Predicting weather extremes and water resources in the climate transition: a focus on America’s headwater region

Water resources in America’s headwater region (mainly Wyoming and Colorado) are under significant threat in a globally warming climate. The key threats are a shift from snow- to rain-dominated regimes over mountains, higher rates of evaporation, and simultaneously increasing frequencies of droughts, wildfires, and flooding events. These changes will elevate risks to water availability and to the normal functioning of watersheds and ecosystems. They will diminish the quality of natural resources that underpin regional social and economic stability and quality of life. This presentation will show-case site-specific projections of long-term changes in climate parameters, especially precipitation, seasonal snowpack, and extremes: flooding events and droughts. We use bias-corrected, dynamically downscaled CMIP6 GCM output, at sufficient resolution to represent mountains and cold-season orographic precipitation. We will discuss how this information is made openly accessible and used by decision-makers and communities to navigate uncertainty and to co-create actionable science.