Explained: As rain fury continues in North India, did IMD's forecasting fail?

North India, especially the capital, Delhi, and Himachal Pradesh are experiencing a very wet time – torrential rain has wreaked havoc, with some reports pegging the death toll in the region to be as high as 100. Delhi, on Monday, witnessed 153 mm of rain, the highest precipitation in a single day in July in 40 years, leading to waterlogged roads, flooded houses and the Yamuna river rising to dangerous levels. The hill state of Himachal Pradesh has received rainfall four times than normal for July till now, leading to landslides, more deaths and a scene of chaos and destruction. As the wet weather prevails, a question is being asked by many: Did the India Meteorological Department fail in providing timely warning for such weather? Does India need a better forecasting system? Rain fury in the North North India is still reeling from the torrential rainfall that has lashed the area since the weekend. Frightening visuals of landslides, bridges being swept away and vehicles washing away put on show just how bad the rains have been. Himachal Pradesh has received the major brunt of the rainfall – entire houses and buildings have been washed away owing to the heavy showers. Officials on Wednesday have pegged the death toll in the hill state at 31. An NDTV report has added that the loss of infrastructure in the state – shops washed away, roads damaged – is an estimated Rs 3,000-4,000 crore. [caption id=“attachment_12857092” align=“alignnone” width=“640”] Locals walk along the eroded riverbank damaged by the swollen Beas river following heavy monsoon rains, in Kullu. PTI[/caption] Himachal Pradesh’s chief minister Sukhvinder Singh Sukhu also tweeted earlier, “Nature’s fury has tragically claimed the lives of 17 persons besides causing extensive damage to the roads, power transformers, electric sub-stations and numerous water supply schemes by throwing normal life out of gear in various parts of the state and an initial estimate of loss ranging from Rs 3,000 crore to Rs 4,000 crore.” The situation also led to Prime Minister Narendra Modi speaking to ministers and officials and urging them to take action to ensure that all are safe and dry. Also read: IMD predicts El Nino for this year: How will it affect monsoon rains in India? In Delhi too, the rain has caused massive damage as it has already received 112 per cent more rainfall than the average so far in the current monsoon season that started on 1 June. The Yamuna river has risen to its highest recorded level in 10 years and is expected to rise even further, prompting officials to carry out evacuation of thousands and move them to makeshift accommodations in safer places. Saurabh Bharadwaj, the Arvind Kejriwal-led AAP government’s water minister said previously that over 2,700 tents have been pitched to ensure the people’s well-being. The rain fury in Delhi was so intense that even the homes of Delhi’s ministers, including Public Works Minister Atishi, were flooded. Schools and educational institutions have remained closed while offices have requested employees to work from home. [caption id=“attachment_12857112” align=“alignnone” width=“640”] Locals wade through a flooded bylane at Yamuna Bazar area, in New Delhi. PTI[/caption] Reason for heavy rainfall Even as the region struggles with the consequences of the torrential rain, experts tried to ascertain the cause of Mother Nature’s fury. The IMD said that the rain was due to the confluence of monsoon winds and the western disturbance. For the unaware, a western disturbance is a low-pressure system that originates in the Mediterranean Sea and moves eastward across Central Asia. As it travels across the region, it brings changes in weather patterns, particularly in Northern India, Pakistan, and Nepal. Speaking to India Today, IMD chief Mrutyunjay Mohapatra said, “It (heavy rain) is mainly because of the interaction with the western disturbance, which is moving across Northwest India, and strong monsoon winds approaching the same region. There is the confluence between two types of winds, and these two winds are hitting the western Himalayan region.” Incidentally, this same weather pattern was witnessed in 2013 when Uttarakhand witnessed heavy downpour, including the cloudburst in Kedarnath. [caption id=“attachment_12857122” align=“alignnone” width=“640”] Commuters move past a waterlogged road at Laxmi Bai Nagar after monsoon rain, in New Delhi. PTI[/caption] Questions over India’s weather prediction The torrential downpour has put the spotlight on the IMD and their forecasting systems. Many have said that as the country continues to witness severe rain each year it is time for India to upgrade and improve it. But what is the science behind India’s rainfall forecast? India, at present, depends on satellite data and computer models for weather prediction. The Indian Meteorological Department uses the INSAT series of satellites and supercomputers. Apart from this, IMD also partners with the Indian Space Research Organisation (ISRO) for ground-based observations from the Automatic Weather Stations (AWS), the Global Telecommunication System (GTS) that measure temperature, sunshine, wind direction, speed and humidity. Meanwhile, the Agro-meteorological Tower (AGROMET) and Doppler Weather Radar (DWR) systems augment the observations. An NDTV report also states that IMD uses Doppler radars to improve their efficiency in predictions. In fact, the weather agency has increased Doppler radars from 15 in 2013 to 37 in 2023 to ensure better forecasting. However, it is far from a perfect science and several variables are involved. For instance, Professor Roddam Narasimha, FRS, a distinguished aerospace scientist, told Rediff.com that rainfall is one of the hardest things to predict. “Temperature and wind can be predicted more easily than rainfall. Rainfall, as common experience suggests, is very spotty. It can be raining here in Malleshwaram, but not on the old Airport road in Bengaluru. So, in space and time it is very spotty. The last bit of physics required that tells us whether it is going to rain or not is very hard.” [caption id=“attachment_12857132” align=“alignnone” width=“640”] A man sits inside a flooded house at Yamuna Bazar area, in New Delhi. PTI[/caption] He further stated that “the best minds in India have not devoted their time to the study of monsoon and they have followed the fashions of the West”. Former Secretary of the Ministry of Earth Sciences, Madhavan Rajeevan Nair was also quoted as telling India Today, “The model we are using has a certain bias. It normally under-predicts heavier rainfall. It can predict light or moderate rain better if the rainfall is in the vicinity of 80 mm in 24 hours. So the model can only give an indication that heavy or very heavy rainfall is going to happen in certain areas.” Dr Parthasarathi Mukhopadhyay, deputy project director, Monsoon Mission at Indian Institute of Tropical Meteorology (IITM) has also said to India Today that the dynamic models are based on certain assumptions. “It has not been possible to incorporate all components of nature accurately in the dynamical models and that is the first reason why sometimes forecasts can go wrong.” The errors in forecasts can also crop up due to errors in the initial input given to the models. Moreover, climate change is making forecasting the annual monsoon more difficult. It’s important that India improves on its rain forecast; after all, it plays a decisive role in India’s economy, so much so that former President Pranab Mukherjee had once said, “Monsoon was India’s real finance minister.” With inputs from agencies