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Monthly High Tide Flooding Outlook

A map showing the maximum daily likelihood of high tide flooding at National Water Level Observation Network stations for the selected month represented by color-coded pins. Flooding thresholds are supplied by NOAA’s Office for Coastal Management.

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Northeast Outlook

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.

Visit the NOAA Coastal Inundation Dashboard for this region to view real-time water levels with forecasts out to 48 hours
High tide flooding pushes water onto a walkway along the Boston waterfront near India Wharf, Boston, MA.

High tide flooding pushes water onto a walkway along the Boston waterfront near India Wharf.

Photo Credit: MyCoast.org, 10/18/2016.

Location: Near India Wharf, Boston, MA

Flodding Millsboro, Deleware

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 Charleston, South Carolina

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

Flooding on street in Galveston Island Texas

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

Aerial photo of king tide at Manzanita Junction, Mill Valley, California

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, Alaska

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

The intersection of Kilihau street and Kakoi street is flooded with water during high tide. Above normal water levels were due to a perigean spring tide and swells from Hurricane Erick

The intersection of Kilihau street and Kakoi street is flooded with water during high tide. Above normal water levels were due to a perigean spring tide and swells from Hurricane Erick.

Photo Credit: kingtide@hawaii.edu, 8/1/2019.

Location: Mapunapuna, HI

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A flooding likelihood calendar is not available for this station. For information about when the highest astronomical tides are likely to occur during the selected month, please visit the tide predictions for this station here.

Likelihoods are relative to flood threshold of ### feet above MHHW

Flood Likelihood:

  • Unlikely
  • Possible
  • Likely
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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.

  1. 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%)
  2. 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.
  3. 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.

Underlying Science

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.

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