Droughts, driven by hydrometeorological processes that reduce precipitation and water availability, are extensive natural hazards causing significant socioeconomic impacts worldwide. Southern Alberta, part of the Canadian Prairies, has a history of recurrent droughts, including notable events like the "Dust Bowl" of the 1930s and the 2001–2002 drought, which led to over $5.6 billion in GDP losses in Canada. Effective drought management relies on their monitoring and forecasting based on indices that quantify drought severity, timing, duration, and location. Among the many indices developed, the Standardized Precipitation Index (SPI), Standardized Precipitation Evapotranspiration Index (SPEI), Palmer Drought Severity Index (PDSI), and Reconnaissance Drought Index (RDI) are widely used, each suited to specific conditions and datasets. A index suitable at particular region for particular purpose may not be suitable for other region due to inherent complexity of drought process, and varying geophysical and climatic conditions. This study seeks to identify the most effective drought index for Southern Alberta by comparing four indices against historical drought records and hydrometeorological data from 37 stations over six decades. The intercomparison was assessed using correlation and Cohen’s kappa analysis, while their strength to reflect other aspects of drought was validated by comparing against streamflow and groundwater level data at multiple timescales. Furthermore, the drought condition reflected by the indices were compared against historical drought maps to assess their effectiveness. The findings will contribute to actionable measures for drought preparedness and mitigation in the region.
