Cyclone & Flood Management — Set 5

Correct Answer: C. 100 years

The 2018 Kerala floods were described as the worst flooding in Kerala in nearly 100 years, since the great flood of 1924. The floods were caused by exceptionally heavy monsoon rainfall in August 2018, affecting all 14 districts of Kerala. Over 400 people were killed and more than one million people were displaced from their homes.

Correct Answer: D. All 14 districts

All 14 districts of Kerala were affected by the devastating floods of August 2018. The floods were caused by unusually high rainfall during the southwest monsoon season, combined with heavy releases from over 35 dams across the state. The disaster killed over 400 people, displaced more than a million, and caused damages estimated at over ₹40,000 crore.

Correct Answer: B. Cloudburst — 944 mm rainfall in one day

The Mumbai floods of 2005 were triggered by a historic cloudburst on July 26, 2005, when Mumbai recorded 944 mm of rainfall in a single day, the highest ever recorded in India at the time. The extreme rainfall overwhelmed Mumbai's drainage system, causing severe flooding across the city. Over 1,000 people died and the city was paralysed for several days.

Correct Answer: C. 2015

Chennai experienced severe urban flooding in December 2015, when the northeast monsoon brought unprecedented rainfall to Tamil Nadu. The Chembarambakkam reservoir was opened during peak rainfall, contributing to flooding in many parts of Chennai. Over 500 people died, thousands were evacuated, and the city faced a total shutdown for several days.

Correct Answer: B. Abnormal rise of sea water due to cyclonic winds

A storm surge is an abnormal rise of sea water level caused by the strong winds and low pressure associated with a cyclone pushing water towards the coast. Storm surges are often the deadliest component of a cyclone, capable of inundating vast coastal areas many kilometres inland. The 1999 Odisha cyclone's storm surge of up to 9 metres was largely responsible for the massive death toll.

Correct Answer: B. Calm, clear skies, and low winds

The eye of a cyclone is the calm, clear centre of the storm characterized by low wind speeds, no rain, and often clear skies. It is surrounded by the eyewall, which contains the most intense rainfall and strongest winds. The eye typically ranges from 20 to 65 km in diameter and appears as a dark spot on satellite imagery.

Correct Answer: B. East coast

India's east coast is significantly more vulnerable to cyclones than the west coast because the Bay of Bengal generates far more cyclones than the Arabian Sea. The east coast states of West Bengal, Odisha, Andhra Pradesh, and Tamil Nadu bear the brunt of most cyclone landfalls. The Bay of Bengal's warm waters and geography make it one of the most active cyclone basins globally.

Correct Answer: C. October–December

October–December is the peak period for cyclones in the Bay of Bengal, coinciding with the post-monsoon season. A secondary peak also occurs during the pre-monsoon period of April–June. During the southwest monsoon months of July–August, cyclone activity is relatively suppressed despite warm sea temperatures.

Correct Answer: C. 63 km/h

A weather system must have sustained wind speeds of at least 63 km/h to be classified as a Cyclonic Storm by IMD. Below this threshold, systems are classified as Deep Depression (50–62 km/h) or Depression (31–49 km/h). The seven-tier IMD classification system helps authorities plan evacuation and disaster response proportionate to the threat.

Correct Answer: B. Severe Cyclonic Storm

A Severe Cyclonic Storm in IMD's classification has sustained wind speeds of 89–117 km/h. This is the fourth tier in the seven-tier IMD classification scale. At this intensity, the cyclone can cause significant damage to structures, trees, and crops, and poses serious danger to fishermen and coastal communities.