A storm surge is a temporary and abnormal rise in sea level caused by a combination of strong winds and low atmospheric pressure associated with a storm, such as a tropical cyclone or a hurricane. Storm surges pose significant hazards to coastal areas, leading to coastal flooding, erosion, and potential damage to infrastructure and communities.
1. Components of Storm Surge
a. Factors Contributing to Storm Surge
- Wind: Strong onshore winds, typically associated with the circulation of a tropical cyclone or hurricane, push water towards the coast.
- Low Pressure: The low atmospheric pressure at the center of the storm can cause the sea surface to bulge upwards.
- Geomorphology: The shape of the coastline and underwater terrain can amplify or diminish the effects of a storm surge. For example, shallow coastal areas can experience greater inundation compared to steep or rocky coastlines.
b. Timing and Duration
- Timing: Storm surges typically occur as the storm makes landfall or passes close to the coastline, coinciding with high tide for maximum impact.
- Duration: The duration of a storm surge depends on the speed of the storm and the timing of its arrival relative to the tidal cycle.
c. Height and Impact
- Height: The height of a storm surge can vary widely depending on the size and intensity of the storm, ranging from a few feet to over 20 feet (in extreme cases).
- Impact: Storm surges can lead to coastal inundation, flooding of low-lying areas, erosion of beaches and dunes, and damage to buildings and infrastructure near the coastline.
2. Examples of Storm Surge
a. World Examples
- Hurricane Katrina (2005):
- Location: Gulf Coast of the United States (Louisiana, Mississippi, Alabama).
- Impact: Katrina generated a storm surge of up to 28 feet along the Mississippi coast, leading to catastrophic flooding in New Orleans and other coastal areas.
- Super Typhoon Haiyan (2013):
- Location: Philippines.
- Impact: Haiyan produced a storm surge of over 20 feet, causing extensive damage and loss of life in Tacloban City and other coastal communities.
b. India Examples
- Cyclone Phailin (2013):
- Location: Odisha and Andhra Pradesh coasts.
- Impact: Phailin generated a storm surge of about 3-4 meters, causing significant coastal inundation and damage to infrastructure, although timely evacuations helped minimize casualties.
- Cyclone Amphan (2020):
- Location: Eastern coast (West Bengal and Odisha).
- Impact: Amphan produced a storm surge of up to 5 meters, inundating coastal areas and causing widespread damage to homes, infrastructure, and agriculture.
3. Mitigation and Preparedness
- Early Warning Systems: Meteorological agencies use advanced forecasting models to predict storm surge heights and issue warnings to coastal communities.
- Evacuation Plans: Coastal communities are encouraged to have evacuation plans in place to move residents to higher ground or shelters before the arrival of a storm surge.
- Infrastructure: Building codes and infrastructure designs in coastal areas may incorporate measures to withstand or mitigate the impact of storm surges, such as seawalls, flood barriers, and elevated buildings.
Conclusion
Storm surges are dangerous phenomena associated with tropical cyclones and hurricanes, causing coastal flooding and significant damage to communities and ecosystems. Understanding the components of storm surges, their causes, and examples from around the world, including India, highlights the need for preparedness, early warning systems, and infrastructure resilience to minimize the impact of these hazardous events on coastal populations.
