NEW DELHI – A potent and unusual combination of weather systems has been identified as the cause of the catastrophic rainfall, floods, and landslides that have ravaged northern India in recent weeks. A report by Down To Earth details how an abnormally high number of western disturbances during the monsoon season, coupled with a peculiar northward push of moisture-laden winds from the Arabian Sea, created a “concoction” of weather that has led to a rainfall catastrophe.
According to the analysis, the normal monsoon rains have been exacerbated by the frequent presence of western disturbances. These are non-monsoonal storms that typically originate over the Mediterranean region and bring winter and spring rainfall to the Indian subcontinent. However, data from the India Meteorological Department (IMD) shows that a staggering 17 such disturbances have affected the country since June 1, 2025—far exceeding the usual one to four occurrences during the monsoon period.
The high volume and intensity of the rainfall are evident in the data. From June 1 to September 4, 2025, Punjab recorded a 53% rainfall excess, Delhi 52%, and Himachal Pradesh 50%. The Union Territory of Ladakh experienced an astonishing 444% excess. These figures underscore the severity of the situation, which has resulted in widespread flash floods and riverine flooding.
The interaction of these western disturbances with low-pressure areas from the Bay of Bengal, which were pushed unusually northward by moisture-heavy winds from the Arabian Sea, is a key factor. Raghu Murtugudde, a retired professor at the Indian Institute of Technology, Bombay, stated that this northward movement is likely driven by “anomalous moisture-laden winds” from the Arabian Sea.
Experts believe that these abnormal weather patterns require further scientific investigation. Kieran Hunt, a research fellow at the University of Reading, UK, suggests that a new “flavor” of western disturbance, known as Potential Vorticity (PV) cut-off lows, may be responsible for their increased frequency during the monsoon. These systems can reach India without needing the subtropical jet stream, which is the usual carrier of western disturbances.
The report also links the delayed retreat of the subtropical jet stream a band of upper-atmosphere winds that carries western disturbances to the rapid warming of the Arctic region. This, in turn, is connected to a decrease in the temperature gradient between the equator and the North Pole, leading to greater instability in weather patterns.
The confluence of these regular and abnormal weather systems has created a perfect storm, with severe consequences for north India. The findings highlight the complex and evolving nature of weather patterns in the region and the urgent need for a deeper understanding of how climate change is intensifying such catastrophic events.