What is cloud burst? When does it occures

A cloudburst is a sudden, very heavy rainfall that occurs in a short period of time—usually less than an hour—and is often highly localized (just a few kilometers wide). It is an extreme weather event that can lead to flash floods, especially in mountainous or hilly regions.

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Key Features of a Cloudburst:

1. Extremely Intense Rainfall:

   • Rainfall more than 100 mm (4 inches) per hour.
   • Can drop thousands of tons of water over a small area in minutes.

2. Very Localized:

   • Affects a small area (1–10 km wide), so nearby areas may have normal weather.

3. Short Duration:

   • Lasts from a few minutes up to an hour.

4. Often Unpredictable:

   • Difficult to forecast accurately due to its sudden nature.

5. Potentially Destructive:

   • Causes flash floods, landslides, damage to life and property, especially in hilly terrains like the Himalayas.

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How Does It Happen?

A cloudburst usually happens when:

• Warm, moist air rapidly rises due to convection.
• It cools quickly at higher altitudes.
• Water vapor condenses and forms large, dense clouds.
• Due to atmospheric instability, the cloud cannot hold the moisture, and it releases it all at once.

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Real-Life Example:

• Leh (Ladakh), India, 2010: Cloudburst led to flash floods, killing over 200 people and causing heavy destruction.
• Uttarakhand & Himachal Pradesh: Frequent incidents during monsoon.

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In Simple Terms:

A cloudburst is like the sky suddenly "dumping" water in one place, instead of a slow, widespread rainfall.

Cloud bursting in Uttarkashi

It appears there was a major cloudburst in Uttarkashi’s Dharali village yesterday (August 5, 2025). Here’s a summary of what happened:

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🌧️ What Took Place

A sudden, intense cloudburst hit Dharali village near Harsil around midday, triggering a flash flood and landslide, particularly in the Kheer Ganga / Kheer Gad area  .

The rushing waters swept away multiple homes, hotels, shops, and several villages, washing away structures and infrastructure within moments  .

Casualties & Missing

At least four people have died. The death toll may rise, and multiple fatality figures remain unconfirmed  .

More than 50 people are reported missing, with concerns that many may be trapped under the debris or swept downstream  .

Rescue & Response

Rescue operations are underway by the SDRF, NDRF, Indian Army (Ibex Brigade), and local emergency teams, deploying heavy machinery, sniffer dogs, and search teams as a top priority  

A helpline has been activated (number 9456556431) to assist affected families and pilgrims on the route  .

The Uttarakhand government has issued a red alert for Uttarkashi and surrounding areas through August 10, warning of continued heavy rainfall and potential landslides  .

Disruption & Impact

The region is part of the Gangotri pilgrimage route, and the calamity has severely disrupted access to key shrines and villages. Pilgrims and locals remain stranded or displaced  .

Power lines, roads, and bridges have been damaged; even livestock (e.g. goats in Barkot area) have been wiped out.

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🔍 Summary

What occurred in Uttarkashi on August 5, was a high-impact cloudburst causing destructive flash floods and landslides. So far, 4 confirmed dead, over 50 missing, with search-and-rescue in full swing amidst ongoing extreme weather alerts.

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If You Are in or Around the Area

• Avoid travel to lottery areas such as Dharali, Barkot, Harsil, or Gangotri roads.
• Keep phone numbers like 9456556431 handy for missing persons or help.
• Monitor official channels and weather advisories continuously.
• Stay away from rivers, streams, and landslide-prone slopes.

Why and when cloud bursting occurs?

A cloudburst occurs when warm, moist air rises rapidly and condenses into heavy clouds, which then release intense rainfall over a very small area in a very short time—usually minutes to an hour. Let's break this down.

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✅ Why Cloudbursts Occur:

1. Rapid Upward Movement of Moist Air (Convection):

• When hot air from the ground (especially in summer or monsoon) rises quickly into the cooler atmosphere,
• It carries a large amount of water vapor with it.

2. Condensation at High Altitudes:

• As this warm, moist air cools quickly, the water vapor condenses into heavy cumulonimbus clouds (storm clouds).
• These clouds can hold a lot of water in suspended form.

3. Cloud Becomes Oversaturated:

• If the cloud becomes too saturated and can’t hold the water, it collapses all at once.
• This causes a sudden release of rain, like pouring a bucket from the sky.

4. Geographical Factors:

• Mountains or hills (like the Himalayas) force the air upwards (called orographic lift), speeding up condensation.
• So, places like Uttarkashi, Himachal, and Kashmir are common sites.

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🕒 When Do Cloudbursts Usually Happen?

⛈️ Mostly During Monsoon (June to September in India):

• Warm temperatures + high humidity = perfect conditions for cloudburst.
• Often occur during late afternoon or night when humidity is at its peak.

⚠️ Weather Triggers:

• Sudden temperature changes
• Low-pressure zones
• Wind convergence (winds colliding from opposite directions)

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📍 Where Are They Most Common?

Region	Why It’s Vulnerable
Himalayas (Uttarakhand, Himachal, J&K)	Mountains push moist air upward quickly
Western Ghats (Kerala, Maharashtra)	Moisture-laden winds from Arabian Sea hit hills
North-East India	Heavy monsoon currents and hilly terrain

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🌀 In Simple Words:

A cloudburst is like the sky breaking open over a small area. It’s caused when too much water vapor builds up in the sky, can’t hold anymore, and dumps all the rain at once—just like breaking a water balloon.

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