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Heavy monsoon downpours across Uttarakhand, Himachal Pradesh and Jammu and Kashmir have caused repeated flash floods and landslides, bringing renewed attention to cloudbursts.
The India Meteorological Department defines a cloudburst as 100 mm or more of rainfall in one hour over an area of roughly 20 to 30 square kilometres.
Cloudbursts are concentrated in the Himalayan belt because steep orographic slopes force moist air to rise rapidly.
The volume of water falling far exceeds the ground's absorption capacity, producing sudden and destructive flash floods.
The highest-risk zones are Uttarakhand, Himachal Pradesh, Jammu and Kashmir, Ladakh, the Northeast states and the Western Ghats.
A cloudburst is a highly localised, extremely intense rainfall event. The India Meteorological Department defines it as 100 mm or more of rain falling within one hour over an area of about 20 to 30 square kilometres. The mechanism is a towering cumulonimbus cloud in which strong updrafts hold raindrops suspended instead of letting them fall. As the drops keep growing, the moisture load eventually exceeds what the updraft can support, and the entire accumulated volume descends almost at once rather than over hours. The result is not merely heavy rain but a sudden release of water far beyond what the ground can absorb.
Simple Analogy: It is the difference between a tap running steadily into a bucket and a full bucket being tipped over in one go — the same volume of water, but the second causes damage the first never would.
[["Nature","Extreme rain concentrated in about an hour","Heavy rain measured over 24 hours","Persistent high-pressure system trapping hot air"],["Spatial extent","Highly localised, about 20-30 sq km","Can cover large regions","Covers a very large area"],["Main hazard","Flash floods, landslides, debris flows","River flooding and waterlogging","Prolonged extreme heat"],["Predictability","Very difficult to forecast at local scale","Reasonably forecastable","Forecastable days in advance"]]
["Aspect","Cloudburst","Very heavy rainfall (IMD category)","Heat dome"]
GS Paper 1 > Important Geophysical Phenomena; GS Paper 3 > Disaster and Disaster Management
General Awareness > Geography and Environment
With reference to 'Indian Ocean Dipole (IOD)' sometimes mentioned in the news while forecasting Indian monsoon, which of the following statements is/are correct? 1. IOD phenomenon is characterised by a difference in sea surface temperature between tropical Western Indian Ocean and tropical Eastern Pacific Ocean. 2. An IOD phenomenon can influence an El Nino's impact on the monsoon. Select the correct answer using the code given below:
Answer: 2 only
Which river is known as the 'Sorrow of Bihar'?
Answer: Kosi
Rainfall of 100 mm or more within one hour over an area of roughly 20 to 30 square kilometres, as defined by the IMD.
The forced upward movement of air when it encounters rising terrain, cooling it and causing condensation.
A sudden, rapid-onset flood caused by intense rainfall over a short period, typically in steep terrain.
A fast-moving mixture of water, soil and rock that carries far greater destructive force than water alone.
A towering convective cloud with powerful updrafts, associated with thunderstorms and cloudbursts.