What is a storm surge and why is it so dangerous?

2019-05-04 09:52
Indian people look out towards the sea from a closed beach in Puri in the eastern Indian state of Odisha. (Dibyangshu Sarkar, AFP)

Indian people look out towards the sea from a closed beach in Puri in the eastern Indian state of Odisha. (Dibyangshu Sarkar, AFP)

Multimedia   ·   User Galleries   ·   News in Pictures Send us your pictures  ·  Send us your stories

Severe cyclone Fani, which blasted ashore on Friday in India, is expected to pack a frequently underestimated yet lethal threat: Storm surge.

The surge happens when sea levels rise dramatically during a storm, sending a destructive wall of water gushing over people and property on land.

Here are key questions and answers on the phenomenon:

How does it work?

Storm surge is not the result of rainfall or flooding, rather it happens when powerful winds push ocean water rushing toward land.

The phenomenon is an "abnormal rise of water generated by a storm, over and above the predicted... tides", according to the US National Oceanic and Atmospheric Administration (NOAA).

Indian forecasters said a surge of 1.5m could hit the eastern state Odisha, where the monster cyclone is forecast to make landfall.

Why is it so dangerous?

In previous storms, people have failed to flee because they did not grasp the storm surge's deadly threat.

That was the case for 2013's Super Typhoon Haiyan, which left 7 350 dead or missing in the central Philippines, primarily due to the surge.

A wall of water estimated to be 7.5m high, blasted into coastal towns like Tacloban, a city of 240 000 people.

Also, surges can extend for dozens of kilometres inland, overwhelming buildings quickly and cutting off roads. People can end up drowning in their cars or homes.

The walls of water can begin before storms even make landfall, making it harder to sound the alarm in time to save lives.

What are the contributing factors?

The power of a surge is dictated by factors including a storm's size and intensity, as well as the geography of the coastline and sea level.

Bays tend to funnel the surge, pushing water to higher levels, according to the Hong Kong Observatory.

Tacloban, the worst hit city in Haiyan, sits less than 5m above sea level.

The town and others nearby were defenceless against the surge that was also funnelled through a shallow bay sandwiched between neighbouring islands.

Rising seas and warming oceans due to climate change are also expected to amplify the effects of storm surge in the coming decades.

Numerous studies have predicted that storm surges will become more frequent and deadly as the planet warms.

Can we protect against storm surge?

One of the best protections is clear, early warnings to people in the surge's sights and evacuations to areas of higher elevation.

Low-lying areas like the US state of Louisiana have also long used levees as a measure of protection against flooding and, by extension, storm surge.

However, most of the 1 800 deaths from Hurricane Katrina, which struck the US Gulf Coast in 2005, are attributed to storm surge, NOAA said.

Eighty percent of New Orleans found itself submerged when the levees that surround it broke and the water rushed in.

KEEP UPDATED on the latest news by subscribing to our FREE newsletter.

- FOLLOW News24 on Twitter

Read more on:    india  |  weather

Join the conversation!

24.com encourages commentary submitted via MyNews24. Contributions of 200 words or more will be considered for publication.

We reserve editorial discretion to decide what will be published.
Read our comments policy for guidelines on contributions.

Inside News24

Traffic Alerts
There are new stories on the homepage. Click here to see them.


Create Profile

Creating your profile will enable you to submit photos and stories to get published on News24.

Please provide a username for your profile page:

This username must be unique, cannot be edited and will be used in the URL to your profile page across the entire 24.com network.


Location Settings

News24 allows you to edit the display of certain components based on a location. If you wish to personalise the page based on your preferences, please select a location for each component and click "Submit" in order for the changes to take affect.

Facebook Sign-In

Hi News addict,

Join the News24 Community to be involved in breaking the news.

Log in with Facebook to comment and personalise news, weather and listings.