Impacts of Droughts and Heatwaves across the Western United States
Extreme events such as droughts and heatwaves are expected to become more frequent and severe with warming temperatures across the western United States (WUS). Throughout the WUS, large populations rely on snowmelt for a range of uses (e.g., agricultural irrigation, drinking water). Extreme events that contribute to a declining snowpack, facilitate rapid melt, and promote higher sublimation rates can thereby pose significant challenges for managing water resources. Despite this, questions remain about the interplay of heatwaves, drought, and the snowpack. Using multi-decadal historical records of hydrometeorological and snowpack variables (e.g., air temperature, precipitation, snow water equivalent), we investigate links between the land and atmosphere in snow-dominated areas. In particular, we characterize heatwaves, droughts, and the changing snowpack through case studies to better understand drivers of snow loss triggered by one or both of these extremes and the associated impacts. We also quantify the melt rate, timing, and volume of snow water equivalent loss across important hydrological basins of the WUS. Understanding the complex interactions of the drivers of snowpack change from extreme events is critical for sustainably managing our future water resources.