Fatal thunderstorms outcome of atmospheric cocktail, say experts

Hindustan Times

23-05-2025

At least 59 people in two states died due to incidents connected with a thunderstorm that ripped through swathes of northern India late on Wednesday, officials said on Thursday.
Meteorologists studying the storm said the system was the product of a complex atmospheric cocktail—multiple cyclonic circulations, abundant moisture from two seas on either side of the subcontinent, and extreme daytime heating—all supercharged by unusual persistence of the winter weather system known as Western Disturbances that should have retreated by now.
The phenomenon appears linked to unusual weather continents away—record heat in the Arctic Circle that is displacing cold air southward, triggering unseasonable cold across locations such as the US Eastern Seaboard.
This disruption echoes similar unusual shifts in a key weather system impacting India at present.
M Rajeevan, the former secretary of the ministry of earth sciences said western disturbances—Mediterranean-origin cyclones that normally impact India in winter before moving to northern latitudes during summer — have persisted well into summer.
'You expect western disturbances to move north of the Indian region in April, May, June months. In some years we are seeing that their impact is continuing in summer which is not good for the monsoon,' Rajeevan said.
'There are some studies which are suggesting that the active western disturbance season is shifting in recent years and studies that show reduced arctic sea ice can affect mid-latitude circulation and monsoon extremes,' he added.
Rajeevan's assessment of what is happening in India is similar to developments thousands of kilometres away. Parts of Iceland logged near-record temperatures of 27°C in the Arctic Circle, while western Greenland hit 19.9°C, well above average for the time of year.
Both phenomena, experts say, are driven by Arctic warming that displaces cold air southward—the same atmospheric disruption that is pushing western disturbances into India.
But Wednesday's storm also emerged from a perfect confluence of other atmospheric conditions. 'There was a cyclonic circulation and a trough which was impacting the entire northern region. Adding to this was ample moisture from the Bay of Bengal and Arabian Sea, and extremely high day temperatures. Hence, there is atmospheric instability,' Rajeevan explained.
The atmospheric instability, he said, manifested 'like bubbles, which can bring a lot of rain and thunderstorms'. The occurrence of so many such systems is 'somewhat unusual though not impossible,' Rajeevan added, calling for a close watch on whether these factors can impact progress of monsoon.
To be sure, IMD officials stated that there was no active western disturbance over northwest India on Wednesday.
But another expert made a more nuanced assessment. Mahesh Palawat, vice president at Skymet said these cyclonic circulations triggering thunderstorms over NW India are indeed a result of mild western disturbances seen as a trough over the region.
A cyclonic circulation is present over southern parts of Punjab, which is expected to cause mild dust storm spells in the evening or night time and thunderstorm to rain over most parts of northwest India till May 27, he added. 'Due to this cyclonic circulation, a trough extends from south Punjab to northeast India across south Haryana and north Madhya Pradesh. Delhi-NCR is in the vicinity of this trough. Thunderclouds develop due to moisture, leading to widespread thunderstorm and dust storm activities,' he said.
On Friday and Saturday, mild dust storm activity is likely across northwest India, with thunderstorm and rain likely from May 25 to 27. 'This will lead to a drop in temperature in the region again,' he said.
Uttar Pradesh, especially West UP, bore the brunt of the severe weather.
The deaths resulted from a deadly mix of weather-related hazards: lightning strikes claimed multiple lives, including a 65-year-old man in Saharanpur's Khajuri village and a six-year-old girl in Sonbhadra. Structural collapses killed several others, including an 80-year-old woman killed when a wall fell on her in Firozabad's Mogra village and a 26-year-old man crushed by an under-construction wall in Kannauj. Falling trees and infrastructure added to the toll—a constable in Bijnor died when his motorcycle collided with a storm-felled tree, while a heavy metal hoarding structure crushed a 44-year-old man at Jhansi railway station.
The storm's ferocity was most evident in Delhi, where wind speeds reached 79 km/hr at Safdarjung, 78 km/hr at Pragati Maidan, and 74 km/hr at Palam—velocities equivalent to a cyclonic storm by Indian meteorological classifications. Temperatures plummeted from 37°C to 23°C in just one hour at Palam airport, while rainfall aggregated 13.5mm in Mayur Vihar and 12.1mm at Safdarjung.
The extreme weather paralysed the capital between 8:00 and 8:30 pm Wednesday. At least 12 flights were diverted from Indira Gandhi International Airport, with over 50 delays reported. Delhi Metro services on the Red, Yellow, and Pink lines were disrupted after damage to overhead equipment, whilst hailstorms lashed parts of west, central, southeast and east Delhi.
Meanwhile, a low-pressure area over the east-central Arabian Sea is expected to intensify into a depression by Friday evening, potentially triggering early monsoon onset over Kerala—2-3 days ahead of the normal June 1 date.
But Rajeevan warned that the persistence of western disturbances could disrupt the monsoon's crucial northward progression. Combined with reduced winter snowfall in recent years, he said these shifts suggest fundamental changes in atmospheric circulation patterns.
'These developments should be tracked,' Rajeevan said, noting that continued western disturbance activity 'will not allow monsoon to progress properly.'
Wednesday's deadly storm serves as a stark reminder of how the climate crisis and distant Arctic warming can trigger extreme weather thousands of kilometres away, reshaping India's weather landscape in ways that could have far-reaching implications for agriculture, urban infrastructure, and the monsoon system that sustains hundreds of millions of lives.