Indian Monsoon 2024 breaks 5-Year Record for Very-Heavy and Extremely-Heavy Rainfall Events

India witnessed a significant increase in the number of very-heavy and extremely-heavy rainfall events, the highest in the last five years, during the 2024 monsoon season. In a clear indication of a sharp increase in extreme rain-related events in India, a report published by the India Meteorological Department (IMD) revealed that there were 2,632 instances of very-heavy rainfall and 473 instances of extremely-heavy rainfall during the Southwest Monsoon season. According to the IMD data, the month of September appeared to be the most affected in terms of the high number of very-heavy rainfall events, in comparison to the last five years. 

Very-heavy rainfall refers to rain exceeding 115.6 mm in a 24-hour period, while extremely-heavy rainfall is more than 204.4 mm in the same time frame. 

Additionally, the report also highlighted that the “core monsoon area” (a region that receives the bulk of monsoon rainfall) experienced excess rainfall, meaning it received more than the average expected rainfall. 

The rise in extreme rainfall events in India is increasingly being linked to climate change. Warmer atmospheric temperatures allow more moisture to be retained, intensifying monsoon rainfall patterns. As a result, the country has seen a significant increase in very-heavy and extremely-heavy rainfall events, leading to more frequent floods, landslides, and damage to infrastructure. This erratic and uneven distribution of rainfall—excessive in some areas while deficient in others—reflects the growing influence of climate change on India’s monsoon system, posing challenges to agriculture, water management, and disaster preparedness.

Anupam Kashyapi, former head of weather forecasting, IMD, was quoted as saying by The Indian Express, “La Nina, the cold ocean current in the Pacific, was active from August onwards, leading to robust rainfall. Also, every year, the monsoon comes with its inter-annual variability, which, this year, was reflected in the increase in the number of extreme events. However, climate change can also be a reason…” 

In 2023, which was officially classified as a drought year due to overall below-average rainfall, India still experienced 2,321 very-heavy rainfall events and 421 extremely-heavy rainfall events. Despite the drought conditions in some regions, these figures highlight the uneven distribution of rainfall, with certain areas experiencing intense rain events even as the country faced a rainfall deficit overall. This suggests a rise in the frequency of extreme weather patterns, where heavy rainfall events can occur even in years marked by drought.

The IMD report also revealed that during the 2024 Southwest Monsoon (June-September), India received 108% of its long period average (LPA), marking an above-normal monsoon. Rainfall in different regions varied: Northwest India (107%), Central India (119%), South Peninsula (114%), and Northeast India (86%). The monsoon core zone, crucial for rain-fed agriculture, recorded 122% of LPA. Of India’s 36 meteorological subdivisions, 9% of the area received large excess rainfall, 26% saw excess rainfall, 54% received normal rainfall, and 11% (including Arunachal Pradesh, Punjab, J&K, and Ladakh) experienced deficient rainfall.

The monsoon season in India officially begins on June 1 and concludes on September 30. However, the retreating monsoon, which refers to the gradual withdrawal of monsoon winds, often extends beyond this official end date. Some regions continue to receive rainfall as the monsoon withdraws, particularly in parts of southern India and the eastern coast, which may experience lingering showers even after September well into October.

References:

https://internal.imd.gov.in/press_release/20241001_pr_3310.pdf

https://indianexpress.com/article/india/monsoon-2024-reports-extreme-rainfall-years-9606493

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