Storm surge

A storm surge reflects the difference between the actual water level under the influence of a meteorological disturbance (storm tide) and the level which would have occurred in the absence of the meteorological disturbance (WMO, 2008, 2011, 2017).

A storm surge is the rise in seawater level caused solely by a storm. It is the abnormal rise in seawater level during a strom, measures as the height of the water above the normal predicted astronomical tide. The surge is caused primarily by a storm's winds pushing water onshore.

Storm surge should not be confused with storm tide. A storm tide is the water level that results from the combination of the storm surge and the normal (astronomical tide).

This rise in water level can cause extreme flooding in coastal areas, resulting from storm tides reaching up to 6 meters (20 feet) or more in some cases (NOAA, 2019b.) On top of a strom tide are pounding waves generated by the powerful winds. The area of seawater flooding may extend along the coast for over 100 km, with water pushing several kilometres inland if the land is low lying. The combined effects of the storm tide and surface waves can destroy buildings, wash away roads and run ships aground (Australian Government, 2020).

Examples of National Alerting Parameters include storm surge warning issued in Canada (Government of Canada, 2019) and an Advisory for storm surge watch/warning issued by the World Meteorological Organization (WMO, 2017).

Different symbols of hazards and disasters.

See all hazards

Latest Storm surge additions in the Knowledge Base

Update

18 January 2023

California’s storms are almost over. Its reckoning with flood insurance is about to begin

California has nearly seen the last of the relentless sequence of storms that inundated the state since late December, leading to tens of thousands of evacuations, at least 20 deaths, and an estimated $1 billion in damages.

Grist Magazine

Documents and publications

18 January 2023

ComEd Climate risk and adaptation outlook, Phase 1: Temperature, heat index, and average wind

This report presents the most up-to-date understanding of how climate change may affect ComEd’s distribution grid and highlights the need for strategies that adapt to future climate conditions.

Update

17 January 2023

Extreme storms and flood events cause damage worth billions to ports – and they are most disruptive to small island developing states

Shipping ports are crucial for the global economy. They handle the majority of trade, and transportation hubs and provide employment. Ports are located in coastal areas or on large rivers and are exposed to natural hazards such as storms and floods.

Conversation Media Group, the

Damaged bridge after the floods in the Ahr valley in Germany in 2021.

Update

11 January 2023

Atmospheric rivers over California’s wildfire burn scars raise fears of deadly mudslides – this is what cascading climate disasters look like

Rivers of muddy water from heavy rainfall raced through city streets as thousands of people evacuated homes downhill from California’s wildfire burn scars amid atmospheric river storms drenching the state in early January 2023.

Conversation Media Group, the

Update

28 December 2022

How a deadly storm turned a French resort into a climate change laboratory

Xynthia was a perfect storm of hurricane-force winds, surging seas and driving rain that smashed into the western coasts of France and Spain overnight, wreaking havoc as far inland as Germany.

Euronews

Research briefs

7 December 2022

Linking African winds to Atlantic storms

Simulations suggest that waves in the atmosphere above northern Africa influence the intensity, timing, and location of formation of Atlantic tropical cyclones.

Eos - AGU

Research briefs

5 December 2022

The Southern Hemisphere is stormier than the Northern, and we finally know why

UChicago research offers first concrete explanation for difference, and show it is getting even stormier over time

University of Chicago

Update

28 November 2022

Government of Liberia and partners launch implementation of Coastal Resilience Project in Sinoe

The Government of Liberia through the Ministry of Mines and Energy and the Environment Protection Agency with support from UNDP on 25 November 2022 formally launched the implementation of the Sinoe coastal resilience project during an inception workshop.

United Nations Development Programme (UNDP)