Frequent western disturbances causing extreme weather in hilly states: Scientists

India Today

30-04-2025

Back-to-back western disturbances have led to heavy rainfall in Himalayan states, making them vulnerable to extreme weather events, meteorologists have said.Last week, flash floods and landslides occurred in several parts of Jammu and Kashmir, while parts of Himachal Pradesh and Uttarakhand recorded heavy rainfall earlier this month, triggering floods and landslides.However, the back-to-back western disturbances have been able to keep a check on the prolonged heatwaves in the northwestern plains so far, said Mahesh Palawat, Vice President of Meteorology and Climate Change at Skymet Weather, a private weather forecasting entity.advertisement
"Heatwave has made on and off appearance over the northwestern plains as an increased frequency of western disturbances has been affecting the flow of dry and hot northwesterly winds. These warmer winds are replaced with easterly winds, which are comparatively cooler and are bringing temperatures down," he said.Palawat added that parts of central and west India have also not seen prolonged heatwave spells due to the changing wind patterns.Dr KJ Ramesh, former Director General of Meteorology, India Meteorological Department, said a rise in the frequency of western disturbances has made the Himalayan states more vulnerable to extreme weather events, directly linked to climate change."After remaining insignificant till January, western disturbances picked up frequency from late January onwards and have been affecting western Himalayas at regular intervals. The influence of western disturbances has been growing significantly over Jammu and Kashmir, Himachal Pradesh and Uttarakhand. They have been dumping more rainfall over the Himalayan region, which is directly related to climate change," he said.advertisementWestern disturbances are storms that predominantly affect north India and Pakistan during winters. These weather systems are embedded within the subtropical westerly jet that lies over the Indian region. Western disturbances travel across the year, but in different latitudes.They travel in lower latitudes during winters, bringing significant amounts of rain and snow over north India. In summers, these weather systems tend to travel to higher latitudes, confining snow and rainfall activities to the higher reaches of the region.It is known fact that the rising global temperatures are instrumental in amplifying the extreme weather events led by western disturbances."Global warming has led to rapid warming of the Arabian Sea, which then emits more moisture northwards. When the amplitude of western disturbances extends up to the North Arabian Sea, more moisture is fed into the system, resulting in intense weather activity over the hills," Dr Ramesh said."If we see the snow water equivalent anomaly, there is the presence of unusual snowfall. In a large sense, their weather patterns this year show a different trend," he added.Snow water equivalent is the depth of water that would cover the ground if the snow cover was in a liquid state.Scientists have warned against an increasing erratic trend in western disturbances amid global warming."Western disturbances will now have more meridional oscillations, which means that they can now travel to the north boundary as well as to the south boundary of the jet. Earlier, there was not enough space for such oscillations in comparison to the present situation. They are also getting uplifted and are now reaching up to Karakoram range, bringing more snowfall there," said Dr Ramesh.
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