Himachal’s Dry Spells Growing Longer, Study Flags Changing Rainfall Pattern

Himachal Pradesh is seeing longer dry spells, pointing to a gradual shift in rainfall patterns across the Western Himalayas, according to a comparative study of Himachal Pradesh, Jammu & Kashmir and Uttarakhand.

The study, which analysed rainfall data from 1981 to 2020, found that consecutive dry days in Himachal have increased at an average rate of 4.1 days per decade. Five-year rolling averages also showed a gradual increase in the duration of dry periods in the state.

Published recently in the international journal Discover Geoscience, the research was carried out by Kritika Nag, Sujata Pattnaik, Velusamy Venkataramanan, Vartika Sharma and M.S. Shekhar. The researchers are associated with IGNOU, the National Centre for Medium Range Weather Forecasting (NCMRWF) and the Defence Geoinformatics Research Establishment (DGRE).

Interestingly, the study found that rainfall trends are not uniform across the Western Himalayas.

While Himachal Pradesh recorded longer stretches of dry weather, Jammu & Kashmir witnessed a significant decline in overall rainfall, rainfall intensity and the frequency of moderate to heavy rain. Uttarakhand, on the other hand, showed no statistically significant long-term changes in the rainfall indicators examined during the study period.

Based on India Meteorological Department data, the study found that total rainfall in Jammu & Kashmir declined by around 95.41 mm per decade. The region also saw decreases in the average intensity of rainy days and in the frequency of days receiving 10 mm, 20 mm or more rainfall.

Researchers said the contrasting trends across the Himalayan states could be influenced by several atmospheric and geographical factors, including elevation, mountain topography, the movement of air over mountainous terrain and Western Disturbances. Together, these factors shape how much rain or snow different areas receive, its intensity and how frequently precipitation occurs.

Meanwhile, Dr Surender Paul, Regional Director of the India Meteorological Department for Himachal Pradesh, Punjab and Haryana, said monsoon rainfall had declined over the past decade. He said he would examine the research paper to better understand its findings.

The findings are particularly significant for Himachal Pradesh, where changing dry spells could have implications for water availability, agriculture and fragile mountain ecosystems. Continued monitoring could help provide a clearer picture of how rainfall and drought risks are evolving across the region.

The study also highlights an important point: climate and rainfall changes across the Western Himalayas are not following a single pattern. While Himachal is experiencing longer dry spells, neighbouring Himalayan regions are showing different trends, underlining the need for region-specific research and climate assessments.