Cooper River at Charleston Harbor (IN MLLW)

The past week

What floods at each level

• 12.52 ft

  Record tide level reached in association with Hurricane Hugo which made landfall at Sullivans Island, SC as a Category 4 hurricane at midnight September 22nd, 1989.

• 10.23 ft

  Peak tide level reached in association with an unnamed hurricane that made landfall near Hilton Head Island, SC as a Category 2 hurricane on August 11th, 1940.

• 9.92 ft

  Peak tide level reached in association with Tropical Storm Irma on September 11th, 2017.

• 9.86 ft

  Peak tide level reached in association with a strong area of low pressure on December 17th, 2023. Ranks as the highest non-tropical tide level on record.

• 9.29 ft

  Peak tide level reached in association with Hurricane Matthew which made landfall near McClellanville, SC as a Category 1 hurricane on October 8th, 2016.

• 9.23 ft

  Peak tide level reached in association with Tropical Storm Idalia on August 30th, 2023.

• 8.64 ft

  Peak tide level reached in association with Hurricane David which made landfall near Sapelo Island, GA as a Category 1 hurricane on September 4th, 1979.

• 8.15 ft

  Peak tide level reached in association with an unnamed hurricane that made landfall near Ossabaw Island, GA as a Category 2 hurricane on October 15th, 1947.

• 8.14 ft

  Peak tide level reached in association with Hurricane Gracie which made landfall near Edisto Island, SC as a Category 4 hurricane on September 29th, 1959.

• 8 ft

  At 8.0 ft MLLW, major coastal flooding occurs. Widespread flooding occurs in Downtown Charleston with numerous roads flooded and impassable and some impact to structures. Impacts become more extensive all along the southeast South Carolina coast including erosion at area beaches, with limited or no access to docks, piers, and some islands.

• 7.5 ft

  At 7.5 ft MLLW, moderate coastal flooding occurs. In Downtown Charleston, additional impacted roads include HW-17 at HW-61, Market Street, East Bay, Rutledge, and areas around MUSC. Other impacted areas include Long Point Road near Palmetto Islands County Park, locations around the Naval Complex, 12th and 15th Streets on Isle of Palms, and the road leading to Bohicket Marina on Seabrook Island. In Beaufort County, flooding will impact Hunting Island and the Sea Island Parkway near Chowan Creek Bridge.

• 7 ft

  At 7.0 ft MLLW, minor coastal flooding typically begins. Minor flooding on roadways around Downtown Charleston occurs, possibly including Lockwood Drive, Wentworth and Barre, Fishburne and Hagood, and Morrison Drive. As the tide height approaches 7.5 ft MLLW, roads can become impassable and closed. Other impacts outside of Downtown Charleston include minor flooding of low-lying locations near area beaches including Isle of Palms, Sullivan's Island, Folly Beach, Kiawah Island, and Edisto Island.

Highest crests on record

When the water runs low

• -1.5 ft

  At -1.5 ft MLLW, very low water levels will occur along the southeast South Carolina coast. This could cause navigation issues along the coast including tidal creeks, inlets, and in marsh areas. Also, areas that are normally under water could be exposed.

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