Based on hydrological model simulations and a new snowmelt tracking algorithm, we show that 53% of the total runoff in the western United States originates as snowmelt, despite only 37% of the precipitation falling as snow. In mountainous areas, snowmelt is responsible for 70% of the total runoff. By 2100, the contribution of snowmelt to runoff will decrease by one-third for the western U.S. in the IPCC RCP8.5 scenario. Snowmelt-derived runoff currently makes up two-thirds of the inflow to the region’s major reservoirs. We argue that substantial impacts on water supply are likely in a warmer climate.
2017), How much runoff originates as snow in the western United States, and how will that change in the future?, Geophys. Res. Lett., 44, doi:10.1002/2017GL073551., , , , and (