Tropical Cyclone Idai has caused huge deaths and economic losses in Mozambique, Malawi, Zimbabwe, and South Africa. Cyclone Idai made landfall on Mozambique and later moved in a westerly direction. Idai is the deadliest Tropical cyclone witnessed in 2019.
Idai originated from a tropical depression that formed off the eastern coast of Mozambique and made landfall in Mozambique. The depression later reemerged into the Mozambique Channel and was upgraded into Moderate Tropical Storm.
Tropical Cyclone is an intense low-pressure area or a whirl in the atmosphere over tropical or sub-tropical waters, with organised convection, circulating either anti-clockwise (in the northern hemisphere) or clockwise (in the southern hemisphere).
Conditions which favour Tropical Cyclone Formation
- A source of warm, moist air derived from tropical oceans with sea surface temperature normally near to or in excess of 27 °C
- Winds near the ocean surface blowing from different directions converging and causing air to rise and storm clouds to form
- Winds which do not vary greatly with height known as low wind shear. This allows the storm clouds to rise vertically to high levels.
- Coriolis force/spin induced by the rotation of the Earth. The formation mechanisms vary across the world, but once a cluster of storm clouds starts to rotate, it becomes a tropical depression. If it continues to develop it becomes a tropical storm, and later a cyclone/ super cyclone.
Pressure increases outwards from the centre of a cyclonic storm. The amount of the pressure drop in the centre and the rate at which it increases outwards gives the intensity of the cyclones and the strength of winds.