A new study analysed deaths caused by lightning in Bihar, here’s what it found

The study identified gender-segregated data for 1,577 deaths. Out of these 1,577 deaths, 1,131 (71 per cent) were men. Rural men between the age groups of 11-15 years and 41-45 years were particularly vulnerable as per the study by IMD scientists.

On average, there were 271 human deaths and 57.2 injuries due to lightning strikes each year in Bihar during the six-year study period. The state’s annual casualty rate per million of 2.65 was higher than the national average of 2.55, the study said. The period between May to September was the peak for lightning strikes with June and July accounting for 58.8 per cent of lightning-linked deaths.

Researchers explained that lightning strikes reach a record high in June and July with the monsoonal current setting in, mainly due to the interplay of easterly and westerly winds.

Cloud-to-ground lightning strikes claim thousands of lives each year and Bihar ranks among the top three most-affected states in terms of lightning-linked casualties along with Madhya Pradesh and Uttar Pradesh, data shared by the Earth Sciences Ministry in Parliament shows.

The plains area is prone to thunderstorms and lightning activity as warm, dry air from north-west India converges with moist air emanating from the Bay of Bengal, creating conditions that are favourable for the formation of deep convective clouds, the study said.

The eastern state, much of which lies in the Indo-Gangetic plains, spends Rs 12-15 crore each year on compensation payouts to families of those killed or injured by lightning strikes, as per the study. The state’s disaster budget is approximately Rs 300 crore, with a significant amount spent on ex gratia payments, the study added.

One of the more nuanced aspects of vulnerabilities found during the study was the higher impact of lightning strikes in districts with higher population density, said lead author Anand Shankar, an IMD scientist from the Patna Meteorological Centre.

“In North West Bihar, the lightning strikes are lower but casualties are higher. These parts of Bihar are not urbanised and may be having poor shelter density around farm areas. Socio-economic factors play an important role in mitigating the impact of such natural hazards,” he said. Shankar added that the timing of the lightning strikes and the corresponding casualties are in line with global findings. This is because most thunderstorm activity takes place in the afternoon, he said.

The study’s co-author Vivek Sinha, a senior scientist from IMD Delhi, said that the threat potential of lightning strikes is not uniform. Topography, elevation, and local meteorological factors determine the spatial distribution of lightning strikes.

A higher lightning frequency is seen in the eastern region owing to higher moisture incursion, the study said.

Sinha said that assessing vulnerability and hotspots is important for policymakers and to design mitigation measures. “Awareness has to increase. This kind of vulnerability mapping can provide a template to change the operational side of disaster management,” Sinha said.