Climate change drives increasing and spatially variable global rain-on-snow events

As global warming continues to intensify, global rainfall frequency is gradually increasing. When warmer rainfall falls on colder snow, destructive snowmelt floods can occur. However, global-scale rain-on-snow (ROS) events research has not yet been carried out, there is still a lack of understanding of ROS events and characteristics to these events at a global scale. Here, global ROS events from 1950 to 2023 are evaluated using the validated 3-hour, 5-km resolution ERA5-Land dataset. We found that global ROS events occur mainly in the middle and high latitudes of the Northern Hemisphere and are increasing in frequency and intensity. Changes in ROS events are linked to climate change, with global warming increasing ROS occurrence. In addition, ROS events are related to the El Niño-Southern Oscillation (ENSO), which promotes the occurrence of interannual ROS events at different elevation ranges. In the future, the mid-high latitude regions of the Northern Hemisphere will still be the areas with the highest conditional probability of ROS events occurring. These results can help to understand and predict changes in the frequency and intensity of global snowmelt floods in the context of ongoing climate change.