Other Water and Climate related disasters : news and updates

What is the News?

Recently, 18 elephants died on a hilltop in Assam. The preliminary post-mortem report indicates they had been struck by lightning.

Process of formation of lightning

• During a storm or rain, particles of rain, ice, or snow inside storm clouds collide with each other. It creates a negative charge in the lower reaches of storm clouds and a positive charge in the upper reaches of clouds. This imbalance results in inter-cloud lightning.
• Ground Objects like trees and earth itself during storms become positively charged due to friction with particles. It creates an imbalance between earth and cloud. Thus, nature seeks to balance this by passing current between the two charges i.e. from clouds to earth.
• Thus, lightning is the process of occurrence of a natural electrical discharge of very short duration and high voltage between a cloud and the ground or within a cloud. It is accompanied by a bright flash and sound and sometimes thunderstorms.
• Types:
  • Inter cloud or intra cloud(IC) lightning are visible and are harmless.
  • It is cloud to ground (CG) lightning that is harmful as the ‘high electric voltage and electric current’ leads to electrocution.

How does lightning kill animals? Lightning may injure or kill animals in a number of ways such as:

• Direct Flash: An animal in an open field may be struck directly by lightning if part of its body covers or is over other objects in the vicinity. Taller animals are more vulnerable.
• Side Flash: When lightning strikes a tall object such as a tree, it may generate a side flash that can strike an animal standing underneath the tree.
• Touch Potential: If one part of a tall animal’s body is in contact with the ground, while another part touches a lightning-struck object like a tree, a partial current may pass through its body.
• Step Potential: It is the most common lightning hazard among four-legged animals. When an animal’s front and hind feet are far enough apart, a partial current may pass through the body in certain circumstances.

As per the investigation team, it may be the step potential that killed the Elephants.

Why are elephants more vulnerable to lightning?

• An elephant’s front and hind feet are wide apart. Therefore, it would appear to make it more vulnerable than a smaller animal, such as a rat.
• This is because the potential difference increases with the increasing distance between the two feet. The larger the potential difference, the greater the current through the body.

Source: Indian Express

Synopsis: There are various reasons for Disasters in Uttarakhand. It can be prevented by taking some long-term measures.

Background:

• The glacier burst in the Chamoli district of Uttarakhand caused the flash floods. It led to the death of 34 people with more than 170 people missing.
• Apart from that, it also caused destruction to public and private infrastructure. For example, It damaged the NTPC’s Tapovan-Vishnugad hydropower project and the Rishiganga mini-hydro project.
• The recent disaster reminds the 2013 disaster in Uttarakhand which resulted in the death of thousands of people.
• The scientific community still doesn’t have the exact reason for the cause of this disaster.

What are the possible reasons for the cause of the disaster in Uttarakhand?

The scientific community still doesn’t have the exact reason for this disaster. However, some possible reasons are discussed below.

• First, the Natural ecology of Uttarakhand and its fragile mountain ecosystem is prone to such disaster. Uttarakhand is located between the young and unstable mountains. Moreover, intense rainfall makes it more vulnerable.
• Second, as per geologists, glaciologists, and climate experts, climate change, rapid and indiscriminate construction activities, and the subsequent ecological destruction are disturbing the balance of the ecosystem in this region.
  • • For example, The Hindu Kush Himalaya Assessment Report (2019) had pointed out that one-third of the Hindu Kush Himalaya’s glaciers would melt by 2100. It may happen even if all the countries in the region fulfilled their commitments under the Paris Agreement.
    • It also warned that any ecologically destructive activities would lead to more intensified disasters like landslides.
• Third, according to the Wadia Institute of Himalayan Geology, rock mass might have weakened due to intense freezing and thawing of snow. This may have created a weak zone. Fractures led to a collapse that resulted in flash floods.
• Fourth, Experts also opine that massive deforestation is a possible reason for the disaster. For example, in 2014, the Chopra committee established that the haphazard construction of dams can cause irreversible damage to the region.
• Fifth, there are also possibilities that the use of explosives in the construction of dams and other infrastructure would have weakened the rock strata.

What needs to be done?

• First, Government should Invest in long-term crisis response mechanisms and resilience solutions such as,
  • • Flood prevention and rapid response.
    • Road stabilization technologies for fragile road networks, bridges, culverts, and tunnels.
    • Strengthening embankments using scientific knowledge.
    • Investing in monitoring and early warning system.
    • Investing in training and capacity building of local communities to prevent and manage risks effectively.
• Second, hydropower and other public infrastructure projects need reassessment based on the sensitivity of local ecology.
• Third, implementing pragmatic policies and regulatory guidelines such as responsible eco- and religious tourism policies. This will restrict detrimental human activities.
• Fourth, applying innovative and inclusive solutions that support nature and marginalized communities, to restore and rebuild a resilient future for Uttarakhand.

What is the News?

The rescue operations are still undergoing in Uttarakhand from a Tapovam tunnel located at the Tapovan-Vishnugad hydro project.

 Facts:

• Tapovan Vishnugad Hydropower Plant is a 520 MW run-of-river hydroelectric project(See image). It was constructed by National Thermal Power Corporation Limited(NTPC) on Dhauliganga River in Chamoli District of Uttarakhand.

• The power plant is located on the downstream on the Alaknanda River (one of the two headstreams of the Ganges).
• Damaged: It was severely damaged in February 2021 due to flash flood caused by Uttarakhand glacier burst.

Read more about Glacial Lake Outburst Flood (GLOF)

 Source: The Hindu

What is the News?

According to glaciologists and experts, the cause of flash floods in Uttarakhand Chamoli district was most probably a landslip(Landslide) and not a glacial lake burst.

Why are experts calling it a Landslide and not a glacial lake burst?

• The glacial lake outburst flood(GLOF) occurs when a natural lake, formed from a glacial ice melt and the glacial lake is breached. However, available satellite images do not show the presence of a glacial lake before the flooding event.
• Moreover, the Central Water Commission(CWC) monitors and prepares monthly reports on the state of glacial lakes and waterbodies measuring 10 hectares and above via satellite. Nothing out of the ordinary was observed by CWC.

Then, what might have caused the flooding?

• There was a hanging glacier and on top of the glacier was a huge rock mass.
• The rock mass became loosened due to freezing, thawing, and temperature variation. It came crashing down, creating pressure on the hanging part of the glacier. The fresh snowfall had also been added to the weight over the hanging glacier.
• This hanging glacier broke off due to gravitational pull, slid down with the entire rock mass. It slowed down near the base of the valley, where the Raunthi Gadhera stream flows.
• As the huge mass slowed a bit, then stopped, it blocked the water of the stream and the water quantum kept increasing. This damming up of the stream increased to such an extent that it breached the whole accumulated mass of water.
• Hence, this whole mass of water, boulders, and rock mass came crashing down with force towards the Rishi Ganga dam site. It caused massive damage to the under-construction Tapovan hydel project and caused floods.

Source: The Hindu

 More Related post

https://forumias.com/blog/glacial-lake-outburst-flood-glof-in-uttarakhand-explained/

https://forumias.com/blog/glacial-lake-outburst-floods-glof/

https://forumias.com/blog/what-are-the-ndma-guidelines-for-glofs-related-disasters/

What is the News?

NDMA has issued guidelines to reduce disasters related to Glacial Lake Outburst Floods (GLOFs). Recently GLOF is suspected to have caused the flash floods in Uttarakhand’s Chamoli.

What are Glacial Lake Outburst Floods(GLOFs)?

• It refers to the flooding that occurs when the water dammed by a glacier or a moraine is released suddenly.

 Click Here to Read Further on GLOFs

• According to National Disaster Management Authority (NDMA), Climate change is facilitating the glacial retreat in most parts of the Hindu Kush Himalayas. It is resulting in the formation of numerous new glacial lakes. Due to that, this area has become prone to GLOFs.

NDMA Guidelines for Reducing GLOFs:

The NDMA, headed by PM, had issued detailed guidelines on how to reduce and deal with disasters caused by GLOFs:

• Identify and Mapping Dangerous Lakes: Potentially dangerous lakes can be identified. This identification will be based on field observations, past events, geomorphologic and geotechnical characteristics, etc.
• Use of Technology: It has recommended the use of Synthetic-Aperture Radar imagery. It will automatically detect changes in water bodies, including new lake formations, during the monsoon months.
• Structural Measures: It recommends reducing the volume of water with various methods to manage lakes structurally. Methods are pumping or siphoning out water and making a tunnel through the moraine barrier or under an ice dam.
  • Example: In 2014, a landslide occurred along Phuktal (tributary to Zanskar river) in Kargil district of Ladakh. It led to a potential flood situation. The NDMA created an Expert Task Force which along with the Army used explosives to channel water from the river. It used controlled blasting and manual excavation of debris for this purpose.
• Constructions and development in High prone areas should be prohibited. It is a very efficient means to reduce risks at no cost.
• Land Use Planning: Land use planning regulations need to be developed. In downstream areas, Infra. development should be monitored prior to, during, and after the construction.
• Trained Local Manpower: Apart from specialized forces such as NDRF, ITBP, and the Army, there is a need for trained local manpower. These teams will assist in planning and setting up emergency shelters, distributing relief packages, identifying missing people, and addressing the needs for food, healthcare, water supply, etc.
• Early Warning System: A robust early warning system in vulnerable zones should be put in place.
• Emergency medical response team: Quick Reaction Medical Teams, mobile field hospitals, Accident Relief Medical Vans, and heli-ambulances should be set up in areas inaccessible by roads.
• Psychological Counselling: The guidelines also call for psychological counseling of victims.

Source: Indian Express

What is the News?

Parts of Uttarakhand witnessed massive flooding due to Glacial Lake outburst.

 What is Glacial Lake Outburst Floods(GLOF)?

• It is a type of outburst flood. It occurs when water dammed by a glacier is released. In other words, it’s an outburst that happens when a dam containing a glacial lake fails.

Note: An event similar to a GLOF, where a body of water contained by a glacier melts or overflows the glacier is called a jökulhlaup.

How does GLOF happen?

• Retreating glaciers, like several in the Himalayas, usually result in the formation of lakes at their tips, called proglacial lakes. It is often bound only by sediments and boulders.
• If the boundaries of these lakes are breached, it can lead to large amounts of water rushing down to nearby streams and rivers. It gathers momentum on the way by picking up sediments, rocks, and other material, and resulting in flooding downstream.

Features of GLOF: The three main features are:

• They involve sudden (and sometimes cyclic) releases of water.
• They tend to be rapid events, lasting hours to days.
• Furthermore, they result in large downstream river discharges (which often increase by an order of magnitude).

Causes behind GLOFs

The boundaries of glacial lakes breach due to multiple reasons. Like,

1. A buildup of water pressure or structural weakness of boundary due to an increase in the flow of water.
2. An earthquake (Tectonic) or cryoseism (non-tectonic seismic event of the glacial cryosphere) can also cause GLOF. During this, the boundary of the glacial lake will collapse suddenly and release the water in the glacial lake.
3. An avalanche of rock or heavy snow: During this, the water in the glacial lake might be displaced by the avalanche.
4. Volcanic eruptions under the ice can also cause GLOF. These volcanic eruptions might displace the boundary or increase the pressure on glacial lake or both.
5. Heavy rainfall/melting of snow: This can lead to massive displacement of water in a glacial lake.
6. Long-term dam degradation can also induce GLOF.
7. Other reasons such as the collapse of an adjacent glacial lake, etc.

What are Glaciers?

• Glaciers are made up of fallen snow. It compresses into large, thickened ice masses over a period of time. They are formed when snow remains in one location long enough to transform into ice.
• Where are Glaciers found? Glaciers are found on every continent except Australia. Some are hundreds of thousands of years old. A large cluster of glaciers are in the Himalayas, which are part of India’s long northern border.

Source: The Hindu

Why in News?

As per a new study, the number of flash droughts could be increased in India, by the end of this century.

Facts:

• Flash droughts: These droughts occur very quickly due to the rapid depletion of soil moisture. It is different from normal drought conditions, that develop in months, but the flash drought happens within a week or two.
• Factors: Several factors including Lesser precipitation, high temperature, anthropogenic greenhouse gas emissions play an important role in the occurrence of flash droughts.
• Flash droughts in India: The top five flash droughts in India based on the overall severity score occurred in 1979 (about 40% of the country was affected) followed by 2009, 1951, 1986, and 2005.

Key Takeaways from the study:

• The ongoing climate change has caused a significant increase in global temperature. It can lead to more and more flash droughts in the coming years.
• There is a five-fold rise in the frequency of extremely dry and hot years in the coming three decades. This is causing an approximately seven-fold increase in flash droughts like 1979, by the end of the 21st century.
• Impact: The increased frequency of flash droughts can have severe implications for crop production, irrigation demands, and groundwater abstraction in India.

Suggestions:

• Limiting Global Warming: By limiting global warming to well below 2 degrees C, the numbers and frequency of the projected flash droughts may go down.
• Predicting flash droughts: Flash-drought prediction ahead of time using operational meteorological forecasts will help manage irrigation water demands and avoid considerable losses in agriculture.

Source: The Hindu

News: According to a report, Lightning strikes have caused 1,771 deaths between April 1,2019 and March 31,2020 in India.

Facts:

• The report has been prepared by Climate Resilient Observing Systems Promotion Council(CROPC), a non-profit organisation that works with India Meteorological Department(IMD), Indian Institute of Tropical Meteorology(IITM), India Meteorological Society(IMS) and World Vision India to disseminate early lightning forecasts.

Key Takeaways:

• State Wise Deaths due to Lightning Strikes: Uttar Pradesh with 293 deaths, Madhya Pradesh 248, Bihar 221, Odisha 200 and Jharkhand 172 deaths together accounted for more than 60% of the numbers which are 33% of total fatalities from all natural disasters during the time period.
• Highest Lightning Strikes State: Odisha had 11.20 lakh plus lightning strikes—the highest in the country—with 200 casualties. During Cyclone Fani, the state saw more than one lakh intense lightning strikes in 2019.
• Deaths due to Lightning: The reason for death due to Lightning is because people are unaware and about 78% deaths took place due to people standing under isolated tall trees.About 22% of the people were struck in the open.
• Why are lightning strikes increasing? The report mentions that the lightning is direct promulgation of climatic extremities like global warming, deforestation, depletion of water bodies, concretisations, rising pollution and aerosol levels have cumulatively pushed the environment to extremes.

Recommendations:

• Lightning needs to be listed as a notified disaster by the Ministry of Home to get required attention in national policy directives and developmental programmes.
• Implement a local lightning safety action plan like installing Lightning Protection Devices.
• Need of Scientific and Community Centric approach: National Disaster Management Authority(NDMA) has issued guidelines for preparations of Lightning action plans to states.But the large number of fatalities show the implementation also needs a more ‘scientific and focused community centric approach’ as well as convergence of various departments.
• A National Lightning Resilience Programme is needed to identify the precise risk in terms of lightning frequency, current intensity, energy content, high temperature and other adverse impacts.
• Early lightning warning to farmers, cattle grazers, children and people in open areas.

Additional Facts:

• What is Lightning: Lightning is the process of occurrence of a natural electrical discharge of very short duration and high voltage between a cloud and the ground or within a cloud accompanied by a bright flash and sound and sometimes thunderstorms.
• Types: Inter cloud or intra cloud(IC) lightning which are visible and are harmless. It is cloud to ground (CG) lightning which is harmful as the ‘high electric voltage and electric current’ leads to electrocution.
• Technology: CROPC has a MOU with the India Met Department (IMD), Ministry of Earth Science(MoES) to disseminate early lightning forecasts which uses satellite observations, inputs from ‘network of Doppler and other radars’, ‘lightning detection Sensors’ among others.
• Origin of Lightning: Most Lightning strikes originate from Chotanagpur Plateau – the confluence of Odisha, West Bengal and Jharkhand—and extended to Bangladesh to Patkai plateau of Meghalaya affecting other North eastern states.