Definition of Surge Weather
Surge is the type of atmospheric process that operates inland water or oceans. In this weather, the gravitational tides and the atmospheric pressure work together to create dramatic effects in the inland water or on the coastal. These effects will also lead to flooding in many areas. The difference in the velocity of the winds changes the circulation of the oceans for creating the dramatic effect. When we define surge, you should know that it will leave its impact over a vast area.
To answer what is the meaning of Surge the meteorological department has attempted to define it clearly. According to them, Surge is associated with tropical storms and tropical cyclones. These two are the types of storm surges. These storms are generated over the local inland seas and lakes. There are several high-pressure areas that you can find on the Earth, such as the northern and southern Atlantic oceans. In this high-pressure area, you will commonly find the changes in atmospheric pressure when a surge is forming. If you think, what is the meaning of surge, or how it happens? Then there is a simple answer to this question. It concerns the atmospheric pressure that develops on oceans and the waters inland.
Surge Formation
When the atmospheric pressure changes in the area of high pressure, it will lead to the fall in water level in that area; however, when the atmospheric pressure changes in the sea of low pressure, the water level will rise. There are several areas in which this weather occurs from time to time, and they noted the common measurement of rising or fall of water level. You will commonly see the 2millibars rise or fall in water level in 24 hours.
If we see the surge definition, then you will understand that this is the type of atmospheric process which can be caused by different situations. Another cause that can create surges is the sudden increase in the speed of wind streams. This type of surges will happen in tropical areas, and you can also follow this surge in the weather map with the expansion when the speed of the wind changes in the trade wind belt. It is commonly increased by 40 km/hr from the surface area to over some height from the surface. When these changes happen in the monsoon currents, then the changes in the speed of wind are called the monsoon surge or burst.
The surges can also happen on a smaller scale, but the impacts of the surges on a smaller scale will be harsh than normal. The increase in the level of water will be unpredictable when it comes to the smaller scale. It will cause flooding in the coastal areas, and it will also destroy the lives of many people. If the tropical storms and tropical cyclone is formed, then it will make landfall across the coast. The storm surges will also bring heavy rain along with them. The height of the storm is also measured based on its wind speed, intensity, and path. It also depends upon the characters of the coastal region, such as shape, shore, and slope.
There are two main types of surge weather you will find from several studies. Following is detailed information on the types of the surge and how they formed.
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Storm Surge
We can define surge as a process that mainly occurs in the Ocean and inland water due to the variation in pressure, gravitational tides, and other changes in oceanic circulation. Storm surge is one of the types of surge weather which is commonly found in the inland seas or tropical region. Storm surge meaning is very simple, which is the sudden increase in the water level in the low-pressure areas. Storm surge is similar to coastal floods and the different tsunami-like phenomenon. For the measuring of storm surge intensity, you just have to measure the level of rising water concerning the normal tidal level of the water. You should also know that in the concept of storm surge, you will not find any waves or drama in the oceanic circulation.
When the coastal region is hit with tropical cycling or a storm surge, it will damage all the infrastructure on the coastal region, and it will leave a huge impact on the coast. When the weather becomes more intense and the level of water increases, then the impact of the surge is more on the infrastructure and the property on the coastal area. It will also create a high impact on the coat population.
Surge definition is similar to the storm surge or tidal surge. The impacts of the storm surge are extreme. It will also lead to extreme floods and tsunami. This will damage all the infrastructure and the property which is in the path of the surge.
You will find several effects which will contribute to forming the surge, or it will affect the intensity of the surge in many ways. Direct wind effect, atmospheric pressure effect, heart rotation effect, the effect of waves, rainfall effect, the depth of the sea or topography, and storm size all will affect the surge, and it will also help in increasing the intensity of the storm surge. Every factor has its mechanism to work with the surge.
All the above information will give a detailed answer to the question: what is surge? You will also see the different impacts and the factors which affect the formation of a surge in different low-pressure areas.
FAQs on Storm Surge
1. What is a storm surge in Geography?
A storm surge is an abnormal rise in the sea level along a coast, caused by the forces of a major storm, such as a cyclone or hurricane. It is the rise in water level over and above the predicted astronomical tide. This phenomenon is primarily driven by the storm's powerful winds pushing water towards the shore and the low atmospheric pressure at the storm's centre, which allows the sea surface to bulge upwards. It is a major cause of coastal flooding and destruction during cyclonic events.
2. What are the main meteorological factors that cause a storm surge?
The formation and intensity of a storm surge are primarily caused by two meteorological factors associated with a cyclone:
Wind Effect: This is the most significant factor. The strong, persistent winds of a storm blow across the sea surface, piling up water and pushing it towards the coastline. The continuous force of the wind causes the sea level to rise significantly as it approaches the shore.
Pressure Effect: The centre of a tropical cyclone has extremely low atmospheric pressure. This lower pressure on the sea surface allows the water below to rise up, creating a dome of water. For every one-millibar drop in pressure, the sea level can rise by approximately 1 cm.
3. How is a storm surge different from a tsunami?
While both storm surges and tsunamis cause coastal flooding, they are fundamentally different phenomena. The key difference lies in their cause:
Origin: A storm surge is a weather-related event caused by strong winds and low pressure from a cyclone or hurricane. A tsunami is a geological event, typically caused by underwater earthquakes, volcanic eruptions, or landslides.
Duration and Arrival: A storm surge builds gradually as the storm approaches and can last for several hours. A tsunami arrives as a series of powerful, fast-moving waves, often with very little warning.
Scale: A storm surge is a more localised event, affecting the coastline in the path of the storm. A tsunami can travel across entire ocean basins, affecting coastlines thousands of kilometres away from its source.
4. Why are storm surges considered one of the most dangerous aspects of a cyclone?
Storm surges are extremely dangerous due to their immense destructive power and widespread impact. The primary reasons include:
Massive Flooding: They can rapidly inundate vast low-lying coastal areas with several metres of water, submerging homes, infrastructure, and agricultural land.
Destructive Force: The sheer weight and force of the moving water, combined with storm-driven waves on top of the surge, can demolish buildings, wash away roads and bridges, and cause extreme coastal erosion.
High Fatality Rate: Historically, the majority of deaths during tropical cyclones are due to drowning in the storm surge.
Long-Term Damage: The intrusion of saltwater can contaminate soil and freshwater sources, making land unsuitable for agriculture and drinking water scarce for a long time after the event.
5. Which geographical factors can make a storm surge more severe in a particular area?
Beyond the storm's intensity, certain geographical features can significantly amplify the height and impact of a storm surge:
Shape of the Coastline: Coastlines that are concave or funnel-shaped, such as a bay or estuary, can concentrate the incoming water, leading to a much higher surge. The Bay of Bengal is a prime example of this.
Shallow Continental Shelf: A wide and gently sloping offshore sea floor (continental shelf) allows the wind to pile up water more effectively than a steep, deep-water coast. This leads to a higher surge at the coast.
Tidal Timing: The most destructive scenario occurs when the storm surge coincides with a natural high tide. The total water level (storm tide) becomes dangerously high, leading to catastrophic flooding.
6. Can you provide an important example of a storm surge event in India?
A classic and devastating example of a storm surge in India is the one caused by the 1999 Odisha Super Cyclone. This storm generated a massive surge that reached heights of up to 9 metres (nearly 30 feet) in some areas. The surge travelled more than 20 kilometres inland, completely submerging vast coastal plains. This event highlighted the immense destructive capability of storm surges, as it was responsible for the majority of the nearly 10,000 fatalities and the large-scale destruction of property and livelihoods in coastal Odisha.
