… Rock glaciers are slow-moving masses of rock debris and ice that flow downhill the same way that glaciers do, but they are covered by a thick layer of rock and boulders that can easily be mistaken for stable ground. There are at least 1,500 active rock glaciers across the western U.S., and they’re important. That’s because while the icy white glaciers people typically picture have been shrinking and even disappearing, our new study shows that rock glaciers and their frozen water are remaining mostly stable despite rising temperatures. … The result is that rock glaciers continue to provide meltwater for streams in summer as they always have. … Because of this, streams fed by rock glaciers have emerged as potentially critical climate refugia – places likely to stay cooler while everything around them warms – for cold-water wildlife in high-mountain ecosystems.