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Overview of Cloudburst: Mechanism, Causes, Impact & Initiatives
Context: Recently, a cloudburst in Kedarnath caused significant damage, leading to a sharp rise in the Mandakini River’s water level in Sonprayag.
More on news:
- The cloudburst triggered a landslide in the Bhim Bali stream along the Kedarnath walking path, damaging about 30 metres of the route. The path has been temporarily closed for safety.
- Stranded Pilgrims: Authorities are concerned that between 150 to 200 pilgrims might be stranded in Kedarnath. Emergency services, including the State Disaster Response Force (SDRF), district police, and local officials, are on high alert.
- Recently, heavy rainfall in Haridwar led to severe flooding.
- Kharkhari River overflowed causing damage.
- Recently, heavy rain-induced landslides in Wayanad district, Kerala, resulted in over 150 fatalities.
- The shifting of the monsoon trough northwards from its usual position contributed to the extreme weather events in Delhi, Himachal Pradesh, and Uttarakhand.
- The IMD described the heavy rainfall in these regions as “extremely intense spells.”
Cloudbursts
Cloudbursts are a natural and common phenomenon in the Himalayas, though they can also occur in plains.
- In India, cloudbursts typically happen during the southwest monsoon season in regions with significant orographic features, such as the Himalayan region, northeastern states, and the Western Ghats.
- Predicting cloudbursts is challenging due to their small size, short duration, and sudden development, as well as the complex atmospheric processes common in tropical regions.
The Basic Mechanism of a Cloudburst Involves the Following Process:
- Orographic Lift: The primary cause of this phenomenon is orographic lift, where the terrain influences the cloud formation and precipitation process.
- Warm air currents from the terrain push saturated clouds upwards along the mountains.
- Formation of Cumulonimbus Clouds: This upward movement, along with the warm air, leads to the formation of Cumulonimbus clouds.
- Intense Precipitation: As these clouds accumulate more water vapour and raindrops, they eventually reach a point where they can no longer hold the moisture.
- Cloudburst: The cloud then releases the accumulated water with great strength and velocity, resulting in intense rainfall over a small area in a short duration.
The aftermath of a cloudburst can be severe and include:
- The cloudburst triggered debris flows and flash floods which impacted the environment and economy.
- Damage to households.
- Loss of human and animal lives.
- Destruction of buildings and property.
- Destruction of forests.
- Damage to current crops and fruits.
- Loss of arable land.
- Destruction of bridges and flyovers.
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Landslides:
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Measurement Steps taken by Indian Government:
- Doppler Weather Radar (DWR): The India Meteorological Department (IMD) tracks thunderstorm activities and potential cloudbursts using its surface observation and DWR networks, which provide cloud images and wind velocities every ten minutes for real-time monitoring and nowcasting.
- Numerical Weather Prediction (NWP): IMD also employs high-resolution NWP models for short-term thunderstorm forecasts and issues warnings through various channels, including social media.
- Automatic Weather Stations (AWS): To enhance weather monitoring, IMD is setting up AWS in every block and installing automatic rain gauges in every panchayat across the country.
Way Forward:
- Doppler Weather Radars: Short-term forecasting (nowcasting) with radars provides crucial warnings, though widespread deployment is costly.
- Automatic Rain Gauges: Long-term mapping of cloudburst-prone areas using these gauges enhances preparedness.
- Risk Assessment: Designate hazardous sites prone to cloudbursts and landslides, and implement relocation and activity restrictions to reduce risks.
- Cloudburst Management: Integrate methods to manage stormwater, using both grey (sewers, storage tanks) and green (trees, rain gardens) infrastructure to minimise flooding and property damage.
- Preventive Policies: Develop policies to protect lives and property from increasing extreme weather events due to climate change.
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Impact of Climate Change on Increasing Cloudburst Events:
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