SPRING 2021: When you may experience higher than normal tides
between March and May, 2021.
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. Depending on non-tidal conditions (wind, storms, etc.), regions may experience impacts before or after
the dates mentioned here.
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.
Want to dig deeper? View the latest annual report
summarizing
high tide flooding events in 2019 and our high tide flooding outlook through April 2021.
This report is based on new, national flooding thresholds. It focuses on more impactful, deeper floods at some locations and
expands the outlook to about 100 coastal locations.
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
Dates:
March 29 - April 2, 2021
April 26 - May 1, 2021
May 24 - May 30, 2021 (The predicted tides at some locations will
be some of the highest of the year)
Locations:
Tide stations at the following locations have the greatest chance of seeing high tide
flooding:
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.
Tides will increase leading up to and after the June 21 summer solstice, due to the position of the sun relative to the earth's equator.
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?
Some of the Northeast will experience their highest tides of
2021 in May and in some locations are predicted to exceed flood thresholds from tides alone.
For March and April, high tides alone will likely not cause a
significant impact on the coast in most areas unless accompanied by a storm or strong winds.
Lower than normal low tides will also occur.
New Jersey, Delaware, Pennsylvania, Maryland, District of Columbia, Virginia
Dates:
March 28 - April 1, 2021
April 26 - April 30, 2021
May 24 - May 29, 2021 (The predicted tides at some locations will
be some of the highest of the year)
Locations:
Tide stations at the following locations have the greatest chance of seeing high tide
flooding:
The Battery, New York; Bergen Point, New York; Sandy Hook, New Jersey; Atlantic City,New Jersey; Cape May, New Jersey; Lewes, Delaware
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.
Tides will increase leading up to and after the June 21
summer solstice, due to the position of the sun relative to the earth's equator.
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?
Some of the Mid Atlantic will experience their highest tides of 2021 in May
Minor tidal flooding along the coast will occur, particularly in low-lying areas.
If a storm occurs at this time, increased levels of tidal flooding and coastal erosion may occur.
Lower than normal low tides will also occur.
North Carolina, South Carolina, Georgia, Eastern Florida coast
Dates:
March 29 - April 1, 2021
April 26 - April 30, 2021
May 24 - May 29, 2021 (The predicted tides at some locations will
be some of the highest of the year)
Locations:
Tide stations at the following locations have the greatest chance of seeing high tide
flooding:
Duck, North Carolina; Myrtle Beach, South Carolina; Charleston, South Carolina; Fort Pulaski, Georgia; Fernandina Beach, Florida
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.
Tides will increase leading up to and after the June 21
summer solstice, due to the position of the sun relative to the earth's equator.
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?
Minor tidal flooding along the coast will occur, particularly in low-lying areas.
If a storm occurs at this time, increased levels of tidal flooding and coastal erosion may occur.
Lower than normal low tides will also occur.
Texas, Louisiana, Mississippi, Alabama, Western Florida coast
Dates:
March - May, 2021
Locations:
Texas, Louisiana, Mississippi, Alabama, Western Florida coast.
Why will they be higher than normal?
The Gulf Coast will not be significantly impacted.
Why won’t they be impacted?
In many locations of the Gulf Coast, the tidal range is relatively small compared to other regions of the U.S, so they will not be as significantly impacted by a perigean spring tide.
California, Oregon, Washington State
Dates:
No dates in March and April
May 25 - May 28, 2021 (The predicted tides at some locations will
be some of the highest of the year)
Locations:
Tide stations at the following locations have the greatest chance of seeing high tide
flooding:
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.
Tides will increase leading up to and after the June 21 summer solstice, due to the position of the sun relative to the earth's equator.
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?
Minor tidal flooding along the coast, in particular in low-lying areas
If a storm occurs at this time, increased levels of tidal flooding and coastal erosion may occur
Lower than normal low tides will also occur.
Hawaii, Guam, American Samoa, Midway, Kwajalein, and Wake Island
Dates:
No dates for March
April 26 - April 30, 2021
May 25 - May 28, 2021 (The predicted tides at some locations will
be some of the highest of the year)
Locations:
Tide stations at the following locations have the greatest chance of seeing high tide
flooding:
Hawaii, Guam, American Samoa, Midway, Kwajalein, and Wake Island.
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.
Tides will increase leading up to and after the June 21
summer solstice, due to the position of the sun relative to the earth's equator.
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?
Minor tidal flooding along the coast, in particular in low-lying areas
If a storm occurs at this time, increased levels of tidal flooding and coastal erosion may occur
Lower than normal low tides will also occur.
Dates:
March 28 - April 1, 2021
April 26 - April 30, 2021
May 25 - May 29, 2021 (The predicted tides at some locations will
be some of the highest of the year)
Locations:
Tide stations at the following locations have the greatest chance of seeing high tide
flooding:
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.
Tides will increase leading up to and after the June 21
summer solstice, due to the position of the sun relative to the earth's equator.
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?
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.
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