Climate warming response of mountain lakes affected by variations in snow

Our objectives were to determine how temperatures in mountain lakes respond to changes in climate and to characterize how their responses are mediated by landscape or lake morphometric factors. Our analysis combines the use of high‐frequency climate and lake temperature data from 1983 to 2016 in a high‐elevation catchment in the Sierra Nevada of California with summer water temperature data from a set of 18 additional lakes scattered throughout the range. Average annual air temperatures warmed at 0.63°C decade−1, but variation in lake temperature was driven primarily by amount of precipitation as snow. By regulating the duration of ice cover and volume of inflowing spring snowmelt, variation in snowpack size accounted for 93% of variation in summer epilimnetic temperatures. The effect of snow on lake temperatures was mediated by variation in elevation and lake depth at landscape scales, creating a predictable mosaic of lake sensitivities to climate warming.