From UPSC perspective, the following things are important :
Prelims level : Western Disturbances
Mains level : Western Disturbances and its impact on India
- Under the continued influence of a western disturbance, various parts of the country received unprecedented rainfall and hailstorms few days back.
- A Western Disturbance is an extratropical storm originating in the Mediterranean region that brings sudden winter rain to the northwestern parts of the Indian subcontinent.
- It is a non-monsoonal precipitation pattern driven by the westerlies.
- The moisture in these storms usually originates over the Mediterranean Sea and the Atlantic Ocean.
- Extratropical storms are a global phenomena with moisture usually carried in the upper atmosphere, unlike their tropical counterparts where the moisture is carried in the lower atmosphere.
- They are important for the development of the Rabi crop, which includes the locally important staple wheat.
Importance of Western Disturbances
- The western disturbances affect weather conditions during the winter season up to Patna (Bihar) and give occasional rainfall which is highly beneficial for the standing rabi crops.
- The arrival of these causes precipitation leading to an abrupt decrease in air temperature over North-West India.
- Western Disturbances also bring heavy snowfall in the Himalayan Region and a cold wave to north Indian plains.