Which Uttarakhand districts are most vulnerable to impacts of cloudbursts and why?
A flash flood in Uttarkashi has claimed five lives and left many missing. The incident highlights the increasing vulnerability of the Himalayan region to extreme rainfall and cloudbursts exacerbated by climate change and geological factors. Experts point to rising temperatures, increased glacial lake expansion, and human activities like deforestation as contributing factors to the rising frequency and intensity of such disasters.
New Delhi: At least five people have lost their lives and several others are reported missing in Dharali village of Uttarkashi district in Uttarakhand due to flash floods triggered by cloudburst. A number of multi-storey buildings have collapsed and tonnes of debris have gathered.
Uttarkashi lies in the central Himalayan region. This area has witnessed a number of extreme rainfall events. According to studies by the Uttarakhand State Disaster Management Authority (USDMA), Uttarkashi, Chamoli, Rudraprayag, Bageshwar, and Pithoragarh have been identified as extremely vulnerable to the impacts of cloudbursts and intense rainfall, the Hindustan Times reported. Since temperatures in the Himalayan zones have seen a spike in recent years, the severity and frequency of the rainfall is also growing, the USDMA findings show. What's more, these districts also fall within the high-risk Main Central Thrust (MCT) seismic zone, which has seen a spate of earthquakes in recent years.
Since January this year, as many as 17 earthquakes have occurred in Uttarakhand, as per the National Centre for Seismology. Out of these, 14 occurred in the Main Central Thrust (MCT) zone, covering the districts of Uttarkashi, Rudraprayag, Bageshwar, and Chamoli.
According to some experts, the Garhwal-Kumaon Himalaya is highly vulnerable to cloudbursts and extreme rainfall because when monsoon clouds hit the main Himalayan range, they are forced to rise, which leads to the formation of dense Cumulonimbus clouds, which are towering storm clouds with a flat base at low altitudes.
In 2022, a study by the Department of Science and Technology said expansion of glacial lakes and its bursting during monsoon due to extreme rainfall events cause higher damage. A glacier collapse or glacial lake breach upstream — and not cloudburst — could be behind the flash flood that swept away Dharali village in Uttarkashi district on Tuesday, experts analysing meteorological and satellite data said, reported Times of India.
'Steep slopes go a long way in contributing to flash floods'
The HT report pointed out that there are 118 high altitudinal lakes located in Chamoli, Pithoragarh, Rudraprayag and Uttarkashi districts. A maximum 60 are in Chamoli districts and 32 in Uttarkashi. The Department of Science and Technology study said: "These lakes are fed by glacier melt water as maximum are located in snout areas and also receive enough precipitation during monsoon.”
A new study by researchers based at the Indian Institute of Technology (IIT)- Gandhinagar, which was published in the journal Nature Hazards on July 13, pointed out that only 25% of flash floods in India are directly caused by extreme precipitation, the remaining cases are caused due to a combination of extreme rain and the soil’s condition before the precipitation. The study also said that it in the Himalayas, steep slopes go a long way in contributing to flash floods. Road-widening, construction activities, and deforestation lead to the creation of steep vertical slopes, which worsen the impact of natural disasters.
The study added that with temperatures rising around the world, extreme weather events like flash floods are becoming deadlier and more frequent. This is because for every 1°C increase in average temperature, the atmosphere can hold roughly 7% more moisture — resulting in heavier rainfall and a higher risk of flash flooding.
The region’s geology is fragile, and adding to its woes are the rising temperatures, and human activities that throw rules to the wind. As a result, Uttarakhand is bearing the brunt of flash floods and other natural disasters.