Cloudbursts - About, Impact and Prevention

Cloudbursts are sudden, unprecedented heavy rainfall that is local in nature and abrupt in action. Rainfall over 100 mm or 10 cm per hour over a region of 20 to 30 square km falls into this category.

This topic has a high probability of being asked as a UPSC Prelims Geography question. This topic is also relevant from the perspective of the mains for GS-2 and GS-3 papers.

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What is Cloudburst?

Cloudburst is defined as a geo-hydrological hazard. The aggressiveness in nature and the scale of destruction of rainfall are scary at times. In India, cloudburst occurs during the time of the South-West Monsoon from the month of June. Cloudburst is difficult to predict since it occurs suddenly with a catastrophic force and thereby inflicts enormous losses due to inundation and erosion.

How do they occur?

It occurs mainly in mountainous areas when the warm air currents rise from the ground towards clouds. It carries the falling raindrops along with it. Thus, the rainfall fails to occur steadily, and the clouds have excessive condensation. There is also an accumulation of a large amount of water at high altitudes. The warm air from below restricts the fall of water. The upward current becomes weak, and the waterfalls on a single stretch. The requisite energy for the downpour comes from the movement of air upwards. Generally, cloudbursts occur at an elevation of 1000 to 2500 meters above sea level. Cumulonimbus clouds are responsible for the heavy downpour. In cloudbursts, smaller droplets of water coagulate with smaller ones and result in the Langmuir precipitation process (the process in which large droplets of rain coagulate with tiny droplets of rain, which fall down slowly.)

Read about different types of clouds from the following link: Types of Clouds

Why is cloudburst referred to as a hazard?

The impact of a cloudburst depends on the scale of destruction it causes to the people and property. It is indeed difficult to predict the cloudburst with accuracy.

After Effects of Cloudbursts

• Continuous and violent rainfall can result in heavy floods that can be dangerous. 
• It also causes-
  • Debris flows
  • Landslides
  • Mudslides
  • Flooding
  • Mass Movements
  • Drownings
  • Road closures and cloudburst
  • Accidents

• Cloudbursts in hilly terrains can be disastrous and cause massive destruction to life and property as most of the water gets concentrated in the valleys and gullies.
• It can cause damage to the flora and fauna of the particular area and public utilities.

Where does cloudburst occur?

• It occurs in high-altitude regions like hills and mountains due to the formation of low-pressure areas. These low-pressure areas accumulate clouds with great force on the top of mountains and result in orographic precipitation. Larger droplets of rain of about 5 cm can be formed in a certain cloudburst.
• In India, cloudburst occurs in states like Himachal Pradesh, Uttarakhand, Jammu and Kashmir. It is a common phenomenon in Himalayan areas, especially in Garhwal and Kumaon Himalayas. It is during the monsoons that they hit the hardest.

Prevention and Precaution 

• Since they are not predictable and take place over a small area, it is advisable to take necessary precautions before the cloudburst. Cloudburst can result in flash floods that can wash out everything in a matter of time. A constant update on the weather is highly recommended with early warning and decision support systems. In hilly areas, weather warnings can give ample time for mitigation, and thereby shifting to a safe shelter can be possible.
• Doppler’s radar, used for weather forecasting, can also be used to detect the possibility of a cloudburst. The chances of a cloudburst can be predicted six hours in advance. But they are expensive.
• Identifying areas of heavy rainfall can do a lot in evading the danger and minimizing the damage.
• Inhabitation of low-lying areas should also be reduced.

Cloudbursts and Rainfall

• Rainfall occurs when the moisture evaporates, condenses, and precipitates from the sky. Cloudbursts are abrupt, heavy rainstorms.
• Not all rainfalls are cloudbursts. Rains over 100 mm per hour are categorized as cloudbursts.
• Cloudburst occurs all of a sudden, with force, and is destructive.
• Rainfall and Cloudbursts only differ in the quantity of rain received.

National Disaster Management Authority

• NDMA is an apex body for the disaster management of the country.
• It is headed by the Prime Minister of India
• It was established on September 27, 2006
• Set up based on National Disaster Management Act, 2005
• Deals with the Mitigation, Prevention, Preparedness, and Response of National Disasters
• Formulates policies, plans, and guidelines for the management of disasters.

Frequently Asked Questions about Cloudburst

What are Cloudbursts?

Cloudbursts refer to intense precipitation over a geographical area, especially mountains, for a short period. The rain falls at a rate of 100 mm per hour over an area of approximately 20 to 30 sq km.

Why do cloudbursts occur?

Cloudbursts result in a condition where there is torrential downpour accompanied by hail and thunder. It occurs when the warm air currents block the raindrops from falling and causes an accumulation of water. When the upward currents are weak, there is a sudden downpour.

What is the difference between rainfall and cloudburst?

Cloudburst is an extreme amount of rainfall over a small area, mostly 100 mm per hour. It causes havoc and destruction on a large scale. Both differ in the quantity of rainfall recorded.

What are the effects of cloudbursts?

Cloudbursts can be destructive on a large scale, especially in the mountains, causing floods, landslides, and mudflows that create terrible losses in the life and livelihood of the masses.

How to prevent cloudbursts?

Proper and effective weather warning systems can be helpful indicators for people. Better infrastructure to modify homes in such a way to withstand floods can be another possible solution. Tackling climate change can positively impact weather phenomena and natural hazards.

Which cloud causes heavy rainfall?

Cumulonimbus clouds are responsible for heavy rainfall. They are convective clouds responsible for heavy rains accompanied by thunder, lightning, and hail.

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