Que. What is the phenomenon of ‘cloudbursts’? Explain.
‘बादल फटने’ की परिघटना क्या है? व्याख्या कीजिए।
Structure of the Answer
(i) Introduction: Define cloudbursts and highlight their significance, particularly in vulnerable regions prone to extreme rainfall events, using a concise description.
(ii) Main Body: Explain the formation, causes, and impacts of cloudbursts, supported by recent examples, and propose mitigation strategies.
(iii) Conclusion: Summarize the importance of early warning systems and climate adaptation to mitigate the impact of cloudbursts and reduce damage.
Introduction
According to Indian Meteorological Department (IMD) cloudbursts refer to a weather phenomenon where unanticipated precipitation exceeds 100 mm per hour over an area of about 20-30 square kilometers. Cloudburst events are often associated with cumulonimbus clouds that cause thunderstorms and occasionally due to monsoon wind surges and other weather phenomena. Recent incidents of cloudburst in Kullu, Solan, Kinnaur have highlighted the phenomenon and associated consequences.
Phenomenon of Cloudbursts
(i) Localized Intensity: Cloudbursts release a significant volume of rain over a small area in a short span of time, often resulting in flash floods and rapid water accumulation. The recent cloudburst in Himachal Pradesh (2023) caused over 50 mm of rain in just 15 minutes, leading to extensive flooding.
(ii) Formation Process: Cloudbursts occur due to rapid upward movement of moist air in cumulonimbus clouds. This air cools and condenses, causing intense rainfall(orographic uplift of moist air , saturation, intense condensation can lead to intense cumulonimbus clouds taking in huge volumes of moisture that are dumped during cloudburst). This is seen in orographically dominant regions like Himalayas, Western Ghats and North-East where moist air from south westerly monsoon winds which bring copious amounts of moisture encounter mountains leading to orographic uplift.
(iii) Geographic Variability: Cloudbursts typically occur in mountainous regions like the Himalayas and the Western Ghats but are also increasingly observed in urban areas such as the Mumbai cloudburst (2005). This incident resulted in over 900 mm of rainfall, flooding the entire city within a few hours.
(iv) Challenges in prediction : Despite technological advances, the exact prediction of cloudbursts remains a challenge mainly attributed to small size, short duration and sudden development of thunderstorm and also due to the complexity of associated atmospheric processes which prevail in tropical regions like India . For instance, the Kedarnath disaster (2013), triggered by a cloudburst, was a stark reminder of the unpredictability and scale of damage these events can cause.
(v) Associated Thunderstorm Activity: Cloudbursts often occur alongside thunderstorms. As thunderstorms cause rapid air currents, these interact with moist air, triggering cloudbursts, as in the case of the Leh cloudburst (2010) that resulted in widespread devastation.
Causes of Cloudbursts
(i) Orographic Lifting and Convection: Mountains act as barriers, forcing humid air upwards where it cools and condenses, leading to intense localized rainfall. The Kinnaur cloudburst (2023) in Himachal Pradesh followed this pattern, with orographic lifting causing excessive rainfall in a short period.
(ii) Monsoon and Humidity: During the monsoon, high humidity levels combined with unstable atmospheric conditions create a conducive environment for cloudbursts. This was evident in the recent Jammu cloudburst (2023), which led to flash floods that destroyed villages and displaced thousands of people.
(iii) Temperature Gradients: Sharp differences in temperature between the surface and upper atmosphere lead to thermal convection, which promotes rapid cloud formation. The Uttarkashi cloudburst (2021) was a result of such atmospheric instability, exacerbated by the cooling effect in higher altitudes.
(iv) Climate Change as risk amplifier: Climate change is projected to increase the frequency and intensity of cloudbursts worldwide. As the air gets warmer, it can hold more moisture—and for a longer time. We call this the Clausius Clapeyron relationship. A 1-degree Celsius rise in temperature may correspond to a 7-10% increase in moisture and rainfall. This increase in rainfall amount does not get spread moderately throughout the season. As the moisture holding capacity of air increases, it results in prolonged dry periods intermittent with short spells of extreme rains. More, deeper cumulonimbus clouds form, and the chances of cloudbursts also increase.
(v) Urban Heat Islands: Faulty urbanisation and anthropogenic activities have turned urban spaces into heat islands, raising temperatures, contributing to atmospheric instability and intense convection with enhanced frequency. This phenomenon worsens the occurrence of cloudbursts, as seen in the Delhi cloudburst (2020), which led to severe flooding in urban areas.
Impact of Cloudbursts
(i) Flash Floods: Cloudbursts often cause flash floods, with water levels rising quickly due to outdated and inadequate drainage. The flash floods in Uttarakhand (2023) and Mumbai resulted from a cloudburst, washing away infrastructure and causing extensive loss of life.
(ii) Landslides, land subduction and mudslides : The heavy spells of rain on the fragile steep slopes trigger landslides, debris flows, and flash floods, causing large-scale destruction and loss of people and property . The recent cloudburst in Himachal Pradesh (2023) caused severe landslides, blocking roads and damaging homes.
(iii) Impact on Agriculture and food systems : Heavy rains destroy crops and lead to soil erosion, significantly affecting rural livelihoods. Cloudbursts in Ladakh (2021) destroyed large portions of farmland, causing long-term damage to the region’s agricultural output.
(iv) Loss of Infrastructure: Cloudbursts can severely damage infrastructure, including roads, bridges, and buildings. The Kinnaur cloudburst (2023) caused widespread damage to highways, cutting off access to remote areas and complicating rescue efforts.
(v) Casualties and Displacement: Cloudbursts lead to significant human and livestock casualties. The Leh cloudburst (2010) caused over 200 deaths and displaced thousands, showcasing the high human cost of these events. This leads to psychological and emotional turmoil and uncertainty for the victims.
Mitigation and Preparedness
(i) Improved Early Warning Systems: Advanced Doppler radar systems and satellite monitoring help predict the likelihood of cloudbursts. The Indian Meteorological Department (IMD) is working to strengthen forecasting capabilities, especially in vulnerable regions like the Himalayas.
(ii) Disaster Preparedness Plans: State governments in cloudburst-prone regions like Himachal Pradesh and Uttarakhand are developing disaster preparedness strategies, including evacuation plans, community awareness campaigns, and infrastructure resilience.
(iii) Climate Adaptation and Green Infrastructure: To counter climate change impacts, adopting green infrastructure, such as afforestation and rainwater harvesting, can mitigate flood risks. Such measures are being implemented in cloudburst-prone cities like Mumbai.
(iv) Sustainable Urban Planning: Urban areas require better drainage systems and flood management strategies to handle extreme rainfall events. The Smart Cities initiative in India is focusing on sustainable urban planning to reduce the impact of cloudbursts in metropolitan areas.
(v) International Collaboration for Climate Resilience: Countries like India are collaborating with global partners to develop climate-resilient infrastructure and share best practices in cloudburst forecasting and disaster response.
Conclusion
The change in monsoon extremes and cloudbursts we see now are in response to the 1-degree Celsius rise in global surface temperatures. As emissions continue to increase and global commitment to reduce emissions proves insufficient, these temperatures are set to hit 1.5°C during 2020-2040 and 2°C during 2040-2060. We will need urgent action and policies to protect lives and property from extreme events that will amplify as the global temperature change doubles.
