, 42% observed flooding within the predicted range, 36.5% below, and 21.5% above. The Mid-Atlantic and Pacific Northwest observed flood counts closest to their predicted ranges.
- Apra Harbor, Guam, set a new station record of 77 flood days, significantly above the predicted range of 4-11 days. This dramatic increase in observed flooding can be partially related to elevated sea levels, increased sea surface temperatures, and extreme weather.
- 8 stations met or exceeded previous flood day records, with 5 stations along the southern Pacific coast reaching their previous records. More details are provided in each region's summary.
National Flood Drivers
- El Niño conditions are returning. This phase of the El Niño-Southern Oscillation (ENSO) cycle weakens or reverses Pacific trade winds, allowing warm surface waters to spread eastward. This shift also moves atmospheric convection centers eastward, changing atmospheric circulation and storm patterns worldwide. El Niño driven atmospheric changes often increase the frequency of storms and onshore winds along the Mid-Atlantic Coast and suppress Atlantic hurricane activity.
- In addition to El Niño conditions, increases in high tide flooding are driven by ongoing regional factors like land subsidence, and global factors like global long-term sea level rise. These factors contribute to the potential for more severe storms, higher mean sea levels, and more frequent instances of moderate and major high tide flooding that can disrupt business, threaten homes, and damage infrastructure.
- Coastal flooding is often the result of combined effects from waves, and weather-driven events. This is known as compound flooding, that adds to the impacts of routine high tide flooding.
Note: Flood counts provided here are based on the exceedance of specific water level thresholds outlined in Patterns and Projections of High Tide Flooding along the U.S. Coastline.
Northeast
2026-2027 Outlook
This year, the Northeast is predicted to experience 5 to 11 high tide flood days.
- NOAA predicts a below-normal 2026 Atlantic hurricane season. Based on predictions, hurricanes are expected to impact routine high tide flooding; however, weather events like nor'easters (cool-season extratropical cyclones) frequently contribute to regional flooding.
- Kings Point, NY, is predicted to experience the greatest number of high tide flood days, 16 to 22. Boston, MA, and Bar Harbor, ME are just below this range with 11 to 19 days, and 10 to 17 days, respectively.
- Though the frequency of high tide flooding varies from year to year, the Northeast is predicted to experience a median of 5 more high tide flood days per year compared to the year 2000, more than a 150% increase.
2025-2026 Review
The Northeast experienced a median of 2 flood days during the 2025-2026 meteorological year, below the predicted range of 6 to 12 days.
- Boston, MA observed 6 flood days, the greatest number in the region, but below the predicted range of 12 to 19 days.
- The Northeast is not heavily influenced by fluctuations in the El Niño-Southern Oscillation (ENSO). The persistent regional increase in high tide flooding is largely driven by sea level rise
- No stations met or exceeded previous high tide flooding records.
- On average, this region experienced its lowest flood counts since 2013, with New Haven, CT experiencing zero flood days for the first time since 2001.
Regional Flood Characteristics
The Northeast continues to experience rapid increases in high tide flooding due to the long-term effects of sea level rise.
- Routine high tide flooding in the region is primarily caused by large tidal ranges and extratropical coastal storms, often during the winter and spring seasons
- Offshore storms typically bring strong winds from the east and northeast, piling up water over the region's wide, shallow continental shelf.
Mid-Atlantic
2025-2026 Outlook
This year, the Mid-Atlantic is predicted to experience 15 to 20 high tide flood days.
- NOAA predicts a below-normal 2026 Atlantic hurricane season, lowering the chance of hurricane-related weather conditions compounding routine high tide flooding. This does not limit the possibility of other routine and anomalous weather events contributing to flooding at the coast.
- This Mid-Atlantic is heavily influenced by fluctuations in global El Niño-Southern Oscillation (ENSO). The return of El Niño conditions brings increased onshore wind and storm frequency which has the potential to increase high tide flooding through the cool season, October to April.
- Lewisetta, VA, and Sewells Point, VA, are predicted to experience the greatest number of high tide flood days in the region, each up to 27 days.
- Though the frequency of high tide flooding varies year to year, the Mid-Atlantic is predicted to experience an average of 14 more high tide flood days per year compared to the year 2000, a more than 350% increase and over double last year's prediction.
- More than 75% of stations in the region are predicted to meet or exceed their high tide flood day records as El Niño is expected to compound the impact of sea level change
2025-2026 Review
The Mid-Atlantic experienced a median of 9 flood days over the 2025-2026 meteorological year, within the predicted range of 8 to 13 days
- WIndmill Point, VA, observed 18 flood days, the greatest number in the region and within the expected range of 13 to 21 days. Sewells Point, VA, was next next highest with 17 days, one more than its predicted range of 12-16 days.
- Ocean City Inlet, MD, experienced 8 flood days, tying the previous record of 8 days set in 2009.
- Most stations in the Mid-Atlantic observed flood counts within the expected range.
- On average this region experienced its lowest flood counts since 2022, with Atlantic City, NJ, and The Battery, NY, experiencing their lowest flood counts since 2014 and 2016 respectively.
Regional Flood Characteristics
The Mid-Atlantic continues to experience rapid increases in high tide flooding due to the long-term effects of sea level change.
- The region experiences routine high tide flooding throughout the year due to its low-lying coastal lands, and wide, shallow continental shelf, which is often exposed to storms.
- Coastal flooding in this region can also be weather driven, as tropical systems come up the coast from the south and non-tropical offshore storms bring winds and ocean currents from the east and northeast.
- The Mid-Atlantic is sensitive to fluctuations in the El Niño-Southern Oscillation (ENSO) with most stations experiencing more frequent flooding during El Niño than during La Niña or Neutral years.
Southeast
2025-2026 Outlook
- Duck, NC, is predicted to experience the greatest number of high tide flood days in the region, 22 to 27 days, followed by Wrightsville Beach, SC, and Mayport, FL, with up to 22 flood days predicted.
- NOAA predicts a below-normal 2026 Atlantic hurricane season, lowering the chance of hurricane-related conditions that compound routine high tide flooding. This does not limit the possibility of other routine and anomalous weather events contributing to flooding at the coast.
- This region is heavily influenced by fluctuations in global El Niño-Southern Oscillation (ENSO). The return of El Niño conditions increases the potential for high tide flooding through the winter.
- 50% of stations in this region are predicted to meet or exceed their high tide flood days records as El Niño is expected to compound the long-term effects of sea level change.
- Though the frequency of high tide flooding varies year to year, the Southeast is predicted to experience an average of 7 more high tide flood days per year compared to the year 2000, a more than 550% increase.
2025-2026 Review
The Southeast experienced a median of nearly 7 flood days over the 2025-2026 meteorological year, within the predicted range of 6 to 9 days.
- Duck, NC, experienced 19 flood days, the greatest in the region and more than the predicted range of 11 to 16 days.
- Most stations experienced flood counts within the expected range.
- North and South Carolina are sensitive to fluctuations in the El Niño-Southern Oscillation (ENSO), less so in Florida.
- On average, the Southeast experienced its lowest flood counts since 2022, with Charleston, SC, and Springmaid Pier, SC, experiencing their lowest flood counts since 2018 and 2019 respectively.
Regional Flood Characteristics
The Southeast Coast continues to experience increases in high tide flooding due to the long-term effects of sea level change.
- Recent, rapid changes in relative sea level are caused by global sea level change, regional oceanographic effects, and, in some low-lying areas, land subsidence.
- This region of the U.S. is largely composed of low-lying areas prone to minor flooding. Due to their low profile, coupled with land subsidence and global sea level change, these areas have observed more frequent high tide flooding events over the past few decades.
- Flooding in the Southeast can be attributed to regional sea level variability, astronomical events, and atmospheric variability, like Gulf Stream fluctuations. Atlantic hurricanes and extratropical cyclones can further compound high tide flooding impacts along the East Coast.
East Gulf Coast
2026-2027 Outlook
This year, the Eastern Gulf is predicted to experience a median of 2 to 7 flood days.
- Bay Waveland, MS, is predicted to experience the greatest number of high tide flood days, 10 to 17 days.
- NOAA predicts a below-normal 2026 Atlantic hurricane season, lowering the chance of hurricane-related conditions that can compound routine high tide flooding. This does not limit the possibility of other routine and anomalous weather events contributing to flooding at the coast.
- Overall, the Eastern Gulf is predicted to experience a median of 3 more high tide flood days per year compared to the year 2000, an almost 200% increase.
- Clearwater, FL, is the only station predicted to meet or exceed its record number of high tide flood days
2025-2026 Review
The Eastern Gulf experienced a regional median of 0 high tide flood days during the 2025-2026 meteorological year, less than the expected 3 to 7 flood days. All stations in the region observed fewer flood days than predicted.
- Bay Waveland, MS, experienced 6 flood days, the most in the region but below the predicted 11 to 18 days.
- The Eastern Gulf often experiences flooding due to extreme weather events, like hurricanes. The 2025 Atlantic Hurricane Season was less active than predicted, producing 13 named storms and 5 hurricanes, none making landfall, limiting the impacts of storm-related flooding.
- No stations in the Eastern Gulf met or exceeded previous flood records.
- On average, the Eastern Gulf experienced its lowest flood counts since 2017, with Cedar Key, FL, and Clearwater, FL, experiencing their lowest flood counts since 2009 and 2010, respectively.
Regional Flood Characteristics
This region is routinely impacted by severe weather that contributes to flooding, with extreme flooding usually caused by Atlantic hurricanes.
- Due to these severe weather impacts coupled with land subsidence and sea level change, high tide flooding in the region is becoming increasingly frequent and impactful.
- Predictions for the region vary year to year due to large-scale weather and ocean current patterns.
West Gulf Coast
2026-2027 Outlook
The Western Gulf is predicted to experience a median of 4 to 14 flood days.
- Stations in Galveston Bay, TX, are predicted to experience some of the greatest numbers in the region: Galveston Pier 21, TX, with 12 to 20 days, Morgan's Point, TX up to 18 flood days, and Eagle Point, TX, with the most, 24 to 49 days. Note: Observed flood counts at Eagle Point can be influenced by oceanic and atmospheric variables, like fresh water runoff, not monitored by NOAA water level stations.
- The Western Gulf often experiences flooding due to extreme weather events, like hurricanes. The 2025 Atlantic Hurricane Season was less active than predicted, producing 13 named storms and 5 hurricanes, though none made landfall which may have limited overall flood counts in the region.
- Though high tide flooding varies greatly from year to year, the Western Gulf is predicted to experience an average of 9 more high tide flood days per year compared to the year 2000, a more than 350% increase.
- No water level stations in the region are predicted to observe record-setting flood counts.
2025-2026 Review
The Western Gulf experienced a median of roughly 2 flood days during the 2025-2026 meteorological year, below the predicted 6 to 15 days.
- Stations in the Galveston Bay, TX area observed the most flood days in the region, with Morgans Point, TX, observing 3 days and Eagle Point, TX, 18 days.
- The Western Gulf often experiences flooding due to extreme weather events, like hurricanes. The 2025 Atlantic Hurricane Season was less active than predicted, producing 13 named storms and 5 hurricanes, none making landfall, limiting the impacts of storm-related flooding.
- Most stations in the region observed flooding below the predicted range.
- On average, the Western Gulf experienced its lowest flood counts since 2021, with Calcasieu Pass, LA, and Galveston Pier 21, TX, experiencing their lowest flood counts since 2014.
Regional Flood Characteristics
- The Western Gulf is frequently impacted by high tide flooding from the combined effects of land subsidence and ongoing sea level change. These factors contribute to extreme coastal flooding during hurricanes.
- Note: Flood counts represent the number of days where observed water levels exceed the NOS minor flood threshold. Actual impacts can vary in this region depending on local geography, infrastructure, and mitigation efforts.
Southwest
2026-2027 Outlook
The Southwest Pacific coast is predicted to experience 3 to 6 high tide flood days this year, an increase from previous years.
- This region is heavily influenced by fluctuations in the global El Niño-Southern Oscillation (ENSO). The return of El Niño conditions could increase high tide flooding through the winter.
- North Spit (Humboldt Bay), CA, is predicted to experience 17 to 23 flood days , close to its historical flood day record of 22 days. This prediction is partly due to the return of El Niño conditions, and recent increases in observed flooding.
- Though high tide flooding varies greatly each year, the Southwest is predicted to experience a median of 3 more high tide flood days per year compared to the year 2000, a nearly 250% increase.
2025-2026 Review
As a region, the southwest coast experienced a median of 7 flood days during the 2025-2026 meteorological year, above the predicted range of up to 3 days.
- El Niño- Southern Oscillation (ENSO) conditions were closer to neutral during the previous meteorological year, meaning global oceanic and atmospheric patterns were closer to their long-term baselines than expected, limiting impacts on high tide flooding.
- North Spit (Humboldt Bay), CA, observed 22 flood days, the highest in the region. San Diego, CA, and Point Reyes, CA, observed 8 flood days, followed by La Jolla, Los Angeles, Santa Monica, and Monterey, California, with 7 observed flood days.
- Pacific regions experienced elevated sea surface temperatures from June to August 2025. These above-average conditions can compound routine high tide flooding and increase the potential for extreme-weather related impacts.
- 5 stations met or exceeded their previous flood count record during the previous meteorological year. Los Angeles, CA, and North Spit, CA, both set new flood days records with 7 days and 22 days respectively.
Regional Flood Characteristics
Changing water levels along the Southwest Coast are caused by global sea level change and regional oceanographic effects.
- In general, the deep, narrow continental shelf along the Southern Pacific coast reduces the amplification of tides and storm surge. The region experiences relatively infrequent coastal storm systems, limiting the overall frequency of significant flood events; however, this region can experience damaging flood levels from high waves.
- Flooding along southwest Pacific coasts is heavily influenced by the El Niño-Southern Oscillation (ENSO). The return of El Niño conditions greatly increases the potential for high tide flooding in the region
Northwest
2026-2027 Outlook
The Pacific Northwest is predicted to experience 7 to 18 high tide flood days this year, an increase from previous years.
- This region is heavily influenced by fluctuations in global El Niño-Southern Oscillation (ENSO). The return of El Niño conditions creates the potential for increased high tide flooding through the winter
- Toke Point, WA, is predicted to experience the greatest number of flood days in the region, 17 to 29 flood days, followed by South Beach, OR, and Astoria, OR, with 16 to 24 days, and Charleston, OR, with 15 to 23 days.
- High tide flooding in the Northwest remains relatively consistent to observed values in the year 2000. This year, with the return of El Niño conditions, the Northwest is predicted to experience a median of 7 more flood days compared to the year 2000, more than a 150% increase.
- No stations in the region are predicted to observe record-setting flood counts.
2025-2026 Review
The Northwest Coast experienced a median of 8 flood days, top of the predicted range of flood days.
- El Niño- Southern Oscillation (ENSO) conditions were closer to neutral during the previous meteorological year, meaning global oceanic and atmospheric patterns were closer to their long-term baselines than expected, limiting their impacts on high tide flooding. The Pacific Northwest observed flooding near the upper end of the predicted range, indicating flooding was less ENSO-related, and partially attributed to long-term sea level rise.
- The Pacific region experienced warmer-than average water temperatures during June to August 2025. These temperatures elevated baseline water levels and increased the potential for high tide flooding when combined with tides and coastal storms.
- Toke Point, WA, observed the most flooding in the region, and has for many years.
- All but one station observed flooding within the predicted range. Port Angeles, WA, experienced 9 flood days, more than the expected range of up to 5 high tide flooding days.
- No water level stations met or exceeded previous flood count records.
Regional Flood Characteristics
Recent rises in relative sea levels are caused by vertical land movement, global sea level rise, and regional oceanographic effects.
- Flooding in the Pacific Northwest is tidally driven. The wide continental shelf creates large tidal ranges and the potential for greater flood-related impacts when compounded by weather events; however, year to year variations in high tide flood frequencies are highly associated with El Niño conditions.
- Strong winds and distant swell create large waves that contribute to flooding in the region. While these waves are not yet fully captured in NOAA's water level observations, they can overtop coastal structures.
- The Northern Pacific coast's continental shelf is deeper and narrower than that of the Southern Pacific, leaving it more exposed to winter storms that can amplify storm surge and flood low-lying areas.
Pacific Islands
Regional Analysis
The Western Pacific Islands are predicted to experience 11 to 23 high tide flood days this year.
- Kwajalein Island, Marshall Islands, and Apra Harbor, Guam are predicted to experience the greatest number of high tide flood days in the region, with 22 to 43 days, and 13-36 days, respectively.
- NOAA predicts an above-normal 2026 Central Pacific Hurricane Season, increasing the chance for compound flooding from hurricanes that adds to the impacts of routine high tide flooding. El Niño conditions are expected to persist throughout the hurricane season, with the tropical Pacific predicted to experience a moderate or stronger El Niño. Strong El Niño conditions are typically associated with dramatically elevated levels of hurricane activity in the central Pacific.
- Though high tide flooding varies greatly year to year, overall, the Pacific Islands are predicted to experience an average of 13 more high tide flood days per year compared to the year 2000, a nearly 750% increase.
2025-2026 Review
The Western Pacific Islands experienced a median of 33 flood days during the 2025-2026 meteorological year, more than the predicted range of 8 to 20 days.
- Apra Harbor, Guam, set a new station record of 77 flood days, the most in the region and well above the predicted range of 4-11 days. The dramatic increase in observed flooding can be attributed to elevated sea levels in the region.
- Pago Pago, American Samoa, and Kwajalein Island, Marshall Islands, experienced flooding within the predicted range. Apra Harbor, Guam, and Wake Island, experienced more flooding than predicted.
Regional Flood Characteristics
The Western Pacific Islands continue to experience rapid increases in high tide flooding.
- Changing relative sea levels are partly due to regional land subsidence, global sea level change, and regional oceanographic effects.
- Globally, NOAA ranks June to August of 2025 as the third warmest in its 176 year global temperature record.
- Waves, though not captured by NOAA tide gauge observations, are often a significant factor in extreme flooding, and may cause higher on-the-ground water levels than observed at tide gauges.
Note : Pacific Island flood thresholds were adjusted in 2023 to better match on-the-ground reports of flooding. Reported flood days represent the number of observed and predicted days where water levels exceed the NOS Minor flood threshold. The number of true flood days may be lower. Adjusted flood thresholds may not be representative of flooding around Kwajalein Island. Reported flood days represent the number of observed and predicted days where water levels exceed the flood threshold. The number of true flood days may be lower.
Pacific Islands
2026-2027 Outlook
The Hawaiian Islands are predicted to experience 11 to 23 high tide flood days this year.
- Kwaihae, HI, is predicted to experience the greatest number of high tide flood days in the Eastern Pacific region, 27 to 46 days, some of the highest estimates in the region. Hilo, HI, is predicted to experience the next highest number with a range of 19 to 35 days, followed by Mokuoloe, HI and Kahului, HI with up to 23 days.
- NOAA predicts an above-normal 2026 Central Pacific Hurricane Season, increasing the chance for compound flooding from hurricanes that adds to the impacts of routine high tide flooding. El Niño conditions are expected to persist throughout the hurricane season, with the tropical Pacific predicted to experience a moderate or stronger El Niño. Strong El Niño conditions are typically associated with dramatically elevated levels of hurricane activity in the central Pacific.
- Though high tide flooding varies greatly year to year, overall, the Pacific Islands are predicted to experience an average of 13 more high tide flood days per year compared to the year 2000, a nearly 750% increase.
2025-2026 Review
The Pacific Islands experienced a median of 33 flood days during the 2025-2026 meteorological year, more than the predicted range of 8 to 20 days.
- All but one water level station in Hawaii observed more flooding than predicted. Honolulu, HI observed 15 flood days, within the predicted range of 8 to 19 days. Increased flooding can potentially be attributed to greater than average sea surface heights, as well as varying regional and local flood characteristics.
- Kawaihae, HI, and Hilo, HI, both experienced 44 high tide flood days, above the regional median of 33 days.
- No stations in this region met or exceeded previous high tide flooding records over the 2025-2026 meteorological year.
Regional Flood Characteristics
The Eastern Pacific Islands continue to experience rapid increases in high tide flooding.
- Changing relative sea levels are partly due to regional land subsidence, global sea level change, and regional oceanographic effects.
- Globally, NOAA ranks June to August of 2025 as the third warmest in its 176 year global temperature record.
- Warming water contributes to higher sea levels, causing routine tides to reach further inland and produce greater impacts.
- Waves, though not captured by NOAA tide gauge observations, are often a significant factor in extreme flooding, and may cause higher on-the-ground water levels than tide gauge observations.
Note: Pacific Island flood thresholds were adjusted in 2023 to better match on-the-ground reports of flooding. Reported flood days represent the number of observed and predicted days where water levels exceed the NOS Minor flood threshold. The number of true flood days may be lower.
Alaska
Regional Analysis
NOAA collects valuable oceanographic and meteorological information from water level stations across Alaska. Based on these long-term records, several factors make predicting high tide flooding in the region challenging.
- NOAA is still working to establish consistent and representative high tide flooding thresholds throughout Alaska.
- Many locations experience extreme tide ranges making it less likely a storm surge event will overlap with a high tide and create impacts.
- Coastal topography is steeper than other areas of the U.S., limiting areas that would be exposed to high tide flooding.
- Very few locations have tidal-to-geodetic elevation connections needed to empirically associate and map the extent and severity of inland flooding.
- Infrastructure is often placed in more protected areas away from the coast to limit exposure to extreme conditions in remote areas.
- Relative sea level is decreasing across much of Alaska due to glacial retreatment and associated uplift, making tidally-driven coastal flooding less likely in the future.
Additional details and information can be found in Patterns and Projections of High Tide Flooding Along the U.S. Coastline Using a Common Impact Threshold. Near- and real-time flood conditions can be monitored through the Coastal Inundation Dashboard.
Caribbean Islands
Regional Analysis
NOAA collects valuable oceanographic and meteorological information from water level stations across the Caribbean. Based on these long-term records, the Caribbean does not show a long-term trend in high tide flood days
- NOAA predicts a below-normal Atlantic hurricane season. El Niño conditions can suppress hurricane development in the regions, meaning stations in hurricane-prone areas will have less than average extreme weather-related flooding
2025-2026 Review
- Similar to previous years, the Caribbean region observed very little inundation related to high tide flooding. Observed flooding can be attributed to weather and storm related activity.
- La Niña conditions weren't as strong as predicted, resulting in fewer flood days at stations typically influenced by ENSO fluctuations.
Regional Flood Characteristics
- Flooding in the Caribbean Islands is less tidally driven and often the result of waves and weather events
- For this reason, minor flooding thresholds for the region are typically higher than average high tides.
- This does not preclude flooding that might occur at slightly lower heights, or flooding driven by extreme weather events, like hurricanes.
Flooding at high tide in Newport, Rhode Island.
Photo Credit: MyCoast.Org, Rhode Island, 10/20/24.
Location: Brenton Cove, King Park, Newport, Rhode Island
Cars driving along Long Neck Road between Rehoboth Bay & Indian River Bay encountered flooding due to simultaneous above normal high tide and new moon, which was exacerbated by multiple rounds of rain and onshore winds.
Photo Credit: Driscoll Drones, 2/25/2020.
Location: Long Neck Road, Millsboro, DE
Cars travel through high water on E. Bay St in front of Sanders-Clyde Elementary School in Charleston, SC. The high tide flooding was due to a perigean spring tide.
Photo Credit: Sean Bath, 9/11/2014.
Location: Charleston, SC
High tide flooding on a sunny day in St. Petersburg, Florida.
Photo Credit: Heidi Stiller, NOAA’s Office of Coast Management
Location: Coffee Pot Park, St. Petersburg, Florida. September, 2023
Persistently elevated water levels in West Bay cause high tide street flooding on Galveston Island around Jamaica Beach.
Photo Credit: Sheri Cortez, 6/25/2020.
Location: Jamaica Beach, TX
Minor high tide flooding blocks roadway on Camano Island.
Photo Credit: MyCoast, 12/30/2022
Location: Camano Island, Washington
Aerial photo of the king tide at Manzanita Junction, Mill Valley. Water levels were higher than normal due to a perigean spring tide.
Photo Credit: California Coast Commission, 12/4/2021.
Location: Manzanita Junction, Mill Valley, CA
An aerial view of the flooding during an above normal high tide in Kwigillingok.
Photo Credit: Jesse Igkurak, 6/24/2021.
Location: Kwigillingok, Bering Sea Coast, AK
Water spilling over from Makaiwa Bay into Kalahuipua'a Fishponds during an above normal high tide on July 3, 2016.
Photo Credit: Chris Peters
Location: Kalahuipua'a fishponds, at Mauna Lani Hotel, Waimea, Hawaii
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Historical Flood Days by Met Year and Projected Annual Ranges
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About the Annual 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 - a National average of 55 to 85 days per year by 2050. Predicting the frequency of high tide flooding in the future helps coastal communities plan for and mitigate flooding impacts.
The Annual High Tide Flooding Outlook provides the number of high tide flooding days predicted for the coming meteorological year (May to April). Data is supplemented with decadal projections for the year 2050, sea level rise scenarios, and high tide flood exposure maps to support long-term coastal planning. Summaries are provided for each region to account for geographical differences at the coast, and are accompanied by regional graphics to demonstrate potential high tide flooding impacts.
Using This Product
Begin by selecting a region and year from the drop down menu, or clicking a station on the map to see the number of observed and projected high tide flooding days. Click the region tab to learn more about regional drivers of higher water levels and potential high tide flooding impacts.
- Map View: Visualize high tide flooding observations and projections at NOS water level stations. Navigate the map by selecting a region from the drop-down menu or using the pan/zoom tools. Stations are color-coded to show flood frequencies for select meteorological years, the annual outlook year, and the projection for 2050.
- Region View: Learn why the annual outlook may be higher or lower than previous years for a selected region, and what coastal flooding impacts the region may experience as a result of its unique geographic characteristics.
- Station View: Interact with the current range of high tide flooding projection values and historical flood observations since 2000 to understand changes in flood frequency through time.
- Projection View: Interact with station-based decadal projections and sea level rise scenarios to understand and plan for future flooding impacts.
Underlying Science
The frequency of high tide flooding varies from year to year due to large-scale changes in weather and ocean circulation patterns, such as the phase of the El Niño Southern Oscillation (ENSO). The Annual Outlook uses a statistical model that derives a range of high tide flooding days predicted for each National Ocean Service (NOS) water level station over the coming meteorological year, May to April. The model combines historical flood observations (relative to established NOS flood thresholds) with the Oceanic Niño Index (ONI) and the 3- month average of sea-surface temperature anomalies. Decadal projections are based on a statistical fit of historical water level observations and the sea level rise scenarios outlined in the Sea Level Rise Technical Report. Each decade consists of an average of annual values calculated from data points from the previous ten years. Additional details about the methodology are detailed in Sweet, et al. 2018.
Related Resources
- High Tide Flooding Publications Archive: 2016-2023
- NOAA Technical Services Publication NOS CO-OPS 003: Notice of Services Update: Annual High Tide Flooding Outlook
- El Niño means an even floodier future is on the coastal horizon
- Guided Animation: High Tide Flooding
- NOS Ocean Fact: Perigean Spring Tides
- Video (1-minute) & NOS Ocean Fact: What is High Tide Flooding
- Another use for ENSO forecasts: predicting high-tide flooding in the U.S.