IMD warns of heavy rains across northwest region
Rainfall activity over northwestern India is likely to increase from Sunday and heavy to very heavy rainfall is expected at isolated places in the Western Himalayan region over the next two days.Updated: Aug 09, 2020 00:29 IST
India Meteorological Department (IMD) on Saturday issued an orange category warning, which means disaster management authorities should be prepared to avert any possible disasters, for parts of northwestern India for Sunday and Monday as the monsoon trough is likely to shift northwards and cause heavy to very heavy rain in Uttarakhand, Haryana, Chandigarh, Delhi, western Uttar Pradesh, eastern Rajasthan.
Rainfall activity over northwestern India is likely to increase from Sunday and heavy to very heavy rainfall is expected at isolated places in the Western Himalayan region over the next two days.
Extremely heavy rains continued on Friday and Saturday in Kerala, where a red category warning has been issued for the weekend. A red warning implies disaster management authorities need to act immediately to control or prevent any rain or flooding disaster. Heavy rains triggered a landslide in Kerala’s Idukki district on Friday and left at least 15 people dead.
Torrential rains triggered floods and landslides in the Western Ghats in Kerala in 2018 and 2019 and left hundreds dead. The entire Western Ghats mountain range, which stretches from Kerala to Gujarat, is extremely vulnerable to disasters because of its topography and increasing incidence of extreme rains linked to global warming.
National Weather Forecasting Centre senior scientist RK Jenamani said strong westerly and south-westerly winds from the Arabian Sea hit the Western Ghats perpendicularly. “The low-pressure area over the Bay of Bengal strengthened the monsoon winds. Monsoon is a large-scale system of winds and moisture surge. The west coast is definitely vulnerable but the incidence of extreme rain is increasing across the country in recent years.”
Devala in Tamil Nadu and Kerala’s Vadakara recorded 34 cm and 33 cm from Friday to Saturday.
IMD director general M Mohapatra said extremely heavy rains were likely to continue in many places in Kerala till Monday. “When the warm westerly winds hit the hills, the ghat areas there are uplifting that air. It is called orographic uplifting. The warm air condenses and forms clouds. The formation of convective clouds leads to extremely heavy rain,” he said. He added Kerala has been recording deficient monsoon rains over the long term but there has also been an increase in the incidence of extreme rainfall events.
A fresh low-pressure area is likely to form over north and adjoining west-central Bay of Bengal by Sunday. Under its influence, more rain is likely over east and adjoining parts of central India and heavy to very heavy rainfall in Odisha from Sunday to Tuesday and in Vidarbha and Chhattisgarh from Monday to Wednesday.
According to a Union earth sciences ministry report, there has been a significant rising trend in the frequency and intensity of extremely heavy rain events over central India from 1950 and a decreasing trend in the moderate rain events. Compared to the 1901–1975 period, rainfall has reduced by 1–5 mm/day during 1976–2015 over central parts of India (the core monsoon zone), Kerala, and extreme northeastern parts, it added.
An Indian Institute of Tropical Meteorology study published in Nature journal in 2017 said there has been a three-fold rise in extreme rains along the west coast and central India from 1950 to 2015.
“I cannot comment on each station, but overall studies have shown that incidence of extremely heavy rain along the west coast is increasing due to the impact of global warming,” said Mohapatra.
“Monsoon trough (line of low pressure) is likely to shift northward and will continue to pass close to Delhi NCR during evening of August 9 to 12. During this period south westerly winds from Arabian sea and easterly winds from Bay of Bengal will reach to Haryana, Delhi NCR and west UP in lower levels.A cyclonic circulation will also form and persist over Madhya Pradesh and adjoining Uttar Pradesh during the same period. Delhi is likely to get moderate category rain during the period,” said Kuldeep Shrivastava, head, Regional Weather Forecasting Centre.