In recent years, India has faced a sharp rise in cloudburst events, especially in the Himalayan and hill regions. These incidents often result in flash floods, landslides, and urban flooding, causing serious damage to life and infrastructure.
But what exactly is a cloudburst? And why does it happen so frequently in places that aren’t even very hot, like the mountains of Uttarakhand, Himachal Pradesh, Ladakh, and Sikkim?
Let’s break it down through geography.
Contents
What is a Cloudburst? (IMD Definition)
According to the India Meteorological Department (IMD), a cloudburst is defined as:
Rainfall of more than 100 mm within one hour over a very small area (about 20–30 sq km).
It feels like the cloud has “burst” open and released all its water at once.
This is different from “extremely heavy rainfall,” which is measured over a 24-hour period.
IMD Classification of Rainfall (24 hours):
- Heavy rainfall: 115.6 mm – 204.4 mm
- Extremely heavy rainfall: Above 204.4 mm
👉 Cloudburst = 100 mm or more in ONE hour
👉 Extremely heavy rainfall = 204 mm in 24 hours
Both are dangerous, but they are not the same. This differentiation is very important for UPSC prelims and mains.
Why Do Cloudbursts Happen More in the Himalayas?
This is the most important geography concept.
Normally, we assume:
- More heat → stronger convection → heavy rainfall
- Mountains are cooler → less convection
So why more cloudbursts in mountains?
The answer lies in orographic uplift + global warming + moist monsoon winds.
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1. Orographic Uplift (Mountain Barrier Effect)
During the South-West Monsoon, moisture-laden winds from:
- Arabian Sea
- Bay of Bengal
travel towards North India. When these winds hit the Himalayan mountains, they are forced to rise upward suddenly.
As they rise:
- Temperature drops
- Water vapour condenses
- Heavy rain occurs over a very small area
This forced uplift leads to intense, concentrated rainfall → cloudburst.
2. Global Warming and Mountain Heating
Even though mountains are cooler than plains, climate change has warmed them too. Warmer air holds more moisture, which increases the intensity of rainfall events.
So now we have:
- More moisture in the air
- Faster rising air currents
- Greater instability in the atmosphere
Perfect conditions for cloudbursts.
Where Are Cloudbursts Most Common in India?
Cloudbursts are most frequent in:
- Uttarakhand
- Himachal Pradesh
- Jammu & Kashmir
- Ladakh
- Sikkim
- Parts of North-East India
These are all mountainous or hilly regions, confirming the strong link with orographic uplift.
They cause:
- Flash floods
- River overflow
- Landslides
- Destruction of villages and roads
Why Cloudbursts are Important for UPSC
Cloudbursts connect multiple GS themes:
GS Paper 1 (Geography)
- Monsoon winds
- Orographic rainfall
- Himalayan geography
- Extreme weather events
GS Paper 3 (Environment & Disaster Management)
- Climate change impact
- Natural disasters
- Urban flooding
- Himalayan vulnerability
This makes it a high-probability topic for Prelims, Mains & Essay.
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FAQs
- #CloudburstInIndia – What is a cloudburst and how does the IMD define?
- #IMDRainfallClassification – How is a cloudburst different from extremely heavy rainfall?
- #HimalayanCloudburst – Why are cloudbursts more common in Himalayan and hilly regions of India?
- #OrographicRainfallUPSC – How does orographic uplift contribute to cloudbursts during the monsoon?
