A new study involving LIQUIDICE researcher Ross Woods reveals an increasing risk of rain-on-snow floods in the Tianshan Mountains of Central Asia. The findings point to a potential shift in the timing of major flood events, with important implications for water management in the region.
Rain falling on an existing snowpack can accelerate snowmelt and generate large volumes of water in a short period of time, increasing the risk of flooding downstream. These events, known as rain-on-snow (ROS) events, are an important example of how changes in the atmosphere, snow cover and hydrological processes interact in a warming climate.
A new paper, “Linking Rain-on-Snow Events to River Floods in the Tianshan Mountains”, led by Dr Fan Sun from the Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, investigates how these events have changed over the past seven decades and how frequently they translate into high river flows.
The researchers analysed climate and hydrological data from 40 river basins across the Tianshan Mountains, often referred to as the water tower of Central Asia. Their findings show that conditions favourable for rain-on-snow floods have become more frequent in 30 of the 40 studied rivers over the last 70 years. This increase is primarily associated with rising spring rainfall under warmer temperatures. The study also identifies a substantial increase in high river-flow events attributable to rain-on-snow. Comparing the two halves of the study period, the researchers found approximately 45% more such events in the second half. Importantly, the findings suggest that the seasonal pattern of flood risk may be changing. Traditionally, snowmelt floods have been most significant during summer. However, increasing spring rainfall combined with warmer temperatures could shift part of this risk towards earlier in the year, making rain-on-snow floods an increasingly important concern.
These changes matter not only for flood prevention but also for water management. River flows generated by rain and snowmelt are valuable resources for hydropower production and irrigation. Changes in their timing and frequency may therefore require adjustments to existing water-management practices.
As climate warming continues, understanding the changing relationship between rainfall, snow cover and river flows will be essential for anticipating future hydrological risks and managing water resources in mountain regions. The research contributes to a better understanding of climate-driven changes in cryosphere–hydrology interactions, a key topic addressed by the LIQUIDICE project.
Sun, F., Woods, R., Hao, X., Li, Y., Fang, G., Liang, Q., Ci, M., Zhang, J. & Kulaixi, Z. (2026). Linking Rain-on-Snow Events to River Floods in the Tianshan Mountains. Weather and Climate Extremes, 54, 100968.