The monsoon season has currently demonstrated its destructive power in Gujarat, bringing not just ordinary rainfall, but true chaos. In some areas, over 400 mm of precipitation was recorded in just 14 hours. Chikhli (Navsari) received 451 mm, Dholka (Ahmedabad) received 440 mm, Kergam received 431 mm, Umarpada (Surat) received 405 mm, and Umargaon (Valsad) received 365 mm.
Rivers overflowed, roads were flooded, and agricultural lands were submerged by water. The lives of the population have been disrupted because these rains were significantly more intense and catastrophic than expected from a normal monsoon. A discussion has arisen among meteorologists and social media users. Several months ago, many forecasters, including local and American scientists, predicted drought based on the strength of El Niño.
However, reality turned out to be the opposite: the monsoon brought not only normal but also excessive rainfall. This raises the question of why scientists underestimated the Pacific Decadal Oscillation (PDO)? PDO is a pattern of long-term changes in sea surface temperature in the Pacific Ocean, which manifests in a decadal, or 20–30 year, cycle. It is similar to El Niño and La Niña (ENSO), but its time period is much longer. While ENSO lasts from a few months to two years, PDO maintains its influence for decades.
PDO has two main phases: positive and negative. During the positive phase, waters near the coast of the northeastern Pacific warm up, while the central part cools down. In the negative phase, the opposite occurs: the northeastern coast becomes cold, and the central area remains relatively warm. Currently, in 2026, PDO is in a very strong negative phase, with index values fluctuating between -1.3 and -1.6.
This cycle affects not only sea temperature but also atmospheric pressure, wind direction, and overall global atmospheric circulation, having a deep connection with the Indian monsoon. Scientific studies show that the negative phase of PDO strengthens the Indian summer monsoon, improving the flow of moist air over India. This leads to the strengthening of the monsoon depression due to the influx of moisture from the western Pacific and the Indian Ocean, ultimately causing heavier, and in some places, extremely severe rainfall. Conversely, the positive phase of PDO often triggers weak monsoons and drought in India. In recent decades, periods of negative PDO phases have been accompanied by increased rainfall in India, with this influence being particularly felt in the western parts of India, such as Gujarat, as the moisture coming from the Arabian Sea is directly subject to the PDO pattern.
This year, scientists focused primarily on ENSO, despite the weakening of El Niño and concerns about La Niña; many models showed a deficit of rainfall. However, the powerful negative phase of PDO overshadowed the influence of ENSO, explaining the inaccuracy of many forecasts. The reasons for underestimating PDO are manifold. The main reason is that PDO is a decadal cycle, whereas meteorological forecasts are mainly oriented toward a seasonal scale. Short-term factors, such as ENSO, are easily incorporated into models, while long-term drivers like PDO are complex to fully understand and integrate into models.
Furthermore, the variability of PDO is underestimated in many models. Climate models still cannot perfectly simulate decadal variability, leading forecasters to underestimate the strength of PDO. A third factor is the intersection with climate change. Rising sea temperatures due to global warming cause changes in PDO patterns. Some studies suggest that warming may intensify the negative phase of PDO, but models have not yet been able to fully grasp this interaction.
The heavy rains in Gujarat are the result not of a single system, but of large-scale climatic processes. The negative phase of PDO helped shift the monsoon depression southward, ensuring a constant inflow of moisture from the Arabian Sea. Local factors, such as topography and urban flooding, exacerbated the situation. Areas like Chikhli and Umargaon are geographically situated such that the proximity of mountains and the sea contributes to intense precipitation. Rainfall exceeding 400 mm in 24 hours is not typical, but an extreme event that is becoming more frequent in the era of climate change.
This incident serves as a reminder of the need to consider not only ENSO but also other driving forces, such as the Indian Ocean Dipole (IOD) and the Atlantic Multidecadal Oscillation (AMO). It is necessary to strengthen multi-decadal forecasting systems. Farmers, administrations, and the public should be aware of these large patterns. If PDO remains in a negative phase, there is a continued probability of heavy rains and floods in several regions of India in the coming years, and the intensity of extreme events is increasing due to climate change. The disaster in Gujarat has once again proven that nature cannot be viewed from only one perspective.
The monsoon brought record rainfall to Gujarat this season. In the Umbargaon area of Valsad district, between 6 am on July 22 and 6 am on July 23, 906 mm of rain was recorded. This figure exceeds the average annual rainfall in Delhi, which is 700–800 mm. Thus, Umbargaon received as much rain in a single day as Delhi receives in an entire year.
Due to such heavy rainfall, conditions similar to flooding arose in several areas of South Gujarat. Roads, residential houses, shops, and railway tracks were submerged. In many places, water entered residents' homes, completely paralyzing daily life. The administration conducted relief and rescue operations, evacuating about 1200 people to safe locations.
According to the Meteorological Department (IMD), the cause of such intense rains was moist air masses coming from the Arabian Sea and the intensification of the southwest monsoon. The impact of the rains was not limited to Umbargaon; in Valsad and neighboring areas, prolonged hours were accompanied by heavy precipitation.
The water level in rivers and streams rose sharply. In many places, water overflowed onto roads, hindering people's movement. Some vehicles got stuck in the middle of the highways. The flooding of railway tracks also affected train movement. The administration, along with NDRF teams and other rescue groups, worked continuously to provide assistance and transport people to safe zones. According to the State Emergency Operations Centre (SEOC), the maximum rainfall in Umbargaon was 906 mm.
Additionally, 731 mm was recorded in Kaprada, 643 mm in Nanapond, 499 mm in Dharmpur, 448 mm in Pardhi, 435 mm in Vansad, 413 mm in Vapi, and 403 mm in the city of Valsad itself. 378 mm was registered in Dolvan of Tapi district, and 369 mm in Vaghi of Dang district.
These data clearly show that a very large amount of rainfall fell in various parts of South Gujarat in one day. IMD notes that the southwest monsoon remains very strong over Gujarat, and the constant influx of moist air from the Arabian Sea contributes to this. Furthermore, the weather system over West India remained in one region for a long time, causing clouds to continuously pour rain in the same zone, leading to heavy precipitation in just a few hours.
When such heavy rains fall in a short period, rivers and streams fill up quickly. Urban drainage systems cannot cope with such a volume of water simultaneously, leading to rapid road flooding and flash floods, as happened in South Gujarat. The Meteorological Department indicates that rain exceeding 204.5 mm in 24 hours is classified as 'extremely heavy rain', but in many areas of Gujarat, the amount of rainfall exceeded this figure two, three, and even four times. The highest amount—906 mm—was recorded in Umbargaon, which is significantly above normal.
IMD forecasts the possibility of heavy and very heavy rains in several districts of Gujarat in the coming days, although the peak intensity of precipitation may gradually decrease. Nevertheless, additional rains could worsen the problems in areas where water has already accumulated. Residents are advised to avoid flooded roads, stay away from rivers and streams, and follow the advice of the Meteorological Department and local authorities. The monsoon demonstrated how serious a problem rain falling in just a few hours can become, causing floods in South Gujarat. The Meteorological Department emphasizes the need for vigilance in the coming days, as even a small amount of precipitation can worsen the situation in already waterlogged areas.
