NEW DELHI: The deluge in north India over the past two days resulted from a deadly confluence of two systems – the monsoon winds and a western disturbance – similar to the interaction of two systems that led to the deadly Uttarakhand flooding in 2013. Such interactions are increasingly likely to cause extreme rain and flooding in a warming world, warn experts.
Meanwhile, helped by the heavy downpours in the north, the nationwide monsoon deficit was wiped out and cumulative rainfall in the season recorded a surplus of 2% for the first time since June 1. Over the past two days, two weather systems have been active over north India.
“There was a trough extending from Rajasthan to north Arabian Sea associated with a western disturbance. At the same time, due to strong monsoon conditions, the winds from Bay of Bengal were also reaching the north. There was a confluence of these two systems, centred around Jammu & Kashmir on Saturday and around Himachal Pradesh on Sunday. These areas got moisture from both Arabian Sea and Bay of Bengal, resulting in very heavy showers,” said IMD chief Mrutyunjay Mohapatra.
Such interactions between two weather systems aren’t uncommon and have been associated with extreme weather events, particularly in the hills of northwest India.
The flooding and landslides killed over 5K people, displaced over 5L
In mid-June of 2013, a western disturbance sucked moisture towards the north from a low-pressure system coming in from the Bay of Bengal. This not only resulted in the monsoon covering the entire country in record time (by June 16) but also caused cataclysmic downpours in Uttarakhand, including the cloudburst at Kedarnath. The flooding and landslides cause by that deluge killed over 5,000 people and displaced over 5,00,000, according to reports.
“The mountains get a lot of rain from such two-system confluences because the winds hit the hills and rise, causing heavy precipitation,” Mohapatra said. Kieran M R Huntfrom the UK’s University of Reading, who was the lead author of a study on such two-weather interactions in India, told TOI that the intensity of rainfall caused by these confluences could increase in a warming world.
“It is hard to say whether the frequency (of such interactions) will go up or down because there’s no clear trend. We can be fairly certain, though, that these interactions, when they do happen, will be increasingly linked with extreme rainfall and flooding,” Hunt said.


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