The HKH monsoon outlook warns that long dry spells may be interrupted by sudden heavy downpours, raising the risk of both droughts and floods.
Warmer and drier conditions could increase the likelihood of heatwaves, water stress and wildfires across the Hindu Kush Himalaya.
The region is entering the monsoon with lower-than-normal snow cover, reducing its seasonal water buffer.
Short, intense rainfall bursts could trigger flash floods, landslides and glacial lake outburst floods in vulnerable mountain areas.
Experts say impact-based forecasting and stronger preparedness are urgently needed in the climate-vulnerable HKH region.
Monsoon 2026 across much of the Hindu Kush Himalaya region could be hotter and drier than normal, while still carrying the risk of short, extreme rainfall events, according to a new outlook by the International Centre for Integrated Mountain Development.
The HKH Monsoon Outlook 2026, issued by ICIMOD on June 11, 2026, said many parts of the region, including Bhutan, Nepal, India and Pakistan, may experience below-normal rainfall and above-normal temperatures during the season. Developing El Niño conditions in the equatorial Pacific Ocean could influence rainfall and temperatures during the season, the report said.
The outlook warned that long dry spells could be interrupted by sudden heavy downpours, raising the risk of droughts as well as floods. Glacial lake outburst floods (GLOF) occur when water stored in glacial lakes is suddenly released, often with destructive force.
The Hindu Kush Himalaya (HKH), spanning eight countries, contains the largest concentration of snow and ice outside the polar regions. It is also the source of several of Asia’s major river systems, including the Amu Darya, Indus, Ganga, Brahmaputra, Yangtze and Mekong, which sustain billions of people downstream.
ICIMOD’s outlook brings together forecasts from several regional and global systems, including its own HKH Sub-seasonal to Seasonal prediction system, supported by the Institute of Atmospheric Physics at the Chinese Academy of Sciences.
It also draws on forecasts from the Asia-Pacific Economic Cooperation Climate Centre, the Copernicus Climate Change Service of the European Centre for Medium-Range Weather Forecasts, the International Research Institute for Climate and Society, and the 34th session of the South Asian Climate Outlook Forum.
The HKH Sub-seasonal to Seasonal system predicted below-normal precipitation across most of the region. Exceptions are expected in parts of the north-west and east, including Afghanistan, Myanmar and Bangladesh, where rainfall could be normal to above normal. Other forecasting systems broadly point in a similar direction.
The report warned that during the monsoon season, long dry spells could be interspersed with abrupt heavy downpours, raising the risk of both droughts and floods. “These projected warmer and drier conditions may increase the likelihood of droughts, heatwaves, water stress, and wildfires across the HKH. However, localised episodes of intense rainfall may also occur, which could trigger flash floods, landslides, and GLOFs in vulnerable mountain areas,” the report said.
The HKH S2S expected above-normal daytime and night-time temperatures for most of South Asia, with cooler-than-normal temperatures along the western, northern and eastern margins of the territory. Other forecasting systems have made similar temperature predictions.
Drier-than-normal conditions, combined with increased temperatures, could lead to heat and water stress for people in the region. Temperatures could be 0.5 degrees Celsius (°C) to 2°C higher than the 2010-2024 normal.
Snow cover at the beginning of the monsoon season is also lower than normal, which could further reduce water availability.
“Lower snow persistence means the region is entering the monsoon with a reduced seasonal water buffer,” said Sarthak Shrestha, remote sensing and geo-information associate at ICIMOD and co-author of the report.
“Localised climatic conditions, influenced by topography and land-cover characteristics, may bring shorter but more intense bursts of rainfall,” the report said. This could lead to flash floods and landslides in the region. Such bursts of rainfall could also be aided by the unusual occurrence of western disturbances during the monsoon season.
“Western Disturbances (WD) are extratropical weather systems that primarily affect the HKH during winter and pre-monsoon months, from November to April. During the core monsoon season, from June to September, the prevailing atmospheric circulation shifts northwards, and the jet stream moves northward, which typically suppresses WD activity over the HKH,” Arun Bhakta Shrestha, senior adviser at ICIMOD and chief executive of Hydrominds Asia, told Down To Earth.
“But scientific reports suggest a delay in the northward retreat of the subtropical jet stream is delaying monsoon onset. Western disturbances have been more active on the edges of the monsoon season, in June and September,” he added.
Even if the overall monsoon is drier than normal, western disturbance intrusions can trigger intense, localised cloudbursts that cause flash floods and landslides with little warning, Shrestha said. “A dry season on average can mask a very dangerous extreme event,” he stated.
Rising temperatures are also expected to accelerate glacier melt and snowmelt, heightening the risk of GLOFs, and contributing to short-term increases in river discharge, according to the report.
“Sectoral implications may include reduced agricultural productivity due to heat and moisture stress, increased pressure on water supply systems, higher electricity and energy demand, elevated public health risks from extreme heat, and the need to strengthen drought preparedness alongside continued readiness for flash floods and landslide events,” the report said.
“With the frequency and intensity of these events rising in the region, there is an urgent need for greater preparedness against hydro-meteorological hazards, including planning for adaptive, risk reduction measures,” the report added.
The report said it was therefore important to conduct impact-based forecasting of key weather parameters in a disaster-prone climate change hotspot such as the HKH, alongside forecasts made at the beginning of the season.