Cherrapunji records 3rd highest rainfall over 24 hours in 122 years
Abundant moisture from the Bay of Bengal and the Arabian Sea hit the Eastern Himalayas and brought extremely heavy rain (over 20 cm) to parts of Meghalaya and Assam
Cherrapunji in Meghalaya’s East Khasi Hills district recorded 97 cm rainfall over 24 hours on Friday, the third-highest quantum of rainfall recorded there in the last 122 years. The highest rainfall of 156.3 cm was recorded in Cherrapunji on June 16, 1995.
Mawsynram, which receives the highest rainfall in India, also in East Khasi Hills recorded 71 cm, the fifth-highest rainfall for 24 hours, on June 15. The highest rainfall record for Mawsynram is 94.5 cm (June 7, 1966). Several stations in the East Khasi Hills have registered rainfall records this week.
India Meteorological Department (IMD) is trying to document the rain recorded every hour to verify if the rainfall events can be categorised as cloudbursts. If 10 cm rainfall is received in one hour, the event is termed cloudburst.
Abundant moisture from the Bay of Bengal and the Arabian Sea has hit the Eastern Himalayas and brought extremely heavy rain (over 20 cm) to parts of Meghalaya and Assam.
IMD scientist RK Jenamani said southerly and south-westerly winds have been hitting the Eastern Himalayas for the past week. “Copious amounts of moisture from Arabian Sea and Bay of Bengal are landing up in that region. There is orography which can cause rain. There are very strong winds also and Cherrapunji is on the windward side,” he said.
Jenamani said extremely heavy rains can be expected for the next two days also. “But I think the peak rainfall period is over. From June 21, we are expecting rainfall activity to spread eastwards covering Bihar, West Bengal, etc.”
Skymet Weather vice president (climate change and meteorology) Mahesh Palawat said apart from an intense monsoon spell over the northeast, there are other reasons for the record-breaking rain. “There is a trough extending from northern plains up to Nagaland. There is a lot of moisture feeding that area from the Bay of Bengal. The remnants of a western disturbance are also reaching Assam and Meghalaya. In the southern parts of northeast India like Manipur, Tripura, and Mizoram such obstruction which can hold the moisture is not there so very heavy rain is not recorded there.”
There is a red category warning for Assam and Meghalaya for Friday and Saturday for extremely heavy rain. A trough at mean sea level is running from northwest Uttar Pradesh to Manipur across Bihar, Sub-Himalayan West Bengal, Sikkim, and Assam. “Moisture incursion is very likely to continue due to strong lower-level southerly/southwesterly winds from the Bay of Bengal to northeast India during June 17 to 20,” IMD said on Friday.
Under its influence, widespread rainfall accompanied by thunderstorms, lightning, and heavy to very heavy with extremely heavy rainfall is likely to continue over the northeastern states from Friday to Monday. The rainfall intensity is expected to decrease thereafter.
Overall, monsoon rains have also picked up even as there was a 32% rain deficiency on June 15. The deficiency was reduced to 18% on Friday.
The monsoon has advanced into the remaining parts of Sub-Himalayan West Bengal and parts of Bihar. The northern limit of the monsoon is now passing through Porbandar, Bhavnagar, Khandwa, Gondia, Durg, Bhawanipatna and Kalingapatnam.
IMD said conditions are favourable for further advance of monsoon into Madhya Pradesh, remaining parts of Vidarbha, Andhra Pradesh, and West central and northwest Bay of Bengal, parts of Chhattisgarh and Odisha, Gangetic West Bengal, Jharkhand, and Bihar during the next three days.