Effects of climate change on the intensity and frequency of heavy snowfall events in the Pyrenees

The intensity and frequency of heavy snowfall events in the Pyrenees were simulated using data from the HIRHAM regional climate model for a control period (1960–1990) and two greenhouse emission scenarios (SRES B2 and A2) for the end of the twenty-first century (2070–2100). Comparisons between future and control simulations enabled a quantification of the expected change in the intensity and frequency of these events at elevations of 1,000, 1,500, 2,000 and 2,500 m a.s.l. The projected changes in heavy snowfall depended largely on the elevation and the greenhouse gas emission scenario considered. At 1,000 m a.s.l., a marked decrease in the frequency and intensity of heavy snowfall events was projected with the B2 and A2 scenarios. At 1,500 m a.s.l., a decrease in the frequency and intensity is only expected under the higher greenhouse gas emission scenario (A2). Above 2,000 m a.s.l., no change or heavier snowfalls are expected under both emission scenarios. Large spatial variability in the impacts of climate change on heavy snowfall events was found across the study area.