A tropical cyclone is a non-frontal intense low-pressure weather system. They are often known by many names around the world; hurricanes, typhoons, cyclones, and storms. Between 2001 and 2010 500 tropical storms killed over 170,000 people. These storms develop over tropical and subtropical oceans between the tropic of Cancer and Capricorn. They form over water that is above 27 degrees Celsius, usually towards the end of summer and in the autumn. The movement of the ITCZ controls the location of the storms. Tropical storms do not form along the equator because the Coriolis effect is not strong enough to make storms spin.
Tropical storm formation follows a particular sequence: Air is heated above the surface of warm tropical oceans. The warm air rises rapidly under low pressure conditions. The rising air draws up more air and water vapour, causing strong winds. The Coriolis effects causes the air mass to spin around the eye of the storm. As the air rises, it cools and condenses to form large clouds and heavy rainfall. The heat given off powers the storm. Cold air sinks in the eye of the storm, creating calmer conditions. Prevailing winds move the storm across the ocean. The storm begins to weaken on land as it has lost its source of moisture.
With rising temperatures and sea levels, storm surges are expected to become higher. Warmer air masses can hold more moisture. This will increase rainfall, making storms more destructive. Storms are expected to become 2-11% more intense by 2100. It is estimated that every degree of warming will increase wind speeds by 3-5% The overall number of storms is expected to stay the same or even decrease in the future. However, the number of severe storms will increase.
Tropical storms bring strong winds, torrential rainfall, and storm surges (rapid sea level rise). Flooding is a major impact of these storms, often causing the most deaths. Tropical storms can also cause landslides and tornadoes. Wind speeds can rise up to 119km/hour. This is strong enough to demolish houses, destroy infrastructure, and wipe out crops. Water supplies are often contaminated, causing disease and deaths. The amount of destruction in a storm depends on the protection available and the response of the affected areas. Aid is often difficult due to damaged roads and restricted access. It can take much longer for aid to reach remote areas. Storms are measured using the Saffir-Simpson hurricane wind scale. As storms can be predicted, warnings and evacuations often take place. High Income Countries (HICs) are more likely to be able to prepare for storms than poorer countries, often having shelter ready for residents.
Monitoring: Monitoring tropical storms allows predictions to be made, which can reduce damage through increased preparation. The Global Precipitation Measurement was launched in 2004 to monitor precipitation in tropical regions. NASA Global Hawk Drones monitor tropical storms to improve forecasting models. Prediction: New supercomputers can now give 5 days warning for storms and can give an accurate location within 400km. National Hurricane Centers can predict a storm's path relatively accurately and determine the behaviour of the storm before it hits land. Planning: Homeowners in vulnerable areas are urged to install hurricane straps between the roof and walls, install storm shutters on windows, install an emergency generator, and remove trees close to buildings to protect their homes. Trees can reduce wind energy and trap debris that would cause damage, but can also cause damage if uprooted. Coastal flooding defences such as levees and flood walls can be put in place. Individual planning of disaster supply kits and evacuation schemes can aid protection.