Typhoon Ragasa

Why in News?

Super Typhoon Ragasa strike Hong Kong with fierce winds and pounding rain, and headed into southern China recently.

• It is the most intense tropical cyclone recorded in 2025. At its peak, Ragasa was moving with the maximum sustained winds of 280 kmph.
• Ragasa has been referred to as a super typhoon because it is a Category 5 tropical cyclone.
• Formation - Ragasa originated from a tropical depression and rapidly intensified into a super typhoon.
• Causes – It causes death and widespread damage across the Philippines, Taiwan, Hong Kong, and southern China.
• In Philippines - The storm first made landfall in the northern Philippines, causing heavy rain, landslides.
• In Taiwan - As the typhoon passed, a barrier lake burst its banks in Hualien County, releasing a "tsunami from the mountains".

A barrier lake, or landslide-dammed lake, forms when natural material like rocks, dirt, or debris from landslides block a river or valley.

• In Hong Kong - Ragasa skirted Hong Kong, bringing the city to a standstill with powerful winds, heavy rain, and storm surges.
• In Southern China - Ragasa made its final landfall in Yangjiang, Guangdong province.

Formation of Tropical cyclones

• Tropical cyclones form over warm ocean waters near the equator.
• When the warm, moist air from the ocean surface rises upward, a lower air pressure area is formed below.
• Air from surrounding areas with higher air pressure rushes into this low-pressure area, eventually rising, and it becomes warm and moist.
• As warm, moist air rises, it cools down, and the water in the air forms clouds and thunderstorms.
• This whole system of clouds and winds gains strength and momentum using the ocean’s heat, and the water that evaporates from its surface.
• Classification - The weakest tropical cyclones are called tropical depressions.
• If a depression intensifies such that its maximum sustained winds reach 39 miles per hour [63 kmph], the tropical cyclone becomes a tropical storm.
• Storm systems with wind speeds of 119 kmph and above are classified as hurricanes, typhoons, or tropical cyclones.
• The category of a tropical cyclone is determined by its sustained wind speed, as measured by the Saffir-Simpson Hurricane Wind Scale.
• It is classified into 5 categories - Category 1 to Category 5.

Reference

The Indian Express | Super Typhoon Ragasa