Cyclone Michaung

Why in news?

Recently the Cyclone Michaung made landfall over Nellore in Andhra Pradesh as a super-cyclonic storm.

How the Cyclone Michaung formed?

• Origin- The cyclone developed from a low pressure area in the southwest Bay of Bengal. It gradually intensified into a deep depression, a cyclonic storm, and finally a super-cyclonic storm.
• Intensification- They were aided by warm sea surface temperatures and the Madden-Julian oscillation, a weather anomaly that influences rainfall patterns.
• Course of action- It moved northward towards the Andhra Pradesh coast, while bringing heavy rain and strong winds to north Tamil Nadu. It made landfall near Bapatla district, and weakened into a depression over land.
• Naming convention-The name Michaung was suggested by Myanmar symbolises strength and resilience following the list of names prepared by World Metrological Organisation and the United Nations Economic and Social Commission for the Bay of Bengal and the Arabian Sea.
• The name of each cyclone is picked from this list and cycles through each country's suggestion.
• Super-cyclonic storm- It was the 4^th tropical cyclone of the year over the Bay of Bengal, and the first super-cyclonic storm since 1999. It reached a peak intensity of 90-100 km/hr winds gusting to 110 km/hr at the time of landfall.

Why did the Cyclone intensify?

Cyclogenesis, is the development or strengthening of cyclonic circulation in the atmosphere

• Cyclone intensification events- They are a source of uncertainty in cyclone models because they alter the storm’s future course. They depend on several factors, such as sea surface temperature, vertical wind shear, upper-level divergence, etc.,
• Global warming- It has already resulted in a detectable increase in the number of higher intensity cyclones as well as their intensification.
• Climate change- It has increased the sea surface temperature, which is conducive to cyclone intensification. A study found that tropical cyclones with wind speeds above 185 km/hr had become 15% more likely since 1979.
• Cyclone engine-Cyclones are like engines that convert the heat and moisture from the ocean into kinetic energy of winds.
• The rising air cools and condenses, forming clouds and releasing latent heat, which makes the air lighter and causes it to rise further. The surrounding air moves in to fill the low pressure, creating surface winds.
• Madden-Julian oscillation- It throw seeds of rotational low-pressure systems over the Indian and the Pacific Oceans, this indicated favourable conditions for the cyclone.
• Rapid intensification- It is defined as an increase in maximum sustained winds by at least 55 kilometre / hour in a 24-hour period.
• Unpredictable- The cyclone spent more time over the water before landfall, as Cyclone Michaung did off the coast of north Tamil Nadu.

What is the consequences of the intensification?

• Complicated forecast models-Due to rapid intensification, the cyclone deviated from its expected track and speed increased the uncertainty and complexity of cyclone preparedness.
• Prolonged rains- It allows storms to make landfall with more energy, move further inland, survive longer, and extend their on-ground devastation to previously ‘inaccessible’ areas.
• Heavy damage- It brought heavy rain and winds with a sustained speed of 90-100 km/hr, in the process uprooting trees and electric poles. It caused heavy to extremely heavy rain in several parts of Andhra Pradesh, Tamil Nadu and southern Odisha.
• Stronger winds -The wind speed of a cyclone is related to its central pressure, the lower the pressure, the stronger the wind.
• Cyclone Michaung reached a peak intensity of 90-100 km/hr winds gusting to 110 km/hr at the time of landfall.
• Higher storm surge- The cyclone generated storm surge and tidal waves up to 1.5 metres, along with flash floods in low lying areas.
• Human impact- It affected around 40 lakh people, many people stranded in flood without access to basic amenities like food, water etc.,
• Economic impact-It resulted in widespread damage to infrastructure, crops and livelihoods.

References

1. The Hindu- How Cyclone Michayung formed
2. Indian Express- Unusual storm