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Cyclones

Cyclones

Wind plus heat: The triggers for deadly UP storm

Why in the News?

More than 100 deaths in Uttar Pradesh due to pre-monsoon thunderstorms have brought renewed attention to India’s growing vulnerability to compound weather events. In such events, multiple meteorological factors combine to intensify disasters. The event stood out because of its unusual intensity, wider geographic spread, and exceptionally high wind speeds. Several districts recorded winds above 100 kmph and touching 130 kmph, far exceeding normal pre-monsoon conditions.

Why did the Uttar Pradesh thunderstorm become unusually deadly this year?

  1. Higher Fatality Burden: More than 100 deaths were reported, making it one of the deadliest thunderstorm events in recent years in northern India.
  2. Geographical Spread: The destruction was more widespread than usual, affecting multiple districts rather than isolated pockets.
  3. Extreme Wind Speeds: At least eight districts recorded wind speeds exceeding 100 kmph. Some locations witnessed gusts of nearly 130 kmph, substantially above the normal 40-60 kmph range associated with pre-monsoon storms.
  4. Infrastructure Vulnerability: Walls collapsed, electricity poles were uprooted, hoardings fell, and loose objects became projectiles, increasing casualties and injuries.
  5. Lightning Risk: Lightning strikes contributed to deaths, consistent with India’s recurring vulnerability to thunderstorm-associated lightning fatalities.

How do pre-monsoon thunderstorms normally develop over northern India?

  1. Seasonality: Pre-monsoon thunderstorms are common during April and May, sometimes extending into July, particularly in northern India.
  2. Surface Heating: Intense land heating raises surface temperatures, creating unstable atmospheric conditions conducive to thunderstorm formation.
  3. Moisture Inflow: Moist southeasterly winds from the Bay of Bengal transport humidity inland, providing the moisture required for cloud formation.
  4. Atmospheric Instability: Warm moist air near the surface rises rapidly, generating cumulonimbus clouds associated with thunder, lightning, rainfall, hail, and gusty winds.
  5. Global Occurrence: Such storms are not unique to India and frequently occur in arid and semi-arid regions globally.

What meteorological conditions intensified the storm beyond normal levels?

  1. Extreme Heat Conditions: Temperatures crossing 45°C across several regions increased surface heating and strengthened convective activity.
  2. Strong Southeasterly Winds: Persistent moisture transport from the Bay of Bengal extended unusually far inland, reportedly reaching even northwestern Uttar Pradesh.
  3. Western Disturbances: Rain-bearing systems originating beyond Iran introduced cool, dry air in the upper atmosphere, creating a sharp contrast with the warm, moist lower atmosphere.
  4. Thermal Contrast: Cool upper air interacting with hot lower air created severe instability, a classic condition for powerful thunderstorms.
  5. Compound Interaction: The storm emerged not from one factor but from the coincidence of multiple meteorological triggers operating simultaneously.

Why are strong winds during thunderstorms particularly destructive in northern India?

  1. Wind Intensity: Normal thunderstorm winds range between 40-60 kmph, but speeds above 90 kmph are sufficient to uproot trees and damage structures.
  2. Urban Exposure: Billboards, electricity poles, weak infrastructure, and informal settlements increase disaster exposure.
  3. Flying Debris: Loose construction materials and roadside objects transform into dangerous projectiles during high-speed winds.
  4. Agricultural Losses: Standing crops, orchards, and rural infrastructure remain vulnerable during pre-monsoon storm episodes.
  5. High Population Density: The densely populated Gangetic plain amplifies human and economic losses from weather extreme.

Why was forecasting unable to fully anticipate the scale of destruction?

  1. Forecast Availability: The India Meteorological Department (IMD) had already issued weather bulletins and warnings regarding thunderstorms.
  2. Underestimation of Wind Speed: Initial IMD forecasts predicted winds of up to 60 kmph, later revised to 70 kmph.
  3. Real-Time Escalation: Nowcast systems later indicated potential winds of 80-90 kmph, yet several districts experienced speeds exceeding 100 kmph.
  4. Forecasting Complexity: Thunderstorms are highly localised and dynamic phenomena, making precise prediction of intensity difficult.
  5. Evacuation Constraints: Unlike cyclones, thunderstorms lack a clear directional pathway, limiting targeted evacuation measures.

How does this event compare with earlier extreme thunderstorm episodes?

  1. Historical Similarity: The meteorological pattern resembled 2018, when a similar thunderstorm event caused over 100 deaths in northern India.
  2. Recurring Hazard: Northern India experiences dozens of deaths annually from thunderstorms of varying intensity.
  3. Changing Risk Profile: Recent events indicate increasing concern regarding high-intensity short-duration weather extremes, potentially linked to broader climate variability.

What governance and disaster-management lessons emerge from the Uttar Pradesh storm?

  1. Forecast Modernisation: Strengthens the need for high-resolution local forecasting systems and improved nowcasting capacity.
  2. Infrastructure Resilience: Ensures storm-resistant electricity networks, urban signage regulation, and structural safety standards.
  3. Early Warning Dissemination: Facilitates last-mile communication through SMS alerts, local administration, and community networks.
  4. Lightning Preparedness: Supports expansion of lightning detection systems and public advisories, especially in rural regions.
  5. Climate Adaptation: Reinforces the need for district-level climate-risk planning for compound extreme events.

Conclusion

The Uttar Pradesh thunderstorm demonstrates how heat stress, moisture transport, and upper-atmospheric disturbances can combine to produce severe local disasters. The event highlights the limits of conventional forecasting and reinforces the need for hyperlocal warning systems, resilient infrastructure, and climate-adaptive disaster planning. This has to be done to manage increasingly volatile pre-monsoon weather.

PYQ Relevance

[UPSC 2024] What is the phenomenon of ‘cloudbursts’? Explain

Linkage: The PYQ tests conceptual understanding of extreme atmospheric phenomena, weather instability, and disaster geography. Both thunderstorms and cloudbursts involve intense atmospheric instability caused by heat, moisture, and upper-air interactions.

May 16 2026

Cyclones

Cyclone Montha makes landfall in AP

Why in the News?

Cyclone Montha, classified as a severe cyclonic storm, has made landfall near Kakinada (Andhra Pradesh) on October 28.

Back2Basics: Tropical Cyclones

  • What is it: Large low-pressure systems over warm oceans, marked by rotating winds, heavy rain, and storm surges.
  • Conditions: Form when ocean temps >27°C, with moist rising air releasing latent heat to fuel convection.
  • Rotation: Driven by the Coriolis force – anticlockwise in Northern Hemisphere, clockwise in Southern.
  • Structure: Eye (calm), Eyewall (violent winds/rains), Rainbands (widespread showers).
  • Regional Names: Typhoons (Pacific), Hurricanes (Atlantic/Caribbean), Cyclones (Indian Ocean).
  • Drivers & Frequency: Common in Southeast Asia due to warm Pacific waters, El Niño/La Niña cycles, and climate change.
  • Impacts: Loss of life, property damage, flooding, soil salinisation, displacement, and disease outbreaks.
  • Climate Change Link: Global warming is making tropical cyclones stronger, less predictable, and more frequent, raising risks for coastal populations.

What is the Landfall of a Cyclone?

  • Overview: A tropical cyclone is said to make landfall when its centre (eye) crosses the coastline from sea to land.
  • Not the Same as a Direct Hit:
    • Landfall = when the eye crosses the coast.
    • Direct hit = when the eyewall (zone of strongest winds) impacts the coast, even if the centre remains offshore.
  • Duration: Landfall usually lasts a few hours, depending on wind speed and storm size.
  • Post-Landfall Behaviour: Cyclones lose intensity rapidly after landfall due to loss of oceanic moisture and increased land friction.

Behind the Naming of Cyclones:

  • Overview: Cyclones in the North Indian Ocean are named under the World Meteorological Organization (WMO) / United Nations Economic and Social Commission for Asia and the Pacific (ESCAP) Panel on Tropical Cyclones (since 2004).
  • Naming Authority: Regional Specialized Meteorological Centre (RSMC), New Delhi, operated by IMD.
  • 13 Member Countries: Bangladesh, India, Maldives, Myanmar, Oman, Pakistan, Sri Lanka, Thailand, Yemen, Iran, Qatar, Saudi Arabia, and UAE.
  • Submission of names: Each country submits 13 culturally neutral, gender-neutral names, forming a 169-name rotating list.
  • Non-repetition: Names are used sequentially and not repeated after one use.
  • “Montha”: It was suggested by Thailand, meaning “beautiful” or “fragrant flower.”
  • Significance: Naming helps public communication, ensures clarity in warnings, and avoids confusion during multiple simultaneous storms.
  • Current sequence: Shakthi (Sri Lanka) → Montha (Thailand) → Senyar (UAE) → Ditwah (Yemen) → Arnab (Bangladesh) → Murasu (India).
[UPSC 2020] Consider the following statements:

1. Jet streams occur in the Northern Hemisphere only.

2. Only some cyclones develop an eye.

3. The temperature inside the eye of a cyclone is nearly 10°C lesser than that of the surroundings.

Which of the statements given above is/are correct?

(a) 1 only (b) 2 and 3 only (c) 2 only* (d) 1 and 3 only

 

October 29 2025

Cyclones

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.

Back2Basics: Tropical Cyclones

  • What is it: Large low-pressure systems over warm oceans, marked by rotating winds, heavy rain, and storm surges.
  • Conditions: Form when ocean temps >27°C, with moist rising air releasing latent heat to fuel convection.
  • Rotation: Driven by the Coriolis force – anticlockwise in Northern Hemisphere, clockwise in Southern.
  • Structure: Eye (calm), Eyewall (violent winds/rains), Rainbands (widespread showers).
  • Regional Names: Typhoons (Pacific), Hurricanes (Atlantic/Caribbean), Cyclones (Indian Ocean).
  • Drivers & Frequency: Common in Southeast Asia due to warm Pacific waters, El Niño/La Niña cycles, and climate change.
  • Impacts: Loss of life, property damage, flooding, soil salinisation, displacement, and disease outbreaks.
  • Climate Change Link: Global warming is making tropical cyclones stronger, less predictable, and more frequent, raising risks for coastal populations.

 

[UPSC 2020] Consider the following statements:

1. Jet streams occur in the Northern Hemisphere only.

2. Only some cyclones develop an eye.

3. The temperature inside the eye of a cyclone is nearly 10°C lesser than that of the surroundings.

Which of the statements given above is/are correct?

(a) 1 only (b) 2 and 3 only (c) 2 only* (d) 1 and 3 only

 

October 6 2025

Cyclones

On uncommon cyclones in the Arabian Sea

Note4Students

From UPSC perspective, the following things are important:

Prelims level: Tropical and temperate cyclone;

Mains level: Impact of climate change on cyclone;

Why in the News?

A rare August cyclone, named ‘Asna’, currently positioned off the Kutch coast is even more remarkable for having originated over land.

Why was there a lot of excitement over Asna?

  • “Asna” is notable because it’s the first cyclone in August in the North Indian Ocean since 1981. August is typically not part of the cyclone season in this region.
  • The cyclone began as a land-born depression that intensified as it moved over the warm waters of the Arabian Sea. It formed from a rare strong low-pressure system that grew unusually powerful over land.
  • Asna’s formation is linked to the broader context of rapid warming over the Arabian Sea, influenced by climate change. The northward shift of the low-level jet stream due to warming over West Asia contributed to its development.

Why does the North Indian Ocean have two cyclone seasons?

The North Indian Ocean has two distinct cyclone seasons due to the unique monsoonal circulation patterns in the region:

  • Pre-monsoon season (March-May): The Arabian Sea warms rapidly during this time as the sun crosses over to the Northern Hemisphere. The Bay of Bengal is relatively warmer and begins producing atmospheric convection and rainfall. This leads to cyclogenesis in both the Arabian Sea and the Bay of Bengal.
  • Post-monsoon season (October-December): This is the northeast monsoon season for India. The Arabian Sea cools due to the strong southwesterly winds and mixing of cold subsurface waters. However, the Bay of Bengal remains favourable for cyclogenesis. The post-monsoon season is the major cyclone season in the North Indian Ocean

How is climate change affecting the region?

  • Warming of the Indian Ocean: Climate change is amplifying the warming of the Indian Ocean, with more heat being transferred from the Pacific Ocean and Southern Ocean. This increases the overall sea surface temperature (SST), crucial for cyclone formation.
  • Monsoon and cyclones: The warming affects the monsoon patterns and has the potential to change cyclone intensity. More heat and moisture from the warming seas lead to more energy available for cyclones.
  • Impact on global ocean circulation: The warming of the Indian Ocean is also affecting global ocean currents, impacting heat uptake by the Pacific Ocean and water sinking in the North Atlantic. The Indian Ocean is playing a central role in global climate change processes.

Way forward: 

  • Strengthening Early Warning Systems: Enhance real-time monitoring and forecasting of cyclones, particularly in the pre- and post-monsoon seasons, using satellite data and advanced models.
  • Building Climate Resilience: Implement climate adaptation strategies, especially for coastal communities, by improving infrastructure and disaster preparedness to cope with increasing cyclone intensity due to climate change.

Mains PYQ:

Q Discuss the meaning of colour-coded weather warnings for cyclone prone areas given by India Meteorological Department. (UPSC IAS/2022)

 

September 9 2024

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