Cyclone Shakhti forms over Arabian Sea

Why in the News?

The India Meteorological Department (IMD) confirmed the formation of Cyclone Shakthi (named by Sri Lanka) over the northeast Arabian Sea.

About Cyclogenesis in the Arabian Sea:

• Overview: Cyclogenesis is the formation and intensification of tropical cyclones under favourable oceanic and atmospheric conditions.
• Seasonality: Most active during pre-monsoon (Apr–Jun) and post-monsoon (Oct–Dec) periods, when sea surface temperatures (SSTs) exceed 27 °C, moist convection intensifies, and the Coriolis effect induces rotation.
• Formation Process: Warm moist air rises forming low pressure; latent heat of condensation deepens the system; upper-level outflow and low vertical wind shear sustain vertical growth, producing a warm eye with spiral rainbands.
• Historical Pattern: The Arabian Sea was once less cyclone-prone than the Bay of Bengal due to cooler waters, dry winds, and high wind shear. Limited basin size and monsoon winds restricted cyclone growth.
• Recent Change: Ocean warming and climate change have sharply increased cyclonic activity, making the region far more active in the last decade.
• Rapid Intensification Trend: Short-term surges in wind speed (< 24 hrs) are now common, linked to warmer SSTs, Indian Ocean Dipole (IOD) shifts, and monsoon wind variability.
• Oceanic–Climatic Drivers:
  • Indonesian Throughflow imports warm Pacific waters, raising SSTs.
  • Southern Ocean inflow brings cooler deep water, stabilising lower layers.
  • Dual cyclone seasons arise from monsoon wind reversal unique to the region.
• Climate Change Impact:
  • IMD data show a 52 % rise in Arabian Sea cyclones in two decades, while Bay of Bengal activity slightly declined.
  • The Indian Ocean is among the fastest-warming oceans, increasing heat-moisture availability, altering global weather, and heightening coastal risks to life and infrastructure.

Recent Examples:

• Tauktae (2021) – winds > 185 km/h, heavy damage along Gujarat–Konkan.
• Biparjoy (2023) – lasted 13 days, fed by SSTs ~31 °C.
• Tej (2023) – hit Oman & Yemen, showing cross-basin movement.
• Shakthi (2025) – latest late-season, fast-intensifying cyclone.