Context

Bulbul damages crops, houses, electricity and water connections in Odisha and West Bengal

About

• Very Severe Cyclonic Storm Bulbul is an active tropical cyclone which struck the Indian state of West Bengal.
• At Category 2 hurricane-equivalent intensity and is currently a flood and storm surge threat to Bangladesh.
• Originating from the remnants of Severe Tropical Storm Matmo over the southern Bay of Bengal.
• It is only the fourth tropical cyclone ever recorded to regenerate over the Andaman Sea, having crossed Southeast Asia overland.
• The cyclone has been named by Pakistan.

Tropical cyclones

• Tropical cyclone, also called typhoon or hurricane, an intense circular storm that originates over warm tropical oceans and is characterized by low atmospheric pressure, high winds, and heavy rain.
• Drawing energy from the sea surface and maintaining its strength as long as it remains over warm water, a tropical cyclone generates winds that exceed 119 km per hour.
• Tropical cyclones are known by various names in different parts of the world. In the North Atlantic Ocean and the eastern North Pacific they are called hurricanes, and in the western North Pacific around the Philippines, Japan, and China the storms are referred to as typhoons. In the western South Pacific and Indian Ocean they are variously referred to as severe tropical cyclones, tropical cyclones, or simply cyclones.
• A characteristic feature of tropical cyclones is the eye, a central region of clear skies, warm temperatures, and low atmospheric pressure.

The conditions for the formation of Tropical cyclones

• The temperature of the surface layer of ocean water must be 26.5 °C or warmer, and this warm layer must be at least 50 metres deep.
• A pre-existing atmospheric circulation must be located near the surface warm layer.
• The atmosphere must cool quickly enough with height to support the formation of deep convective clouds.
• The middle atmosphere must be relatively humid at a height of about 5,000 metres above the surface.
• The developing system must be at least 500 km away from the Equator.