Western Disturbances

A common query that may arise while learning about India’s climatic conditions, is that how come the northern regions of India experience a pattern of rainfall that is not the same as that in the central or the southern part of the country? This difference in rainfall pattern in the subcontinent is mainly because of the extratropical storms in the area called western disturbances. These winds bring sudden rainfall in the country during the non-monsoon seasons. 

The climatic change in India constitutes an important part of the IAS syllabus. Thus, candidates preparing for the upcoming exam must go through the details mentioned further below in this article.  

To read in detail about Climate Change in India, candidates can visit the linked article. 

What Are Western Disturbances?

The UPSC notes on geography define these extratropical storms as a specific precipitation pattern. The precipitation pattern of any storm is guided by the flow of currents in the region. Unlike most tropical storms that carry moisture from the upper regions to the lower regions, this kind of storm flows in the opposite direction, from lower to upper atmosphere. 

The Westerlies guide the precipitation pattern for the western disturbances, and as a result, they are crucial for growing Rabi crops, such as wheat. Therefore, western disturbances in India are quite a significant phenomenon originating in the Mediterranean. 

Western Disturbances Mechanism 

Western disturbances UPSC questions delve deep into the formation and mechanism of this storm since its impacts are huge for the agriculture of India. Since it is a storm, it originates in the ocean, so it picks up so much moisture on its way. The way tropical storms function is that they pick up moisture in the upper atmosphere and provide rainfall to the lower atmosphere, but in this case, the air causing the storms originate in Ukraine. 

The UPSC exam includes questions regarding how this storm travels from Ukraine to Northern India and what compels it to do so. The high-pressure region in Ukraine creates a cold air intrusion from the polar regions with high moisture. This makes an extratropical depression of eastward movement, and this depression moves to the Indian subcontinent at a relatively fast speed. However, once it reaches the Himalayan-mountain range, it ceases to develop. Thus, this stoppage in development causes the rains in the region. 

Effects of Western Disturbances in India – UPSC  

The UPSC prelims often ask questions regarding the immediate and long-term impacts of this storm for India. As stated earlier, they are vital for the growth of Rabi crops that grow in the winter, such as locally produced wheat. One of the reasons this storm is associated with agriculture is that rainfall dictates the fertility and compatibility of soil for crop growth. In this case, it is a net positive. 

However, the western disturbances are not always a blessing since it also causes a lot of soil erosion. Since the rainfalls are scattered and the density is quite high, it often results in the topmost layer of the earth getting washed away in the regions of Northern India. Similarly, they are also responsible for prolonged cloudy skies and higher night temperatures. Moreover, in the case of very heavy rainfall, significant crop damage is also observed, especially with the formation of thick fog and mist. Lastly, the heavy downpour also results in severe landslides and even avalanches in the region. 

The western disturbances are, therefore, quite significant in how they bring rainfall to the northern regions of India. They are not only responsible for rainfall in the region, but they are also an aspect of a very specific and somewhat destructive environmental phenomenon since they are extratropical storms. 

The impacts of these storms lie in how they alter the land temperatures in the region, how they affect crop growth, soil erosion and so on. Therefore, even though they are a vital part of the environmental system in India, their negative effects impact the country more devastatingly, since it is fundamentally a non-monsoonal precipitation pattern. 

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