Cloudbursts in India
A cloudburst is an extremely intense rainfall event typically 100 mm (≈4 inches) or more in under one hour, localized in a small area.
Why Do Cloudbursts Happen?
Orographic Uplift: Moist air pushed up mountain slopes cools and condenses quickly.
Thunderstorm Dynamics: Strong convection builds up water-heavy cumulonimbus formations.
Atmospheric Instability: Sudden weakening of upward currents allows rapid fall of accumulated moisture.
Topography & Land Use: Steep slopes, deforestation, unstable terrain amplify water run-off speeds.
Climate Change Effects: Increasingly frequent and intense events linked to global warming trends, glacier melt, and changing monsoon patterns.
Impacts of Cloudbursts
Flash floods: torrents of muddy water that sweep through valleys, villages, and road networks. Often accompanied by landslides.
Destruction of infrastructure and property: homes, hotels, markets, bridges, roads and phone/internet lines are wiped out.
Human toll: fatalities, injuries, and people buried or trapped under debris. Many go missing.
Environmental disruption: riverbeds, vegetation, and agricultural lands washed away.
Rescue and relief challenges: difficult terrain, communication breakdown, delayed aerial response.
Predicting cloudburst
Doppler radars can be helpful in predicting the Cloudburst. But not all of the Himalayas, where a cloudburst is most likely, has a Doppler radar.
According to IMD, it is very difficult to predict cloudbursts due to its very small scale in space and time. To monitor or nowcast (forecasting few hours lead time) the cloudburst, we need to have dense radar network over the cloud burst prone areas or one need to have a very high resolution weather forecasting models to resolve the scale of cloud burst.
Cloudburst incidences over many areas of Himalaya often go unnoticed due to the absence of meteorological observatories. Many a times these come to notice only when these are accompanied by losses and casualties. In the absence of losses these can only be identified on the basis of inundation occurring along streams.
Areas Prone to Cloudburst in India
Hilly areas in Himachal Pradesh, Uttarakhand, the northern areas of West Bengal, Sikkim, Arunachal Pradesh, Manipur, Mizoram, Meghalaya, Nagaland and Tripura and the coastal areas in the states of West Bengal, Orissa, Andhra Pradesh, Tamil Nadu, Karnataka, Kerala, Maharashtra and Gujarat and Union Territories (UTs) of Andaman and Nicobar Islands and Lakhshadweep are more prone to such phenomena. Such events have also occurred in the states of Rajasthan, Chattisgarh, Madhya Pradesh and Uttar Pradesh.
Cloudburst History in India
India’s mountainous landscapes have been repeatedly hit by catastrophic cloudbursts:
1908: Flood on Musi River ~15,000 people died, thousands of homes destroyed.
1970: Upper Alaknanda valley in Uttarakhand heavy sediment transport and village destruction.
1997–98: When cloudbursts triggered floods in Himachal Pradesh and Uttarakhand’s Pithoragarh district hundreds perished.
2003–04: Events in Himachal and Chamoli killed scores and stranded thousands of pilgrims.
2010: Leh, Ladakh, series of cloudbursts killed over 1,000 people and injured hundreds.
2013 Uttarakhand floods: Monsoon-triggered cloudburst led to over 6,000 deaths, affected 4,500+ villages, the worst natural disaster in modern India.
2021 Hunzar, Kishtwar: 26 deaths, many missing in remote J&K highlands.
Recent years have seen multiple smaller but damaging events across Uttarakhand, Himachal, Sikkim, and Karnataka.
A 2022‑2023 study identified Uttarakhand as an emerging hotspot for cloudbursts and extreme rainfall especially along its major geological fault zones, driven by regional climatic shifts and landscape changes.
The 5 August 2025 Uttarkashi Event
What Happened
On 5 August 2025, a powerful cloudburst was initially reported to have struck the upper catchment of the Kheer Ganga River near Dharali village, in Uttarkashi district, Uttarakhand. The catastrophic disaster, now referred to as the “Dharali Disaster 05 August 2025,” was the result of a complex interplay of high-risk geomorphological, hydrological, and climatic factors.
The high-altitude Himalayan setting of the region is marked by steep and unstable slopes, overhanging rocks, active glaciers, unconsolidated moraine deposits, and loose slope wash material, making the terrain highly vulnerable to sudden failures. Steep stream gradients, persistent snow cover, underlying permafrost, and glacial depressions containing partially impounded water likely served as natural reservoirs for sudden and forceful water releases. Narrow drainage channels and paleo-alluvial fan deposits near the outlet zone may have further amplified the disaster by accelerating and concentrating the flow of water and debris.
Prolonged 3–5 days of intense rainfall had already saturated the unconsolidated morainic deposits, reducing their cohesion and increasing pore water pressure ideal conditions for massive debris flows, mudslides, and flash floods. The immediate trigger was first believed to be intense rainfall combined with a sudden cloudburst. However, later statements by the India Meteorological Department (IMD) and the Wadia Institute of Himalayan Geology indicated that it may not have been a classical cloudburst. Instead, the possibilities include a glacial lake outburst or a heavy rainfall-triggered landslide of accumulated silt and debris, both of which could have initiated cascading hazards including flash floods, debris flows, and landslides.
[Glacial lake outburst (technically called a Glacial Lake Outburst Flood or GLOF) is a sudden release of water stored in a lake that forms at or near a glacier.
-
How it forms:In the Himalayas, melting glaciers often leave depressions that fill with meltwater, forming glacial lakes. These lakes are usually dammed by loose material such as moraine (unconsolidated rock and debris left behind by the glacier) or by ice itself.
-
Why it’s dangerous:The moraine or ice dam can be unstable. Heavy rainfall, melting due to high temperatures, or seismic activity can weaken it.If the dam fails suddenly, a massive volume of water rushes downstream with huge destructive power sweeping away rocks, debris, and sometimes entire settlements.]
Human & Material Loss
The deluge swept into the valley, destroying homes, shops, hotels, roads, and a local market.
Confirmed deaths: At least 5 (as of August 8, 2025)
-
Missing: Over 50 people, including 8 army personnel, more than a dozen Nepali nationals, and 16 tourists from Maharashtra’s Jalgaon district.
-
Rescued: By August 8, Army, ITBP, NDRF, SDRF, and BRO had rescued 150-175 people.
-
Tourists: Maharashtra govt confirmed contact with 120 of 151 stranded tourists; 31 remain unreachable.
-
Evacuations:
-
307 pilgrims from Gangotri to Mukhwa (ITBP)
-
190 people from Dharali (August 6)
-
Multiple airlifts from Harsil, Nelong, and Matli
Nearly 20-25 hotels and homestays along the Gangotri pilgrimage route were washed away, along with multiple shops and other buildings.
A key bridge was destroyed, and debris blocked the Badrinath National Highway near Pipalkoti.
Rescue Operations
Teams from the Indian Army, NDRF, SDRF, ITBP, and local administration launched rescue and relief efforts. However, operations were severely hampered by washed-away helipads, broken roads, unstable slopes, and communication blackouts. Multiple helicopters were requested, but heavy rainfall and unstable terrain delayed aerial assistance. Authorities issued a red weather alert across Uttarakhand, warning of further intense rainfall between 6-9 August.
- Forces involved: Army, ITBP, NDRF, SDRF, BRO, medical teams.
- Equipment: Helicopters (including IAF Chinook), drones, cadaver dogs (first-ever NDRF deployment), ground-penetrating radar, satellite communication.
- Medical Aid:
- 9-member team to Harshil & Dharali by helicopter.
- 12-member specialist team at Matli.
- 70 injured treated; many airlifted.
- Challenges: Washed-out helipads, multiple major slide points, destroyed bridge, unstable slopes, bad weather.
- Satellite Support: ISRO’s Cartosat-2S provided very high-resolution imagery for rapid damage assessment.
Political & Relief Measures
-
Chief Minister Pushkar Singh Dhami:
-
Donated a month’s salary to relief funds.
-
Announced ₹2 lakh ex-gratia to families of landslide victims and ₹1.3 lakh to building owners with destroyed houses.
-
Personally visited disaster sites and hospitals.
-
-
Public Appeal: Urged officials, NGOs, and citizens to assist “according to their capacity.”
Broader Context & Lessons
This disaster reflects the growing threat of cloudburst-induced hazards in the fragile Himalayan system. Historically, traditional ecological wisdom guided communities to establish villages at safer distances from riverbanks, nallahs, and flood-prone zones. Today, such wisdom is often overlooked in the rush for development, leading to increased settlement in highly sensitive areas like river valleys, alluvial fans, and depositional plains.
Scientific understanding of the Himalayan mountain system remains limited, and yet, unregulated human encroachment continues unabated without adequate hazard assessment or environmental safeguards. The Dharali event serves as a stark warning of the consequences of unchecked development, climate change driven extreme rainfall, and inadequate planning.
Help Uttarakhand Flood Victims
Floods worsened by climate change have left many in Uttarakhand homeless and in urgent need of aid. You can support relief efforts through trusted organizations like Donatekart, IAHV–USA, Plan India, or through the State or Central Government’s official disaster relief funds.
How to donate:
-
Visit official websites or Instagram pages for direct links
-
Contribute via online payment, bank transfer, or relief kit sponsorship
Your kindness can provide shelter, food, medical aid, and long-term support. Please give what you can.
Comments
Post a Comment