Need for more weather safety awareness and lightning warning tools to save human lives
Media reports indicate that at the start of the southwest monsoon season, lightning strikes caused the death of over 70 people in the states of Rajasthan, Uttar Pradesh and Madhya Pradesh on a single day i.e. 11th July, 2021. Prior to those separate events related to human casualty caused by thunderbolts, eighteen elephants were found dead on a hilltop at Kandali Proposed Reserve Forest situated in Assam's Nagaon district on 13th May this year. Experts believe that they were electrocuted by lightning. Although it would be difficult to save the lives of wild animals, human casualty to a large extent can be prevented if prior information about the possibility of such lightning bolts is disseminated at the right time.
The Earth Networks Global Lightning Network (ENGLN), which monitors the combination of in-cloud and cloud-to-ground lightning strikes over 100 countries, is considered to be the most extensive and technologically advanced total lightning network in the world. The ENGLN has been specifically deployed to detect real-time lightning and provide advanced warning for severe weather events that could threaten public safety and operational efficiency. In a recent report prepared by ENGLN, granular data on in-cloud, cloud-to-ground, and total lightning strikes from India, Bangladesh, Sri Lanka and the surrounding water bodies during 2020 has been provided. The counts, rankings, and Dangerous Thunderstorm Alerts (DTAs) provided in the report titled South Asia Lightening Report 2020 are from January 1, 2020 to December 31, 2020.
The report by ENGLN has warned that India is susceptible to extreme amounts of heat and moisture due to the country’s proximity to the equator and the Indian Ocean. As a result of these factors, acute thunderstorm weather throughout South Asia (including India, Bangladesh and Sri Lanka) is quite common. Severe weather conditions and the dangers of lightning pose a great threat to the people of South Asia. The South Asia Lightening Report 2020 cites a study by the National Crime Records Bureau (NCRB) -- a department specialising on data and statistics under the Ministry of Home Affairs (MHA) -- that says that since 2001, 2,360 people die in the country annually due to lightning strikes. Despite their smaller geographical areas, severe lightning critically affects the populations of Bangladesh and Sri Lanka.
According to the South Asia Lightening Report 2020, the Earth Networks Global Lightning Network, in short ENGLN, detected about 3.95 crore lightning pulses in India during the calendar year 2020, of which 1.3 crore were dangerous cloud-to-ground lightning pulses (i.e. 32.9 percent of the total number of lightning pulses in the calendar year 2020) and the rest 2.65 crore were in-cloud lightning pulses (i.e. 67.1 percent of the total number of lightning pulses in 2020). Kindly note that a pulse is a surge of electric current in lightning usually accompanied by a burst of light. Pulses are classified as in-cloud (IC) or cloud-to-ground (CG). Lightning that happens between opposite charges in a cloud and on the ground is termed as cloud-to-ground lightning (CG). Lightning that occurs between opposite charges within a thunderstorm cloud is termed as in-cloud lightning (IC) by the report.
In comparison to India, Bangladesh saw around 30 lakh total lightning pulses (i.e. 18,97,220 in-cloud and 11,15,375 cloud-to-ground) and Sri Lanka witnessed almost 1.44 crore total lightning pulses (1,38,87,772 in-cloud and 5,72,729 cloud-to-ground).
In terms of cloud-to-ground flashes (or cloud-to-ground lightning strikes), the most were observed in Odisha (12,65,695), followed by Chhattisgarh (10,79,151), West Bengal (9,40,958), Maharashtra (8,45,088) and Madhya Pradesh (8,10,288). In terms of in-cloud lightning flashes, the most took place last year in Tamil Nadu (52,69,333), followed by Andhra Pradesh (31,37,697), Karnataka (25,31,763), Odisha (20,37,381) and West Bengal (18,73,076). In terms of total number of lightning flashes, the most happened in Tamil Nadu (58,17,180), followed by Andhra Pradesh (37,71,930), Odisha (33,03,076), Karnataka (29,70,192) and West Bengal (28,14,034). Please note that a lightning flash is a collection of pulses close in space and time that approximates the continuous ionized channels of a complete bolt of lightning. According to the newly released South Asia Lightening Report 2020, the state of Tamil Nadu witnessed 20,45,250 more total lightning bolts than the second ranked Andhra Pradesh. The geographical area of Tamil Nadu is about 1,30,058 square kilometre, which makes it the eleventh largest state in India. The state saw more lightning strikes in comparison to larger states like Maharashtra (geographical size of 3,07,713 km2) and Odisha (geographical size of 1,55,707 km2). Kindly consult chart-1.
The report has detected that Sri Lanka, South India and Northeast India had the highest pulse densities in 2020. The number of lightning pulses per square kilometre per year has been termed as pulse density.
The South Asia Lightning Report 2020 shows that most lightning strikes in the country took place in May, June, and September i.e. during the southwest monsoon season. The frequency of thunderbolts has increased between 2019 and 2020. In 2020, although the rainfall average across the country reached 109 percent (just 1 percentage point less than the 2019 average of 110 percent), the number of lightning strikes grew by almost 22.6 percent in comparison to 2019.
Most numbers of Dangerous Thunderstorm Alerts (DTAs) in 2020 were issued for Tamil Nadu (1,323), followed by Andhra Pradesh (868), West Bengal (852), Odisha (820) and Karnataka (718). Kindly note that the Dangerous Thunderstorm Alerts are extremely advanced severe weather warnings exclusive to Earth Networks. These patented alerts notify users severe weather is approaching up to 45 minutes before storms arrive. Most numbers of Dangerous Thunderstorm Alerts in 2020 were issued in the months of April (# of DTAs: 1,767), May (# of DTAs: 2,118), and June (# of DTAs: 1,092) i.e. monsoon season of 2020. In September 2020, the total number of DTAs issued were 882.
Although the farmers in India rely on southwest monsoon rainfall for agriculture, lightning and flooding pose major threats to them. Tracking month-wise DTAs is useful during monsoon season to ensure the safety of farmers who work in the fields during that span, says the report. The 2020 monsoon season kicked off with the highest amount of Dangerous Thunderstorm Alerts being issued in May (barring Sri Lanka) -- India (# of DTAs: 2,118), Bangladesh (# of DTAs: 254), and Sri Lanka (# of DTAs: 416).
In 2020, the Dangerous Thunderstorm Alert Density (DTA density i.e. DTAs per square kilometre) in the country was found to be comparatively high in the states of West Bengal, Kerala and Tamil Nadu.
The Northeastern region of India is a typical hotspot for lightning, besides Dangerous Thunderstorm Alerts. The South Asia Lightning Report 2020 states that "[d]uring the pre-monsoon season, India undergoes an increase in severe storms due to the heat that comes before the Monsoon onset and the increasing moisture that occurs as the country heads toward the monsoon. This happens in April, May, and June primarily and in the Northeastern part of the country. The strong storms are called “Nor’westers” because they develop in the hills of Northeast India and move from the Northwest to the Southeast. They produce severe weather with frequent lightning, hail, very strong wind gusts and heavy rain. They are very similar to the severe storms we have in the U.S. that form in the High Plains and charge across the central U.S. in the Spring." It further mentions that "India gets more lightning and severe storms in the pre-monsoon (late march to early June) because a very strong temperature contrast exists between the surface and the upper levels and the increase in surface moisture that begins at that time."
The report says that the Earth Networks’ lightning sensors are located in most states in India, and the ENGLN works closely with various disaster management authorities in states like Andhra Pradesh, West Bengal, Odisha, Karnataka, Bihar, Assam, and Kerala. The company offers comprehensive visualisation and alerting tools that enable India’s disaster management agencies to issue automatic warnings and estimate storm arrival times to help save lives and reduce property damage. At present, the Earth Networks works with various central and state agencies (such as Indian Armed Forces, Ministry of Earth Sciences, and North Eastern Space Applications Centre-NESAC), universities, and private industry sectors across the country.
Official data on lightning deaths
Data compiled by the Ministry of Statistics and Programme Implementation (MoSPI) from various official sources indicate that lightning was responsible for the most deaths among all natural extreme events in each of the years between 2015 and 2019.
Table 1: Number of deaths by type of natural extreme event
Source: Component 4: Extreme Events and Disasters, in EnviStats India 2021, Vol. 1: Environment Statistics, Ministry of Statistics and Programme Implementation, please click here and here to access
Table-1 shows that lightning caused 2,641 deaths in 2015, 3,315 deaths in 2016, 2,885 deaths in 2017, 2,357 deaths in 2018 and 2,876 deaths in 2019. The share of lightning deaths in total deaths caused by natural extreme events in India was 25.1 percent in 2015, 38.2 percent in 2016, 40.4 percent in 2017, 34.2 percent in 2018 and 35.3 percent in 2019. Therefore, advance warning about extreme weather events can save many lives.
Scientists predict that thunderstorms and lightning will become more frequent and more deadly in the coming years. As the Earth’s surface becomes warm (on account of global warming), the air above it also gets warm, which is then able to absorb more moisture. This phenomenon is correlated with more number of lightning strikes. So, with the rise in global temperature, the frequency of lightning strikes will increase. If the concentration of cloud condensation nuclei (CCN) in the atmosphere increases, then the number of lightning strikes rise. The concentration of CCN in the atmosphere becomes high during forest fires and rains. Public awareness about the safety guidelines on lightning strikes (please click here and here), which has been developed by the India Meteorological Department (IMD), can prevent human casualty.
Annual Lightning Report 2020-2021, India Meteorological Department, Ministry of Earth Sciences, Indian Institute of Tropical Meteorology, India Meteorological Society and World Vision India, please click here to access
Thunderstorm and Lightning: Tackling Weather Hazards, National Disaster Management Authority, Ministry of Home Affairs, please click here to access
IMD issuing guidelines on precautions to be taken before, during and after a thunderstorm, Vigyan Samachar: MoES News, released on 10th July, 2020, please click here to access
Thunderstorm & Lightning: Dos and Don’ts, IMD Nagpur, please click here to access
Transboundary Bengal hotspot for lightning strikes: Report -Jayanta Basu, Down to Earth, 23 July, 2021, please click here to access
Climate Change Will Make Lightnings More Frequent, Deadlier Over India, TheWire.in, 23 July, 2021, please click here to access
Explained: Here’s how lightning strikes, and why it kills -Amitabh Sinha, The Indian Express, 15 July, 2021, please click here to access
20 killed, 21 injured in various incidents related to lightning strikes across Rajasthan -Mohammed Iqbal, PTI/ The Hindu, 12 July, 2021, please click here to access
Lightning killed 18 elephants in Assam: report, The Hindu, 4 June, 2021, please click here to access
Explained: Can a single lightning flash kill 18 elephants? Science says yes, in various possible ways -Kabir Firaque, The Indian Express, 22 May, 2021, please click here to access
Image Courtesy: South Asia Lightning Report 2020