A devastating cloudburst struck Dehradun late on 15 September 2025, unleashing very heavy rainfall that led to flash floods, landslides, and widespread destruction across the city and surrounding areas such as Sahastradhara, Tapovan, and IT Park. The sudden deluge buried houses, shops, and commercial buildings under debris, while the overflowing Karligad rivulet caused a bridge collapse on the Dehradun-Haridwar highway, severely disrupting traffic and access. This latest disaster highlights the recurring menace of cloudbursts in India's Himalayan states, where steep terrain, monsoon dynamics, and climate change create the perfect recipe for catastrophe. Understanding how cloudbursts occur, where they strike most often, and the hidden factor behind their increasing frequency is critical for both awareness and disaster preparedness.What is a cloudburstA cloudburst is an extreme weather event where an unusually large volume of rain falls over a very short period in a highly localised area, often exceeding 100 millimetres in just one hour. It is sometimes described as a "rain bomb" because of its suddenness and intensity. Cloudbursts are typically triggered by strong upward currents of moist air that get trapped by mountainous terrain, preventing clouds from dispersing. Once the cloud can no longer hold the accumulating moisture, it releases it all at once, overwhelming rivers, rivulets, and drainage systems.How a cloudburst happensThe process begins when warm, moisture-laden air rises and collides with cooler air at higher altitudes. As the moist air cools, condensation forms dense rain-bearing clouds. In mountainous regions, these clouds often become trapped by the terrain, preventing the moisture from dispersing gradually. Instead, strong upward air currents keep water droplets suspended within the cloud. When the cloud reaches its saturation point, it suddenly releases the accumulated water in a violent downpour. This concentrated release, unlike normal rainfall, produces torrents that overwhelm the land below, often leading to flash floods and landslides.Regions most prone to cloudburstsCloudbursts are particularly common in India's Himalayan belt, including states like Uttarakhand, Himachal Pradesh, Jammu & Kashmir, and parts of the North-East. These regions combine three crucial elements that fuel cloudbursts: moisture from the monsoon, steep mountainous terrain that forces air upward, and unstable weather systems. Uttarakhand, in particular, has witnessed several deadly cloudbursts, including the catastrophic 2013 event that killed thousands and devastated Kedarnath. Towns located near rivers, valleys, or steep slopes remain especially vulnerable.The hidden factor fueling this catastropheExperts warn that climate change is amplifying the risk and severity of cloudbursts. Rising global temperatures allow the atmosphere to hold more moisture, increasing the chances of sudden, intense downpours. At the same time, rapid urbanisation, deforestation, and construction in fragile mountain zones reduce natural drainage and water absorption, magnifying the impact of floods and landslides. This deadly combination means that what were once rare events are becoming more frequent and more destructive. As seen in Dehradun, the toll is not just environmental but also human, with homes, livelihoods, and infrastructure swept away in minutes.

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