Fall 2021: When you may experience higher than normal tides
between September and November 2021.
The rising and falling of the sea is a phenomenon upon which we can always depend. Tides are the regular rise and fall of the sea surface caused by the gravitational pull of the moon and sun and their position relative to the earth. There are some factors that cause the tides to be higher than what is "normally" seen from day to day. This bulletin tells you when you may experience higher than normal high tides for the period of time between September and November 2021.
We also publish annual high tide flooding reports that present a broad outlook of what to expect for a given year in terms of high tide flooding, as well as a summary of high tide flooding events for the previous calendar year.
Higher than normal high tides alone do not necessarily cause coastal flooding. However, they are becoming increasingly impactful due to continued sea level rise. High tide
flooding that inundates busy streets, and washes out beaches is more likely to occur during these periods depending on your location along the coast. More severe flooding may result if adverse weather — heavy rains, strong wind or big waves — conditions are present.
Select your region to see when you may experience higher than normal tides that may cause flooding.
The NOAA Coastal Inundation Dashboard provides real-time water levels with forecasts out to 48 hours for all tidal stations.
View an archive of past high tide flooding dates for all regions.
CO-OPS is the NOAA tides and currents office.
Print or save this bulletin as a PDF document.
Maine, New Hampshire, Massachusetts, Rhode Island, Connecticut, and New York
No dates in September
Tide stations at the following locations have the greatest chance of seeing high tide
Bar Harbor, Maine; Portland, Maine; Boston, Massachusetts; Providence, Rhode Island; Kings Point, New York
A perigean spring tide will be occurring. This is when the moon is either new or full and closest to earth. Higher than normal high tides and lower than normal low tides will occur.
What kind of impact might I expect along the coast?
Due to the topography, in particular for southeast Alaska (less low lying areas), tidal flooding will generally not have a significant impact on the coast unless there is a severe storm.
Lower than normal low tides will also occur.
No dates September - November, 2021
Puerto Rico and U.S. Virgin Islands.
Why will they be higher than normal?
These regions will not be significantly impacted.
Why won’t they be impacted?
For Puerto Rico and the U.S. Virgin Islands, the tidal range is relatively small compared to other regions of the U.S, so these locations will not be significantly impacted by a perigean spring tide. However, local flooding may occur due to wave, rainfall, and elevated groundwater effects — particularly if there is a severe storm.
Coastal Inundation Dashboard
View real-time and historic coastal flooding information.