Climate, multi-hazard disaster risk and vulnerability profile of Bhutan
1. Overall risk profile
Bhutan is a high-mountain, landlocked Himalayan country where climate and disaster risk is shaped by steep topography, fragile geology, intense monsoon rainfall, rapid elevation changes, glacier retreat, expanding glacial lakes, river-valley settlements, and high dependence on climate-sensitive sectors. Its dominant hazards are river floods, flash floods, urban floods, landslides, glacial lake outburst floods, earthquakes, extreme heat, forest fires, windstorms, hailstorms, drought/dry spells, drying water sources, pest and disease outbreaks, and climate-sensitive health risks. ThinkHazard classifies Bhutan’s river flood, urban flood, landslide, extreme heat and wildfire hazards as high, while earthquake and water scarcity are medium and cyclone is low. (Think Hazard)
Bhutan’s climate risk is not only a hazard problem; it is a development, infrastructure, hydropower, food-security, water-security and mountain-governance problem. The World Bank’s 2025 Bhutan climate and development analysis notes that about 65% of the population is exposed to at least one natural hazard, with poverty and hazard risk often overlapping, and that cities are expected by 2050 to face more intense rainfall, higher temperatures and longer dry periods. (World Bank).
2. Climate and geographic setting
Bhutan’s climate varies sharply by elevation. The country is commonly divided into three broad climate zones: the southern foothills, with subtropical conditions, high humidity and heavy rainfall at about 100–1,500 m; the inner Himalayas, with cool winters, hot summers and moderate rainfall at 1,500–3,000 m; and the higher Himalayas, with alpine conditions at 3,000–7,550 m.
More than 70% of Bhutan’s annual rainfall occurs during the southwest monsoon from June to September, making the country highly dependent on monsoon timing, intensity and spatial distribution. This creates a dual risk: excess rainfall causes floods, landslides and erosion, while winter drying and rainfall variability contribute to water scarcity, spring-source drying and agricultural stress.
Observed and projected warming is a central risk driver. NCHM’s climate projection information indicates that under RCP 4.5, Bhutan’s annual mean temperature is projected to rise by 0.8°C–1.6°C during 2021–2050 and 1.6°C–2.8°C by 2070–2099; under RCP 8.5, end-century warming may exceed 2.8°C, with seasonal changes reaching 3.2°C–5.6°C. NCHM also projects annual rainfall increases of 10%–30% under RCP 4.5, and more than 30% over much of Bhutan by late century under RCP 8.5, although rainfall variability remains high. (nchm.gov.bt)
Recent CMIP6-based analysis summarized in Bhutan’s 2026 loss-and-damage assessment projects mean annual warming of 1.6°C–2.7°C by mid-century depending on the SSP pathway, and up to 5.2°C by 2070–2099 under SSP3-7.0. The same assessment notes that summer monsoon rainfall is projected to intensify, heavy precipitation events are expected to increase, and winter months are likely to become drier.
3. Multi-hazard profile
| Hazard | Risk dynamics | Main vulnerable areas and impacts |
|---|---|---|
| River flooding and flash flooding | River and urban flood hazards are rated high nationally. Flood risk is driven by monsoon rainfall, steep catchments, narrow valleys, GLOF potential, sediment load, riverbank erosion and infrastructure located along drainage corridors. (Think Hazard) | Punakha-Wangdue, Chamkhar, Amochhu, Wangchhu, Mangdechhu, Kurichhu, Drangmechhu and southern foothill river systems; impacts include damage to settlements, bridges, roads, hydropower assets, irrigation systems, farms and public services. |
| Urban / pluvial flooding | Urban flood hazard is high, especially where intense rainfall exceeds drainage capacity. Bhutan’s NAP calls for improved stormwater management, sub-basin forecasting and timely dissemination of early warning information to sectors and communities. (Think Hazard) | Thimphu, Phuentshogling, Paro, Gelephu, Samtse, Sarpang and other growing towns; impacts include drainage overflow, road blockage, urban erosion, damage to houses and WASH contamination. |
| Landslides and debris flows | Landslide hazard is high. Bhutan’s NAP states that rainfall events capable of triggering landslides are highly likely to increase, especially in the longer term, and that serious landslide impacts already occur. (Think Hazard) | Mountain roads, national highways, cut slopes, river valleys, hydropower corridors, settlements below unstable slopes and road sections in monsoon-affected districts. |
| Glacial lake outburst floods | GLOF risk is one of Bhutan’s most serious high-mountain hazards. Bhutan’s loss-and-damage assessment reports 2,674 glacial lakes, with 17 considered potentially dangerous, and notes more than 18 recorded GLOF events since the 1950s. | Lunana, Pho Chhu, Mo Chhu, Punatsangchhu, Chamkhar and other glacier-fed basins; risks include sudden destructive floods, debris flows, hydropower disruption, bridge failure, settlement damage and loss of life. |
| Earthquake | Earthquake hazard is rated medium by ThinkHazard, but it remains strategically important because Bhutan lies in the seismically active Himalayan belt and earthquake impacts can cascade into landslides, road failures and damage to buildings. (Think Hazard) | Nationally relevant, especially dense urban areas, schools, monasteries, hospitals, bridges, roads, hydropower infrastructure and heritage structures. |
| Forest fire / wildfire | Wildfire hazard is high. The NAP indicates that forest fire risks are projected to intensify, with broadleaved forests below 2,000 m and chir pine/blue pine zones facing important exposure. (Think Hazard) | Mid-altitude forests, dry valleys, settlements near forest edges, power transmission corridors, protected areas and community forests. |
| Extreme heat | Extreme heat is rated high nationally. Warming is projected to be stronger at high elevations and may increase heat stress in valleys and urban areas. (Think Hazard) | Urban workers, elderly people, children, farmers, construction workers, schools, health facilities and low-altitude southern districts. |
| Drought, dry spells and water-source drying | Water scarcity is rated medium, but dry spells and drying water sources are increasingly important. Bhutan’s NAP notes that dry spells may increase in duration and frequency in large parts of the country, while the 2026 loss-and-damage assessment reports that 69 water sources have dried up and 1,856 sources are in the process of drying. (Think Hazard) | Southern and eastern dzongkhags, rainfed agriculture areas, spring-dependent communities, irrigation schemes, livestock systems and urban water-supply systems. |
| Windstorms, hailstorms and thunderstorms | Agriculture already faces high rainfall variability, thunderstorms, hailstorms and windstorms, with extreme events disrupting agricultural land and supply chains. | Crops, fruit orchards, farm roofs, schools, rural roads, power lines and isolated mountain settlements. |
| Climate-sensitive disease risks | Floods, GLOFs, rainfall, humidity and temperature affect vector-borne and water-borne disease risks. Bhutan’s NAP identifies Chhukha, Punakha and Sarpang as high-hazard districts for vector- and water-borne diseases, and projects future dengue and malaria risk increases under warming scenarios. | Southern and warmer districts, growing urban areas, flood-prone settlements, WASH-vulnerable communities and areas with changing mosquito suitability. |
4. Glacial lake outburst flood risk
GLOF risk is a defining feature of Bhutan’s climate-risk profile because warming temperatures accelerate glacier melt, expand glacial lakes and increase the probability of sudden high-energy flood releases. Bhutan’s 2026 loss-and-damage assessment reports over 700 glaciers, 2,674 glacial lakes, and 17 potentially dangerous lakes, with glacier retreat and lake-terminating glacier expansion increasing exposure downstream.
A 2026 scientific assessment in Natural Hazards and Earth System Sciences selected all Bhutan glacial lakes larger than 0.05 km², totaling 278 lakes, and used hydrodynamic modeling with downstream exposure and vulnerability data to generate GLOF inundation and risk information. The study notes that Bhutan’s landscape ranges from about 200 m in the south to over 7,000 m in the north, and that as of 2020 Bhutan had 2,574 glacial lakes covering about 156.63 km², an increase of 17.7% in number and 20.3% in area from the 1960s. (NHESS)
The most critical GLOF vulnerability is along narrow river valleys where settlements, roads, bridges, hydropower assets, monasteries, farmland and public infrastructure are concentrated on valley floors or alluvial terraces. The GLOF hazard is therefore not only a cryosphere problem; it is a downstream exposure and land-use planning problem requiring lake monitoring, hydrodynamic flood modeling, evacuation routing, siren-based warnings, community drills and risk-informed infrastructure design.
5. Sectoral vulnerabilities
Water resources and hydropower
Water is central to Bhutan’s climate risk. The NAP identifies increased disaster risk, limited water access and seasonal water shortages as key water-sector risks, while hydropower is vulnerable because of high dependence on river flows and exposure to extreme events.
Climate change is expected to produce more erratic rainfall and river-flow regimes. Bhutan’s NAP states that flood, landslide and GLOF risks are likely to increase, and that the hydropower sector will need to adapt existing and new facilities to more variable river flows and higher disaster risk.
Agriculture, livestock and food security
Agriculture and livestock remain highly exposed because Bhutan’s farming systems are shaped by limited arable land, shallow mountain soils, difficult terrain, rainfall variability, pests, diseases, thunderstorms, hailstorms, windstorms, flash floods and landslides. The NAP notes that about half of Bhutan’s population is engaged in agriculture and livestock rearing, while agriculture and livestock contribute about 17% of GDP.
Key agricultural vulnerability pathways include irrigation water shortages, erosion, crop damage from extreme rainfall, road disruption affecting market access, pest and disease shifts, loss of soil fertility, wildlife-crop conflict, labor shortages and climate stress on rangelands and fodder resources.
Forests, biodiversity and ecosystem services
Bhutan’s forests provide water regulation, slope stabilization, carbon sequestration, biodiversity habitat and livelihood resources, but climate change may shift forest structure and distribution, increase pests and diseases, spread invasive species and intensify forest fire risk. The NAP warns that forest fire may undermine carbon-sink functions and that fire behavior is projected to worsen across many forest types.
Forest fire risk also interacts with infrastructure because power lines, roads, settlements and community forests can become ignition or exposure zones. The NAP recommends daily fire forecasting, warning-system integration, fuel management, forest-edge protection and strengthened response capacity.
Health
Climate change affects health through heat stress, vector-borne diseases, water-borne diseases, flood-related contamination, disaster injuries, air quality from fires, nutrition impacts and stress on emergency health services. Bhutan’s NAP identifies changes in vector-borne, airborne and water-borne disease patterns as core health-sector risks.
The NAP’s health-risk assessment finds that Samtse, Chhukha, Punakha and Tsirang rank highest for vector-borne disease risk, while Punakha, Paro, Samtse and Chhukha rank high for water-borne disease risk. It also projects that under business-as-usual warming, dengue cases could increase substantially, with high concentration in Chhukha, Samtse and Thimphu.
Infrastructure, roads and urban systems
Bhutan’s rugged terrain makes road infrastructure highly exposed to rainfall-triggered landslides, debris flows, slope failures, river erosion, bridge washouts and GLOF impacts. GFDRR notes that heavy rains in October 2025 triggered floods, landslides and windstorms across all 20 dzongkhags, damaging transport infrastructure, agricultural land, power supply and telecommunications. (gfdrr.org)
Urban vulnerability is rising as population and assets concentrate in Thimphu, Phuentshogling, Paro, Gelephu and other towns. The World Bank highlights that urban areas face increasing vulnerability to floods and landslides, while resilient infrastructure, climate-informed urban planning, zoning, digital infrastructure and watershed restoration are needed to protect growing urban populations. (World Bank)
6. Geographic hotspots
Bhutan’s NAP climate vulnerability mapping identifies Samtse, Monggar, Sarpang, Punakha and Dagana as among the five most at-risk dzongkhags under present climate-risk conditions. By 2050 under RCP 4.5, Tsirang, Paro, Samtse, Thimphu and Pema Gatshel are projected to show very high risk, with 469,595 people exposed to very high climate-change risk.
The World Bank’s 2025 analysis also notes uneven spatial exposure, with Zhemgang and Mongar in central and eastern Bhutan facing higher risks, while poverty and natural-hazard exposure often overlap. (World Bank)
Important hazard-specific hotspots include:
Punakha-Wangdue and Pho Chhu/Mo Chhu basin: high GLOF, river flood and valley-exposure risk.
Chamkhar, Mangdechhu, Kurichhu and Drangmechhu basins: flood, landslide, hydropower and road-corridor risk.
Southern foothills, including Sarpang, Samtse, Chhukha and Samdrup Jongkhar: heavy rainfall, river flooding, landslides, heat, malaria/dengue suitability, water-borne disease and agricultural vulnerability.
Thimphu-Paro urban corridor: urban flood, slope instability, earthquake exposure, heat increase, infrastructure concentration and high future exposure.
High Himalayas and Lunana region: glacier retreat, GLOFs, alpine rangeland stress, yak-herding vulnerability and difficult emergency access.
7. Institutional and early-warning context
Bhutan has made important progress in disaster and climate-risk governance, including the National Adaptation Plan, hydrometeorological services, GLOF early warning, flood early warning and risk-information systems. The NAP’s final priority sectors include water; agriculture and livestock; forests and biodiversity; human settlements and climate-smart cities; health; energy; and climate services and disaster risk reduction.
The National Center for Hydrology and Meteorology maintains reports and services related to weather, climate, GLOF early warning, hydrological monitoring, flood early warning and climate projections, including SOPs for the Amochhu flood early warning system and GLOF EWS for the Puna-Wangdue Valley. (nchm.gov.bt)
GFDRR and the World Bank are supporting Bhutan’s risk-informed decision-making through a Bhutan DRM Portal, flood-risk data integration, forthcoming earthquake and landslide-risk layers, earthquake loss estimation across 20 dzongkhags, landslide risk assessment of national highways, and agrometeorological decision-support services using machine learning. (gfdrr.org)
8. Priority adaptation and disaster-risk-reduction actions
Strengthen national multi-hazard risk information systems by integrating flood, landslide, GLOF, earthquake, wildfire, windstorm, heat and drought layers into a unified DRM decision-support platform linked with local-government planning.
Upgrade impact-based forecasting and early warning for flash floods, river floods, GLOFs, landslides, windstorms, forest fires, heat stress and climate-sensitive disease outbreaks.
Expand GLOF risk monitoring and mitigation through satellite lake monitoring, lake-level sensors, hydrodynamic inundation modeling, automatic warning stations, controlled lake drainage where feasible, sirens, evacuation routes and regular community drills.
Climate-proof hydropower and river-basin infrastructure through updated design flood standards, sediment-management planning, dam safety, catchment restoration, real-time hydrological monitoring and emergency action plans.
Strengthen landslide and road-corridor resilience through slope-stability mapping, debris-flow inventories, road asset management, bioengineering, drainage improvement, retaining structures, rainfall-trigger thresholds and landslide early warning along critical highways.
Improve urban flood and stormwater management in Thimphu, Phuentshogling, Paro, Gelephu and other towns through drainage master plans, flood zoning, green infrastructure, retention basins, no-build zones, permeable surfaces and solid-waste control.
Scale climate-smart agriculture and livestock systems through resilient irrigation, water harvesting, climate advisories, pest surveillance, crop diversification, rangeland management, fodder security, agroforestry and insurance or contingency support for farm losses.
Protect watersheds, springs and ecosystem buffers through wetland restoration, reforestation, spring-shed management, soil-water conservation, community watershed protection and erosion-control measures.
Strengthen climate-health surveillance for dengue, malaria, diarrheal disease, heat stress and flood-related health impacts, with stronger WASH preparedness in high-risk dzongkhags.
Institutionalize disaster-risk finance and anticipatory action through contingency funds, Cat DDO-type financing, local disaster funds, forecast-based early action protocols, public asset insurance and rapid recovery mechanisms.
Bhutan’s strategic priority should be to move from hazard-by-hazard response toward an integrated mountain multi-hazard risk-management system that connects hydrometeorology, cryosphere monitoring, geospatial CRVA, resilient infrastructure, local adaptation planning, climate-smart agriculture, health surveillance, disaster-risk finance and community-based early warning.