Simulations of climate by global climate models provide one basis for examining possible future climate change in a region. Despite the coarseness of the global models' resolution, important aspects of regionally averaged climate are well simulated, including temperature, the sharp seasonality of the region's precipitation, and the observed 20th century warming of 1.5F. We use output from several climate models to drive the VIC macro-scale hydrology model, which has been implemented over the Columbia River Basin at 1/8 degree horizontal resolution. The range of climate scenarios from the climate models provides a range of possible future streamflows for selected decades, underscoring and quantifying the risk that a warmer climate poses to the region's snowpack and summer water supply. A reservoir operations model (ColSim), can be used with VIC output to quantify the impacts of climate change on the reliability of a wide range of system objectives, and shows that even with fairly dramatic climate changes, one or two top-priority objectives can be protected, but at significant cost to other objectives. The UW Climate Impacts Group has encouraged water resource managers and policymakers to consider climate change in long-term plans, and has had some early successes.