Uttarakhand flood maps could also be underestimating danger, research warns

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A flood-like scenario in a village in Chamoli, Uttarakhand, following heavy rains is seen on this July 8, 2025, {photograph}.
| Picture Credit score: PTI

Flood hazard assessments for Uttarakhand have routinely underestimated the hazard to its cities and villages as a result of they’ve leaned on long-term common rainfall figures moderately than the intense downpours that truly set off disasters, in response to a research in Present Science. The findings arrive at a second when the Himalayan state is grappling with what local weather scientists describe as a sharpening sample of cloudbursts, glacial lake outbursts, and flash floods.

The research, led by researchers on the Malaviya Nationwide Institute of Expertise, Jaipur, tracked how flood hazard zones have intensified in 2017-2021. Areas categorised as ‘excessive’ or ‘extreme hazard’ zones rose noticeably over that interval, with 2021 displaying the biggest extent of ‘high-hazard’ land. Throughout all of the years examined, greater than 90% of Uttarakhand fell inside reasonable or high-hazard classes.

The researchers mapped flood hazard zones throughout Uttarakhand utilizing a Geographic Data System (GIS), a preferred digital mapping know-how utilized by planners in every single place. They mixed six components to evaluate the place floods are most definitely: elevation, slope, drainage density, topographic wetness, land use, and rainfall. Every issue was assigned a weight reflecting its affect on flooding. Slope, elevation, and rainfall have been judged a very powerful; land use, drainage density and wetness have been handled as secondary.

The map was then drawn as soon as utilizing the best rainfall recorded in a given yr and as soon as utilizing the typical of these annual peaks throughout three a long time. The distinction was stark. When the heaviest yearly rainfall was used, extreme and high-hazard zones expanded throughout the state. When long-term averages have been used as an alternative, these zones appeared to shrink. The authors argued that typical strategies counting on common values could give planners a false sense of security.

The findings carry weight in a state that has witnessed a sequence of catastrophes during the last twenty years, from the Malpa landslide of 1998 and the Kedarnath catastrophe of 2013, through which Uttarakhand acquired 375% of its benchmark monsoon rainfall, to the Chamoli flood of 2021. Local weather scientists have linked the rising frequency of utmost rainfall within the Himalayas to a warming environment. Constructed-up areas, the research famous, have additionally expanded throughout the State, leaving much less land in a position to soak up runoff.

The authors advocate flood maps be redrawn round excessive rainfall situations moderately than long-term averages, and that buffer zones be created round essentially the most susceptible terrain. Discipline validation towards noticed flood knowledge, they added, might be important earlier than such maps information coverage choices.

Revealed – Could 08, 2026 07:45 am IST