Excess March rainfall: What it means for COVID-19 outbreak

The country recorded 77 per cent more rain than normal between March 1 and March 19, 2020

By Akshit Sangomla
Published: Monday 23 March 2020

Excessive rainfall in March 2020 — accompanied by thunder, hail and lightning — severely damaged crops, affecting farmers across the country.

The irregular weather patterns come close on the heels of an economic quarantine, itself the fallout of a worldwide pandemic caused by the COVID-19 disease outbreak.

The country recorded 77 per cent more rain than normal between March 1 and March 19, 2020, according to India Meteorological Department data.

There was large excess rainfall — more than 60 per cent than normal — recorded in 381 districts, 57 per cent of all districts in India.

Farmers suffered severe losses from the unseasonal rain and hail, with four lakh hectares of farmland damaged across the country, according to media reports.

Around 650,000 farmers in Uttar Pradesh suffered estimated economic losses up to Rs 255 crore, according to Skymet Weather, a private weather forecasting agency based out of Noida.

The distribution of rainfall throughout the country was uneven as most of it was concentrated in 13 states and Union territories in the north, central and east central regions.

Uttar Pradesh and Delhi recorded 698 per cent and 621 per cent excess rain respectively.

Bihar received nine times the normal rain it usually receives at this time period, while Jharkhand received eight times more in the same period.

Almost all districts in these states recorded large excess rainfall.

In Uttar Pradesh, all districts, barring one, received large excess rain. Chhattisgarh similarly received large excess rainfall in 25 of its 27 districts.

Jharkhand, Bihar, Punjab, Uttarakhand and Haryana also witnessed large excess rain in most of their districts.

States in the North East, however, received next to no rain, with Arunachal Pradesh, Manipur, Mizoram and Tripura recording large deficits of rainfall at 68, 77, 99 and 84 per cent, respectively.

Assam and Nagaland were also not far behind, with 48 and 50 per cent deficit rainfall, respectively.

Only Meghalaya and Sikkim, known to naturally receive more rainfall, recorded normal rainfall in March till date.

Goa remained the only state in the country to receive no rainfall. The union territories of Daman and Diu, Dadra and Nagar Haveli and Puducherry did not receive any rain either.

The southern peninsula received moderately high rain, with Tamil Nadu receiving next to no rain, an 87 per cent deficit.

Change in weather conditions

The copious amount of rainfall in March also meant cooler than normal temperatures in these regions, delaying the onset of summer.

An extended winter season in 2019 had meant a sudden jump from cold to extremely warm temperatures.

These weather conditions hold significance amid the ongoing COVID-19 pandemic.

Experts so far remain inconclusive about the direct impact of temperature on the spread of the novel coronavirus (SARS-CoV-2).

If the virus thrives in cooler temperatures, the districts that received large excess rain provide decent conditions for the virus to spread.

Some research papers, however, suggested high humidity and temperatures slow the spread of the virus, though these papers were not peer reviewed.

Scientists warned that the virus spread faster in countries lying in the southern hemisphere, like Australia, set for cooler temperatures in the winter season.

This warning, however, does not come with a detailed study of how weather affects SARS-CoV-2.

It is based on the behaviour of other viruses, human behaviour (people mostly huddle together during wintertime) and reduced human immunity to viruses during this period.

A new study launched by physicists at the University of Utah tries to answer the question of how the disease would fare in warm and humid conditions.

Saveez Saffarian and Michael Vershinin, the physicists leading the study, received a $200,000 grant from the United States National Science Foundation.

The study will check how the outer protective shell of the virus behaves under different environmental conditions. It also analyses the dynamics of the droplets through which the disease spreads.

Dummy versions of the shells of the virus — with inner genomes removed and made with sequenced genomes — are being used.

The behaviour of the shell and droplets under different conditions would reveal how the virus spreads the infection.

“We're making a faithful replica of the virus packaging that holds everything together,” Vershinin said in a statement on March 18.

“The idea is to figure out what makes this virus fall apart, what makes it tick and what makes it die,” he added.

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