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Dharamshala Cloudburst triggers flash flood and destruction of property

Dharamshala Cloudburst triggers flash flood and destruction of property

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  • GS 3 || Disaster Management || Major Disasters || Cloud Bursts

Why in the news?

  • There have been massive flash floods in Dharamshala(HP) after a cloudburst occurred there. Cloudburst has blocked the national highway near Jhakri in the Rampur area of Shimla district.

What is a cloud burst?

  • The India Meteorological Department (IMD) defines a cloudburst as any event where 100 millimeters of rainfall have fallen in an hour over a region that is 20-30 square kilometers in area.By this definition, 5 cm of rainfall in half an hour would also be classified as a cloudburst.

Impact of Cloudburst

  • This leads to flash floods/ landslides, house collapse, dislocation of traffic, and human casualties on a large
  • In addition, as pointed out earlier, cloudbursts get counted only when they result in large-scale destruction of life and property, which happens mainly in mountainous regions.
  • Accompanying effect of Cloudbursts on terrain
    • Landslides
    • Mudflows
    • Land caving
  • Flash floods –houses and establishments getting swept away and cave-ins lead to deaths.
  • Blocking the path of rivers that may lead to temporary damming and the creation of a reservoir and its consequent collapse
  • The rainfall itself does not result in the death of people, though sometimes, the raindrops are big enough to hurt people in a sustained downpour. It is the consequences of such heavy rain, especially in the hilly terrain, that causes death and destruction.

Disasters due to  Cloudbursts of the past

  • Chamoli district- May 2021
    • Several cloudbursts caused several homes and roads in several villages in Uttarakhand’s Chamoli, Tehri, and Rudraprayag districts to be flooded with water and debris in early May 2021.
  • Uttarakhand Floods-2013
    • The most devastating disaster in India due to cloudbursts was the Uttarakhand floods and landslides of 2013, which were preceded by heavy rainfall before a cloudburst that triggered flash floods. The total death toll was about 5,700 deaths, making it the 5th deadliest global landslide event in terms of fatalities.
    • The multi-day cloudburst in the hill state of Uttarakhand triggered flash floods and massive landslides.
    • Uttarakhand is highly prone to cloudburst events. Nineteen of the 30 major cloudburst events reported from the southern rim of the Himalayas occurred in Uttarakhand.
  • Ladakh Floods- 2021
    • A major cloudburst and heavy rainfall on the intervening night of August 6, 2010, triggered mudslides, flash floods, and debris flow in Jammu and Kashmir’s Ladakh. 71 towns and villages in Leh were affected in the region and at least 255 people died.

Vulnerable areas

  • Hilly regions are more prone though happens in plains as well
    • Cloudbursts do happen in plains as well, but there is a greater probability of them occurring in mountainous zones; it has to do with the terrain. Cloudbursts happen when saturated clouds are unable to produce rain because of the upward movement of the very warm current of air.
  • Hilly terrains aid in heated air currents rising vertically upwards, thereby, increasing the probability of a cloudburst situation.
  • The Chota-Nagpur plateau spread across north Odisha, West Bengal and Jharkhand is the world’s most vulnerable spot for the formation of severest thunderstorms.

Prediction/ Forecasting of Cloud bursts

  • They are difficult to forecast but not impossible; the difficulty arises out of the fact that they take place over a very small area. Forecasts for a very small area are difficult to predict.
  • The large-scale features that favor the occurrence of severe thunderstorms with cloudbursts are predictable two to three days in advance.
  • Doppler Radars
    • The precise location and timing of a cloud burst can only be predicted in NOWCAST mode, i.e. a few hours before the genesis of a thunderstorm has begun.
    • A Doppler Weather Radar (DWR), a powerful tool for time and location-specific cloudburst prediction, can be deployed a few hours in advance to detect these sudden developments. When combined with satellite imagery, this data can be used to extrapolate cloudbursts anywhere in India.

Frequency of cloudbursts

  • There is a paucity of past data on cloudbursts; in addition, since only some of them get counted – only those that result in death and destruction – there is a problem of accuracy as well.
  • But what is very clear is that events of extreme precipitation have been on the rise in the last few decades; keeping temperature fluctuations in mind as a trend, that cloudburst events might be on the increase as well.

Mitigation of cloudbursts

  • Regulation of construction activities along river banks with special consideration to water level during heavy rainfall.
  • Reinvigorating the SDMA with adequate resources (funds and personnel)
  • Localized planning taking into consideration the ecologically fragile nature of the region and involving the local communities
  • Better forecasting by IMD and incorporation of advanced technology to monitor and predict extreme weather events can enable early warning, evacuation, and preparedness
  • Adoption of eco-friendly policies and eco-sensitive tourism for the development of the region.
  • Incorporation of disaster management and prevention into the developmental planning process.
  • Rescue and relief and evacuations cannot be enough due to the sudden nature of the disaster. The best solution has to be a solution inbuilt into our habitations whereby the effects of cloudbursts can be mitigated therein. One such mechanism is being planned in the city of Copenhagen, Denmark.
    • Copenhagen as a model
      • A useful model in cloudburst mitigation is Copenhagen, whose municipal department has organized a cloudburst master plan coupled with concretization plans. The plan aims to decouple 30 to 40 percent of the excess stormwater from the combined sewer system to level out the expected 40 percent excess rainfall due to climate change over 100 years.
      • The plan incorporates both concretizations, the creation of canals, and the greening of Copenhagen.
      • Copenhagen represents the way forward in long-term planning for some of the aberrations that might be caused by climate change. An inbuilt mechanism to combat a disaster is the best solution, provided it delivers.

Recent initiatives

  • The National Institute of Disaster Management (NIDM) organized the 1st International Conference on “Landslides Risk Reduction and Resilience” in November 2019 in New Delhi.
  • Hosted the South Asian Annual Disaster Management Exercise (SAADMEx) and the Asian Ministerial Conference for Disaster Risk Reduction (AMCDRR).
  • India has also offered its expertise and capabilities in DRR such as the South Asia satellite, GSAT-9, and the Tsunami Early Warning Centre to other countries.
  • Disaster Management was one of the important Agenda items the BIMSTEC leaders deliberated upon during the Goa BRICS Summit in October 2016 where BIMSTEC leaders were the Special Invitees.

Conclusion

  • NDMA guidelines emphasize community-Based Disaster Management (CBDM). Utilization and leverage of local knowledge, resources can have a multiplier effect on mitigation.
  • Participation and co-operation of local bodies such as NGOs, Gram Sabhas, Panchayats can strengthen the entire framework of disaster management.

Mains model question

  • Discuss the phenomenon of cloudburst and how it differs from normal rainfall. Examine the Indian aspect of it.

References