1.2 Tropical cyclones

Assessment

Memorandum

Activity 1:

1. The effects of tropical cyclones:

• Loss of lives among human beings and animals;
• Rivers overflow and towns near rivers are also flooded or even destroyed;
• Decaying bodies cause pollution and health hazards;
• Bridges and roads are washed away;
• Electricity, water and sewage services are interrupted;
• Houses and other buildings are destroyed or severely damaged;
• Crops are destroyed;
• Gale force winds blow away roofs and uproot trees and shrubs. This is also dangerous as people might get injured;
• No fresh water or food. This leads to famine and death.

1. Tropical cyclones originate in warm, humid tropical oceans. The strong winds cause gigantic waves in the oceans. These waves flood the coastal areas and cause enormous damage.

As soon as the tropical cyclone reaches the land, it has no warm, humid sea air to thrive on, and it dies away. That’s why there will still be gales for quite a time, but they subside as the cyclone dies.

1. The area of calm, cloudless skies in the middle (centre) of a tropical cyclone is called the “eye”. It has a width of about 35-50 km. Here the pressure is less than 1 000 kPa. The area directly around the eye is where the strongest gales occur.

Activity 2:

• During tropical cyclones most deaths occur because of the floods. Rivers that suddenly come down may unexpectedly flood a region.
• Some people try to cross a river which is in flood and are washed away by the water masses.
• Gale force winds that blow away roofs and other items, may also cause deaths.
• However, once the storm has passed, most deaths occur because of water pollution, health hazards, hunger and thirst.

Activity 3:

1. EMERGENCY SERVICES

1. Fire rescue teams must set out to extinguish possible fires.
2. Immediately start searching for bodies and animal carcasses.
3. Take fresh water and food supplies to be handed out to the people.
4. Take medical teams and supplies to treat the injured. Erect emergency hospitals.
5. Arrange for helicopter services to transport the injured to national hospitals outside the area as soon as possible.
6. Take or send specialists to repair the electricity, water and sewage services as soon as possible.
7. Repair all communication services as soon as possible.
8. Clear all debris and stray objects to prevent further injuries.

2. PRECAUTIONARY MEASURES

1. Promptly leave all low-lying areas.

2. Everybody should take care that their cars are filled up with fuel. Also check the battery, water, oil and tyres. If the need arises, evacuation can take place smoothly.

3. Conserve water for drinking purposes.

4. Stock up non-perishable foodstuffs.

5. Have a flashlight, first aid kit, fire extinguisher and battery radio at hand.

6. Stack all loose objects away or tie bigger items to sturdy pillars.

7. Secure all windows with nails and board

8. Listen to the radio and watch TV for information from the weather bureau.