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Rains continued to lash large parts of Himachal Pradesh, Delhi, Punjab, Haryana, and Chandigarh for the third straight day on Monday, 10 July, affecting normal life in the region. Schools remained shut in the national capital due to heavy rains.
Over the weekend, waterlogging, landslides, and flash floods were reported from states in north India. On Sunday, the Central Water Commission (CWC) said that the water level in the Yamuna river in Delhi is going up and is expected to breach the danger mark of 205.33 metres on Tuesday, 11 July.
However, Delhi Chief Minister Arvind Kejriwal assured people that experts have said a flood situation might not arise in the national capital.
Vehicles move through a waterlogged road after heavy monsoon rains at Tilak Bridge, in New Delhi, on Sunday, 9 July. Qui
(Photo: PTI)
But why has the region been receiving excessive rainfall? Does climate change have any role to play in this? The Quint answers these questions.
A Look at Some Statistics
According to the India Meteorological Department (IMD), from a 10 percent deficiency in rainfall till the end of June, the monsoon's surge over the west coast and parts of northern India in the past week has led to a 2 percent excess rainfall over the country on 9 July.
While the eastern and northeastern region has recorded a deficiency of 17 percent (375.3 mm against a normal of 454 mm), north India has witnessed 59 percent excess rainfall (199.7 mm against a normal of 125.5 percent), as per the latest IMD data.
Central India has recorded 264.9 mm rainfall against a normal of 255.1 mm, which is an excess of 4 percent. The rainfall deficiency in south India has reduced from 45 percent to 23 percent.
As a whole, Himachal Pradesh recorded 103.8 mm rainfall between Saturday and Sunday morning against a normal of 8 mm, which makes it 1,193 percent excess rainfall.
Similarly, Punjab recorded 57.5 mm against the normal of 4.6 mm rainfall, making it 1,151 percent excess for the day.
But What Is Behind the Excess Rainfall?
Experts have attributed the deluge to the combination of two weather systems.
"The heavy rainfall is due to an interaction between a western disturbance and the monsoon," M Mohapatra, Director General of India Meteorological Department (IMD), explained to The Quint.
He further elaborated that there is a merging of a trough (an elongated area of relatively low pressure) extending from Rajasthan to north Arabian Sea linked to a western disturbance and winds from Bay of Bengal towards the north, centred around Jammu & Kashmir on Saturday and around Himachal Pradesh on Sunday.
As a result, this brought heavy to very heavy rainfall over Jammu and Kashmir, north Punjab and Haryana, Uttarakhand, and Himachal Pradesh, Mohapatra said.
Similar Occurrence Led to Uttarakhand Floods
Mohapatra went on to explain that the merging of two weather systems is not uncommon. In fact, they have been associated with extreme weather events, especially in the hills of northwest India.
"In 2013, around mid-June, a western disturbance absorbed moisture towards the north from a low-pressure system coming in from the Bay of Bengal. This caused extremely heavy downpour in Uttarakhand, including the cloudburst at Kedarnath," he said.
But what exactly causes rainfall when two weather system merges?
Mohaptara told news agency PTI that the mountains get a lot of rain from a confluence of such two weather system as the winds hit the hills and rise, causing heavy precipitation (rainfall).
Does Climate Change Have Anything To Do With It?
Roxy Mathew Koll, a climate scientist at Indian Institute of Tropical Meteorology, told Hindustan Times:
"In a changing climate, we see that hilly areas and surroundings - whether it's the Himalayan foothills or the Western Ghats - are particularly susceptible to heavy rains and landslides. Due to global warming, there's extra moisture, and the hills stop this moisture flow and lift it, which comes down as heavy rains."
"Some of the regions over India where extreme rains have increased are such places where the rains happen due to orographic lifting," he told the newspaper.
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