Large rock-ice avalanches have attracted the attention from scientists for decades and some of these events have caused high numbers of fatalities. A relation of rock slope instabilities in cold high mountain areas to climate change is currently becoming more evident and questions about possible consequences and hazard scenarios in densely populated high mountain regions leading beyond historical precedence are rising. For improving hazard assessment of potential rock-ice avalanches, their mobility is a critical factor. In this contribution we try to unravel driving factors for the mobility of large rock-ice avalanches by synthesizing results from physical laboratory experiments and empirical data from 64 rock-ice avalanches with volumes >1x106 m3 from glacierized high mountain regions around the world. We systematically assess the influence of avalanche volume, water and ice content, low-friction surfaces, and topography on the apparent coefficient of friction (as a measure of mobility). In laboratory experiments we found granular ice in the moving mass to reduce bulk friction up to 20% while water led to a reduction around 50% for completely saturated material compared to dry flows. Evidence for the effects of water as a key driving factor to enhance mobility was also found in the empirical data while the influence of the ice content could not be confirmed to be of much relevance in nature. Besides liquefaction, we confirm that mobility increases with volumes and found that frictional surface characteristics such as flow paths over glaciers are also dominant variables determining mass movement mobility. Effects of the topography along the flow path as well as channeling are assumed to be other critical factors. The results provide an empirical basis to roughly account for different path and flow characteristics of large rock-ice avalanches on the way to find appropriate ranges for friction parameters for scenario modeling and hazard assessments.