Lightning strikes in India: impacts and management – Explained, pointwise

Introduction

Climate change may be sparking more lightning across the world, and there is an increasing scientific evidence pointing to the trend. According to a pre-print accepted for the journal Atmospheric Chemistry and Physics recently, the frequency and intensity of lightning strikes in India are expected to increase by 10-25 percent and 15-50 percent by the end of this century. Coastal areas may be at the highest risk.

In India, over the recent years, there’s an increasing trend in death toll and damages reported due to lightning. Lightning strikes kill more people in India than any other extreme weather event, causing more than 2000 deaths every year.

Global studies regarding Lightning

• A study published in 2015 found out that, an increase of one degree Celsius would increase the frequency of lightning strikes by 12 percent.
• A study published in Geophysical Research Letters in March 2021, too, has established links between climate change and rising incidences of lightning in the Arctic region.
  • The number of lightning strikes recorded during the summer months between 2010 and 2020 shot up from around 18,000 at the start of the decade to more than 150,000 by 2020.
• Another research finds out that, Urbanisation, increased population and a warmer climate guarantee an intensification of human exposure to lightning hazards.
• An increase in lightning incidents may be directly related to the climate crisis and the availability of more moisture over land due to warming.
• Scientists also found out the link between cloud burst events, which cause sudden heavy rainfall often triggering flash floods, and forest fires.

Lightning in India

• As many as 18.5 million lightning strikes were recorded in India between April 1, 2020, and March 31, 2021, according to India’s second annual report on lightning released by Lightning Resilient India Campaign (LRIC) recently. This is an increase of 34 percent compared to the previous year.
• At least 1,697 people died due to lightning between April 1, 2020, and March 31, 2021. Of this, 401 died in Bihar, followed by Uttar Pradesh (238 deaths) and Madhya Pradesh (228 deaths).
• Lightning strikes increased in Punjab 331 per cent, followed by Bihar (168 per cent), Haryana (164 per cent), Puducherry (117 per cent), Himachal Pradesh (105 per cent) and West Bengal (100 per cent).

What is lightning?

Lightning is a very rapid and massive discharge of electricity in the atmosphere. It 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. 

• These discharges are generated in giant moisture-bearing clouds that are 10-12 km tall. These clouds have their bases about 1-2 km from the Earth’s surface.
• There are two types of lightning. Such as,
  • Intercloud or intracloud (IC) lightning: These are visible and harmless.
  • Cloud to ground (CG) lightning: This is harmful as the ‘high electric voltage discharge for very short time leads to electrocution.

How does lightning strike?

1. It is a result of the difference in electrical charge between two points.
2. As water vapour moves upwards in the cloud, the falling temperature causes it to condense. A huge amount of heat is generated in the process, pushing the water molecules further up.
3. As they move to temperatures below zero, droplets change into ice crystals. This leads to a system where smaller ice crystals move upwards while larger ones come down.
4. The resulting collisions trigger the release of electrons. This process is similar to the generation of electric sparks. The moving free electrons cause more collisions and more electrons, leading to a chain reaction.
5. Over time, this process results in a situation where the top layer of the cloud gets positively charged and the middle layer is negatively charged.
6. The electrical potential difference between the two layers is huge (a billion to 10 billion volts). So, in a short time, a massive current (100,000 to a million amperes) starts to flow between the layers.
7. An enormous amount of heat is produced, and this leads to the heating of the air column between the two layers of the cloud. As the heated air column expands, it produces shock waves that result in thunder.
8. The Earth is a good conductor of electricity, it is electrically neutral. However, in comparison to the middle layer of the cloud, it becomes positively charged. As a result, about 15%-20% of the current gets directed towards the Earth as lightning.

Losses due to lightning

• Apart from human and animal loss, lightning can also cause the following losses.
• Economic losses like that of cultivated fields and buildings occur, infrastructure like communication networks, power plants and so on are often destructed by lightning events.
• Sometimes, lightning and thunderstorms may ignite potentially devastating wildfires.

Government safety guidelines to reduce lightning impact

• National Disaster Management Authority (NDMA) has issued detailed guidelines on action-plan by state and local authorities. The NDMA guidelines follow a community-centric approach. “These guidelines, drawn from international best practices, provide do-s and don’t-s as well as steps to be taken by common people”.
• In pre-and post-monsoon season, NDMA conducts workshops with all stakeholders to discuss preparedness and mitigation measures for reducing the impact of thunderstorms & lightning, dissemination of early warnings at a local level, SOPs and so on.
• NDMA also works on improving inter-agency coordination which includes monitoring and reviewing mechanisms at field level, forecasting and dissemination of nowcast warnings of IMD, etc.
• India is among a few countries which has introduced a Lightning Warning System. This system has a location-specific forecast up to 48 hours about the occurrence of thunderstorms, lightning, squally winds, gusty winds, hailstorms.
• Besides, ISRO is providing satellite information from INSAT-3DR about convective clouds, which is uploaded every 15 mins.
• Damini App was developed by the Indian Institute of Tropical Meteorology (IITM-Pune) and Earth System Science Organization (ESSO) under the ministry of earth sciences.
  • The app monitors the lightning occurrence all over India and alerts the user of lightning near them by a GPS notification under 20 km and 40 km.
  • Further, the Damini app also triggers warning about lightning strikes three hours in advance which can help reduce losses to life and property.
• ‘Lightning Resilient India Campaign‘:
  • It is a joint initiative of Climate Resilient Observing-Systems Promotion Council ( CROPC), NDMA, India Meteorological Department (IMD), Union Ministry of Earth Science, World Vision India, UNICEF among others.
  • The campaign aims to reduce the number of deaths to less than 1,200 a year by 2022.

Suggestions

• A systematic approach in managing the risks associated with these disasters can prevent or mitigate their impact.
• IMD’s timely weather warnings need to reach out to people at remote corners. In this context, NDMA has constituted an expert committee to develop a protocol on early warning and forecasting dissemination on thunderstorms and lightning.
• The report on lightning released by LRIC recommends States should undertake lightning micro-zonation for the regions depending on their geography to handle the disaster and death risks better.
• Multi-stakeholders engagement at the national and state level with governments, academia, non-profits and communities, has been successful in bringing down deaths by more than 60 percent within two years. So, the government has to intensify such collaboration.

Source: Down To Earth, PIB