Pune: Drought has crept up on people, especially farmers, like a slow disaster for centuries. The first sign is always the failing rains, followed by shrinking water in dams, which ultimately means reduced water for crops, and soon, a crisis unfolds.But a new study suggests that across Maharashtra, drought is increasingly behaving differently, arriving within weeks.Researchers from Maulana Azad National Institute of Technology (MANIT), Bhopal, studied rainfall, temperature, soil moisture and atmospheric moisture demand between 1981 and 2024 in 36 districts across Maharashtra to understand how flash droughts develop and evolve.Unlike conventional droughts, which build up over months, flash droughts develop rapidly because rainfall deficits coincide with high temperatures and rapidly drying soils.The biggest difference between a conventional drought and a flash drought is how fast they develop. “In a flash drought, very high temperatures, dry air, and rapid loss of soil moisture combine with low rainfall, causing the land to dry out much faster,” Vikas Poonia, lead investigator and head of the hydroclimatology lab at MANIT said.Poonia, along with Deepika Yadav, a PhD scholar at MANIT, published the paper in the Physics and Chemistry of the Earth journal.But not every hot or dry week is a flash drought. It can be identified only when there is a rapid and sustained decline in moisture conditions, along with continuing dry conditions for several weeks.“In our study, we only considered an event to be a flash drought if the drying continued for at least 24 days and met specific scientific criteria based on the aridity Index. So, a few rainless days or a short heatwave is simply weather. Flash drought is a rapidly developing climate event that has real impacts on crops, soil moisture and water availability,” Poonia said.Predicting flash drought is more challenging than normal drought. “Because flash drought develops rapidly, it requires continuous monitoring rather than waiting until rainfall becomes very low. By tracking several factors together, such as rainfall, soil moisture, temperature and atmospheric dryness, we can detect early warning signs before the drought becomes severe,” Poonia said.Their study used the Aridity Index (AI) to identify FD. “It compares the rainfall received divided by the potential evaporation — how much water the atmosphere wants to remove. This is important because drought is not controlled only by rainfall. Even if rainfall is close to normal, unusually high temperatures and dry air can cause water to evaporate much faster, leading to rapid soil drying and flash drought,” said Poonia, apart from precipitation, temperature, soil moisture and vapour pressure deficit which measures atmospheric dryness.The study used scientific datasets covering 1981–2024 from India Meteorological Department, Global Land Evaporation Amsterdam Model, ERA5 reanalysis dataset developed by the European Centre for Medium-Range Weather Forecasts and NCAR/NCEP reanalysis, which was used to calculate vapour pressure deficit.“All datasets were converted to the same spatial and temporal resolution so they could be analysed consistently across Maharashtra,” Poonia said.Where are the hotspotsAccording to the research paper, FDs occurred more frequently in sub-humid and humid regions such as Gadchiroli, Chandrapur, BhandaraWhereas, semi-arid interior districts, particularly Ahilyanagar, Beed, Dharashiv, Sangli, and Solapur, experienced comparatively more severe and rapidly intensifying FD events, highlighting their greater hydro-climatic vulnerabilityThe researchers found that FDs, during their 44-year-study, occurred much more frequently during the non-monsoon season, with many areas experiencing 15–25 events, and some locations recording more than 25 events over the 44-year period.They recommended integrating soil moisture, atmospheric dryness and temperature into drought monitoring systems instead of relying primarily on rainfall, arguing that such an approach could improve early warning systems and strengthen climate-resilient agriculture and water management across Maharashtraquote Gadchiroli and Chandrapur experienced flash droughts more often because changing weather conditions triggered more events. However, districts like Ahilyanagar, Beed, Dharashiv, Sangli and Solapur already have hotter and drier climates. When flash drought starts there, soil moisture disappears much faster, making the drought more intense and more damaging, even if it occurs less frequentlyDeepika Yadav, a PhD scholar at MANIT, Bhopal.
