Authors
Nels Bjarke (CIRES,Western Water Assessment), Elizabeth Payton (CIRES,Western Water Assessment), Benet Duncan (CIRES,Western Water Assessment), Ben Livneh (CIRES,Civil, Environmental, and Architectural Engineering), Samba Thota (Civil, Environmental, and Architectural Engineering)
Abstract
Multi-year dry periods are becoming more frequent and severe across the Western United States as regional temperatures rise. This shift raises a key question for drought experts, water managers, and ranchers alike: when dry soils and low runoff become the norm, how do we define a drought? This poster presents our progress on a web tool designed to help users explore how droughts are classified and how climate change has reshaped our understanding of historically significant droughts in the West. Using ERA5 reanalysis and ERA5-Land simulations from 1950 to 2024, we show that recent climate trends have influenced classifications of both atmospheric and land-surface droughtsâbased on precipitation, soil moisture, evapotranspiration, and runoff. We also examine the potential socioeconomic impacts of adjusting drought classification frameworks, emphasizing the importance of accounting for non-stationarity. Specifically, we show how shifting the reference period for drought metrics could significantly affect disaster relief payments to agricultural producers in the Western Water Assessment region (Colorado, Wyoming, and Utah).