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

Research briefs

24 July 2023

Long-term changes in waves and storm surges have not impacted global coastlines

Changes in ocean wave and storm conditions have not caused long-term impacts on sandy coastlines in the past 30 years, a new study has found.

University of Melbourne

Street corner in Beijing during a Sandstorm.

Update

18 July 2023

China and Mongolia team up to fight sandstorms

Mining and climate change are damaging the grasslands that prevent sandstorms. Can greater cooperation help?

China Dialogue

Update

12 July 2023

WMO highlights efforts to tackle sand and dust storms

The World Meteorological Organization is supporting the first ever International Day of Combating Sand and Dust Storms to draw attention to the significant impacts on the environment, socio-economic well-being and health.

World Meteorological Organization (WMO)

Aerial view of coastline of the Seychelles.

Update

12 July 2023

Climate threat: Rising sea levels and stronger storms highlight the need for coastal resilience

Climate change is threatening coastal communities worldwide. Using local knowledge, as well as innovative practices such as parametric insurance, is needed to enhance coastal resilience and mitigate the impact of climate change.

Asian Development Bank (ADB)

Starting sand storm in desert of high altiude with cumulonimbus rain louds.

Update

12 July 2023

Launch of the SDS Toolbox of the UNCCD on the International Day of Combating Sand and Dust Storms (SDS)

The frequency of sand and dust storms (SDS) is on the rise in various regions across the globe. This rise is attributed to factors such as human-driven climate change, desertification, land degradation, and persistent droughts.

United Nations Convention to Combat Desertification (UNCCD)

Documents and publications

13 July 2023

Sand and dust storms compendium: Information and guidance on assessing and addressing

The aim of the Compendium is to provide information and guidance on how to assess and address the risks posed by sand and dust storms and plan actions to combat sand and dust storms.

Update

2 May 2023

Sand dunes offer clues to coastal erosion and how to prevent it

The management of these natural barriers through the ages could hold lessons for coping with climate change and rising sea levels today.

European Commission

Update

22 June 2023

How oysters are helping protect Apalachicola’s vulnerable shoreline

This nature-based solution involves creating up to 20 acres of engineered oyster reefs and up to 30 acres of salt marshes to attenuate wave action and help protect the vulnerable coastline and critical infrastructure from erosion.

United Nations Framework Convention on Climate Change (UNFCCC)