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Answer: Storm surge is the abnormal rise in sea level caused by a storm, mainly its winds pushing water ashore, measured above the normal predicted tide. Storm tide is the total water level: surge plus tide. NOAA calls surge the greatest threat to life in a hurricane.

How surge forms

Winds circling a hurricane drive a vertical circulation in the ocean. In deep water nothing blocks it, so there is little sign of surge. Near the coast the shallow bottom disrupts the circulation and water is forced up and inland.

What makes it bigger

• Stronger winds.
• Coastline shape relative to the storm track.
• Storm size, speed and intensity.
• Local bathymetry (water depth).
• Timing with high tide, especially near new and full moons.

Where it reaches

All U.S. East and Gulf coast locations are vulnerable, and surge can travel up rivers and canals. NOAA's National Hurricane Center publishes surge hazard maps.

Claims

• id: C1 claim: Storm surge is the rise in seawater level caused solely by a storm. source: S1 evidence: "Storm surge is the rise in seawater level caused solely by a storm."
• id: C2 claim: Storm tide combines storm surge and normal high tide. source: S1 evidence: "which is the combination of storm surge and normal high tide"
• id: C3 claim: Storm surge is primarily caused by strong onshore winds. source: S2 evidence: "Storm surge is primarily caused by the strong onshore winds of a hurricane or tropical"
• id: C4 claim: Stronger winds produce a higher storm surge. source: S2 evidence: "Stronger winds will produce a higher storm surge."

Sources

• [S1] What is storm surge?. NOAA. https://oceanservice.noaa.gov/facts/stormsurge-stormtide.html . License: US government work, public domain. Accessed 2026-11-04.
• [S2] Storm Surge Overview. NOAA. https://www.nhc.noaa.gov/surge/ . License: US government work, public domain. Accessed 2026-11-04.

License: this note is CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Summary by iinventedlight (AI-assisted).

@misc{iil_note_sm5y6abq,
  author = {{iinventedlight}},
  title = {{Storm surge and storm tide}},
  howpublished = {iinventedlight Library},
  year = {2026},
  date = {2026-11-04},
  url = {https://iinventedlight.com/library/notes/storm-surge/},
  note = {Permanent ID iil:note:sm5y6abq. License: CC-BY-4.0.},
}

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