High Tide Bulletin: Fall 2017

When you may experience higher than normal tides from September through November 2017.

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 2017.

Regional outlook map

Select a region below to see when you may experience higher than normal tides from September-November 2017. Depending on non-tidal conditions (wind, storms, etc.) regions may experience impacts before or after the dates mentioned here.

NOTE: Higher than normal high tides alone do not necessarily cause coastal flooding. However, higher-than-normal high tides are becoming increasingly impactful due to continued sea level rise. High tide flooding that causes a nuisance along the coast (such as flooded streets, washed 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.  

West Coast Outlook

Includes California, Oregon, Washington State

When will the tides be higher than normal?

  • In September, October and November, water levels will not be significantly impacted by the Perigean Spring Tide.

Why won’t they be higher than normal?

  • The timing of the perigee is not closely aligned with the full or new moon, reducing the overall effect of the perigean spring tide.

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Regional outlook (Text only)

Northeast outlook

Includes Maine, New Hampshire, Massachusetts, Connecticut, and New York

When will the tides be higher than normal?

  • November 4-6

Why will they be higher than normal?

  • Mean sea level is generally higher in the early fall months in the northeast due to warmer, expanding ocean water and changes in weather patterns.
  • 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 of the northeast (less low lying areas), tidal flooding will not likely cause a significant impact on the coast unless accompanied by storm or strong winds.

Where might I expect high tide flooding?

  • Areas near the tide station at Kings Point, NY have the greatest chance of seeing high tide flooding.

Mid-Atlantic outlook

Includes New Jersey, Delaware, Pennsylvania, Maryland, District of Columbia, Virginia

When will the tides be higher than normal?

  • October 7-9, November 4-7

Why will they be higher than normal?

  • Mean sea level is generally higher in the early fall months in the Mid Atlantic due to warmer, expanding ocean water and changes in weather patterns.
  • In November, 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?

  • 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.

Where might I expect high tide flooding?

  • Areas near the tide station at Cape May, NJ have the greatest chance of seeing high tide flooding.

Southeast outlook

Includes North Carolina, South Carolina, Georgia, Eastern Florida coast

When will the tides be higher than normal?

  • September 17-19, October 7-10, November 3-8

Why will they be higher than normal?

  • Mean sea level is generally higher in the fall in the Southeast due to changing weather patterns and a decrease in Gulf Stream transport.
  • In November, 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?

  • 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

Where might I expect high tide flooding?

  • Tide stations at the following locations have the greatest chance of seeing high tide flooding - Wilmington, NC; Beaufort, NC; Charleston, SC; Fort Pulaski, GA.

Gulf Coast outlook

Includes Texas, Louisiana, Mississippi, Alabama, Western Florida coast

When will the tides 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.

West Coast outlook

Includes California, Oregon, Washington State

When will the tides be higher than normal?

  • In September, October and November, water levels will not be significantly impacted by the Perigean Spring Tide.

Why won’t they be higher than normal?

  • The timing of the perigee is not closely aligned with the full or new moon, reducing the overall effect of the perigean spring tide.

Hawaii and the Pacific Islands outlook

Includes Hawaii, Guam, American Samoa, Midway, Kwajalein, and Wake Island

When will the tides be higher than normal?

  • In September, October and November, water levels will not be significantly impacted by the Perigean Spring Tide.

Why won’t they be higher than normal?

  • The timing of the perigee is not closely aligned with the full or new moon, reducing the overall effect of the perigean spring tide.

ALASKA outlook

When will the tides be higher than normal?

  • November 4 - 7

Why will they be higher than normal?

  • 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 of Alaska (less low lying areas), tidal flooding will generally not have a significant impact on the coast unless there is a severe storm.