NOTES ON CYCLONES, CH 8, CLASS 7

 

Clouds are formed due to water vapour in the air.
As the water turns into vapour, it takes up the heat from the atmosphere.
When the water vapour turns into clouds and falls back as raindrops the same heat is released back into the atmosphere.
This heat warms up the air around the raindrops and the warm air starts rising.
This leads to decreasing their pressure in the region.
So, the air from the surroundings takes the place of the warm air. This cycle continues until the rain falls.
As a result, a very low-pressure region is created and strong winds start revolving in that low-pressure region. This is the condition of a cyclone.
The formation of a cyclone that depends upon different factors:
the temperature of the place
the wind speed
the direction of the winds
the humidity of the place
Figure 7 Formation and Structure of A Cyclone
Structure of a Cyclone
Cyclone is a rotation of air in the atmosphere at a height of around 10 to 15 km.
The centre of the cyclone(also called the eye of the storm) is a clean area where there are no clouds but only light winds.
This area ranges from 10 to 30 km in diameter.
The cloud region lies around this eye and has a diameter of around 150 km.
The cloud region has high-speed winds blowing at 150 to 250 km per hour accompanied by heavy rainfall.
The first indication of a cyclone can be observed when strong winds start flowing and pushing away the water from the shores.
The destruction caused by a cyclone
Cyclone can result in extremely high waves in the sea or ocean because of the low pressure. These waves can be 3 to 12m high.
When these high waves hit the shore it results in the destruction of life and property to a great extent.
The soil of the area also loses its fertility after a cyclone.
Floods can appear if rainfall continues for a longer duration.
High-speed winds in the cyclone affect the telephonic communication lines, uproot trees, damage houses and cause loss of life.
Other names of a cyclone
Hurricane – American continent
Typhoon – Japan and the Philippines
Figure 8 Different types of Cyclones
Tornado
A tornado is a weather condition when a cloud having a dark funnel-shape reaches the ground.
The diameter of a tornado can range from one meter to several kilometres.
The tornadoes can be formed within cyclones as well.
In a tornado, winds blow at high speed of 300 km per hour.
The funnel-like shape of a tornado sucks everything that comes near it at the base because of the low pressure exerted by the winds.
It then throws the things upwards. Hence, tornados can be devastating.
Figure 9 Formation of Tornado
Protecting yourself from a tornado
To protect oneself in a tornado one should take shelter in an underground room with no windows.
If in a room with windows, one should close them and hide under a table or a workbench.
One should bow down on the knees protecting their neck and head using their arms.
Figure 10 Protecting yourself from a tornado
Safety measures for cyclones
There should be a cyclone forecasting service that can want the people of a particular area that can be hit by a cyclone.
The speed of winds plays a major role in predicting any calamity like cyclones hence the speed of wind in coastal areas should be measured regularly. Anemometer is a device that can measure the speed of the Wind.
Figure 11 Anemometer
The warnings should be communicated rapidly to the citizens, ships that are sailing in the sea, government agencies and fisherman as well.
Along with this, cyclone shelters should be built in coastal areas and agencies should be appointed who can help the people at the time of calamity.
How individuals can protect themselves from cyclones
One should not ignore the warnings given by the weather forecasting team. If you can, you must move to safe places and carry all your important belongings with you.
One should not drive on roads that have standing water as they might be damaged.
One should keep all the emergency numbers with themselves so that they can seek help when required.
Figure 12 Protecting yourself during a cyclone
What to do if you are living in a cyclone hit area
The water in such region can be contaminated. Hence one should make sure if the water is safe and only then drink it.
One should stay away from power lines for electrical switches of any kind.
One should stay at home or at the shelters and should not move out unnecessarily.
One should not put unnecessary demands to the rescue team and should co-operate with them.
One should help each other in such a situation.
Role of Technology in predicting and protecting from the cyclone
The satellites and radars have made it possible to predict cyclones ahead of time so that appropriate precautionary measures can be taken accordingly.
There are now several National and international organizations that monitor cyclone-related issues.
Generally, a cyclone watch or a cyclone and alert is issued every 48 hours in advance if a storm is expected in an area.
Then a cyclone warning is issued before 24 hours. This warning is then broadcasted in the area after intervals of half an hour or 1 hour.