Extreme weather events have become more common in the recent years. Every year, around this time, similar news is reported from various parts of the country, underscoring the recurring and pervasive nature of these challenges during the monsoon season. Data from the IMD indicates that between 2014 & 2023, the frequency of heavy rainfall events has reduced considerably in Karnataka, Odisha and Andhra Pradesh in the last decade, while slowly rising in Madhya Pradesh, Gujarat, and Uttar Pradesh.
Recently, especially since the onset of the Southwest Monsoon in June 2024, several parts of India have been severely affected by torrential rains, leading to significant loss of life and widespread displacement. Emergency workers have been tirelessly rescuing stranded individuals in different parts of the country. Intense rainfall has caused extensive damage in different parts of the Himalayas. The capital Delhi has experienced intense rainfall, resulting in fatalities and infrastructure damage. In Uttarakhand, a devastating cloudburst led to loss of life and further complications due to bad weather. Similarly, Kerala faced deadly landslides triggered by unexpected heavy rain, while incessant rainfall in the northeast has caused severe flooding, displaced thousands and resulted in numerous casualties.
Beyond the immediate loss of life and displacement, these torrential rains have a profound effect on agricultural production and the overall economy. A significant portion of agricultural output in India occurs during the southwest summer monsoon season, with most regions receiving over 70-80% of their annual rainfall during this time. The agricultural outcomes are closely linked to the monsoon, with even a 1% change in the annual monsoon rainfall causing a 0.34% change in India’s annual agricultural GDP. Given that agricultural production constitutes nearly 18% of India’s total GDP, the monsoon’s impact is both significant and multifaceted, affecting economic stability and livelihoods across the nation.
Heavy Rainfall & Extreme Weather events becoming more common
Extreme weather events have become more common in recent years. Around this time every year, similar news is reported from various parts of the country, underscoring the recurring and pervasive nature of these challenges during the monsoon season.
The India Meteorological Department (IMD) classifies rainfall events as follows:
| Category | Range |
| Very Light to Light Rainfall | 0.1 – 15.5mm |
| Moderate Rainfall | 15.6 – 64.4 mm |
| Heavy Rain | 64.5 – 115.5mm |
| Very Heavy Rain | 115.6 – 204.4mm |
| Extremely Heavy Rain | >= 204.5mm |
These events are monitored through the 5,896 District level Rainfall Monitoring Scheme stations across India as of 2023. Additionally, India also has 1,382 Automatic Rain Gauges.
In this story, we look at the trends in the state-wise heavy, very heavy, and extremely heavy rainfall events recorded in the last decade. The data is sourced from Factly’s Dataful. For this story, we have considered only sixteen states which have reported relatively higher numbers of such events. These include the five states in the southern peninsular region, states in the western part of India, Madhya Pradesh, Bihar, Jharkhand, Uttar Pradesh, Assam, Meghalaya, Odisha and West Bengal.
Karnataka recorded decline in heavy rainfall events
Karnataka, Odisha, and Bihar have recorded the highest number of heavy rainfall events (64.5 to 115.5 mm) between 2014 and 2023. Each of these states has recorded an average of 1250 to 1370 heavy rainfall events each year. Maharashtra also has recorded an average of 1050 heavy rainfall events during this period.
The number of heavy rainfall events recorded in Karnataka and Andhra Pradesh has declined since 2014 & 2015. Meanwhile, Bihar, Madhya Pradesh, Maharashtra, and Tamil Nadu saw a decline in the number of heavy rainfall events in the last two to three years.
Karnataka, Odisha, and Maharashtra recorded an average of 340 occurrences of very heavy rainfall events (115.6 to 204.4mm) in the last decade. However, the frequency of such events has dropped considerably in Karnataka, Odisha and Andhra Pradesh in the last decade, while slowly rising in Madhya Pradesh, Gujarat, and Uttar Pradesh.
Extremely Heavy Rainfall events (>=204.5mm) have increased considerably in Madhya Pradesh since 2017. The occurrence of such events has also increased considerably in Telangana since 2019. Just like in the case of other categories, Karnataka has seen a decline in extremely heavy rainfall events too.
Meghalaya which recorded an average of 134 heavy rainfall events and 71 very heavy rainfall events since 2014, recorded an average of 55 extremely heavy rainfall events, higher than all other states except Odisha which recorded an average of 61 such events.
More very heavy and extremely heavy rainfall events are being reported in July
Data from IMD on the occurrences of very heavy and extremely heavy rainfall events during the monsoon months reveals that both categories of events have increased considerably over the years in the months of June and July while declining in the months of August and September. This can be because of the increasing number of heavy rainfall events in the month of October, mainly due to the delayed withdrawal of the southwest monsoon. Such unseasonal downpour significantly impacts the agricultural production in the country.
Studies highlight how such events are going to increase in the coming years
In short, rainfall events have become more erratic over the years. Multiple studies have pointed out that such events are only going to increase in the coming years. The government’s study on the assessment of climate change over the Indian region reveals that the southwest monsoons in the country have declined by around 6% from 1951 to 2015, with notable decreases over the Indo-Gangetic Plains and the Western Ghats. It also noted that there has been a shift in recent times towards more frequent dry spells and more intense wet spells during the monsoon season. Another study revealed that peninsular India and northwest India will witness an increase in the intensity or magnitude of extreme rainfall in the coming years.
These studies also note that the significant changes in the frequency of hydro-climate extreme events can have a considerable impact on agriculture, health, and other socio-economic conditions of the society and call for designing appropriate basin-wise climate adaptation and mitigation strategies, including water and emergency services policies to minimize risk due to extremes in the basins.
