Tracing the pathways from drought to wildfire: Compound and cascading hot-dry hazard processes in a Mediterranean climate

This study examines the interactions among drought, heatwaves, and wildfires in Türkiye using compound and cascading hazard frameworks. The aim is to assess how these hazards co-occur or sequentially evolve over time and to quantify their relationships with observed wildfire events. The analysis is based on daily ERA5 reanalysis data covering the period 1970–2025. Compound hazards were identified as the simultaneous exceedance of multiple hazard thresholds on the same day, whereas cascading hazards were defined as sequential hazard processes occurring within specified time windows prior to wildfire events. Fire-day matching results show that 14.55% of the 1,863 recorded wildfires are associated with same-day compound conditions, indicating a limited role of simultaneous hazard interactions. In contrast, when antecedent cascading processes are evaluated using predefined temporal windows, their explanatory capacity increases progressively from 5.05% (7-day) to 22.28% (30-day), highlighting the importance of cumulative preconditioning over multi-week timescales. Across all temporal windows, the heatwave-wildfire (HW→WF) sequence emerges as the dominant cascading pathway, while other configurations contribute only marginally. The discriminatory ability of cascading indicators was evaluated using Receiver Operating Characteristic (ROC) and precision-recall analyses. For the HW→WF indicator, the area under the ROC curve (AUC) increases from 0.67 (7-day) to 0.74 (30-day), indicating improved performance with longer antecedent periods. In contrast, the DR→HW→WF indicator exhibits consistently lower performance, with AUC values ranging between 0.56 and 0.58 across all time windows. Precision-recall results show a similar pattern, although overall AUPR values remain low. Overall performance remains moderate, reflecting the rarity and spatial heterogeneity of wildfire events. The results indicate that wildfire occurrence in Türkiye is more strongly linked to antecedent climatic processes than to same-day conditions alone. However, these relationships represent proxy-based statistical associations and temporal sequencing rather than direct physical causality for individual fire events. The findings highlight the importance of integrating compound and cascading hazard perspectives into wildfire risk assessment and early warning systems. By emphasizing the cumulative and sequential nature of drought-heatwave-wildfire interactions, this study provides a transferable framework for understanding increasingly complex wildfire risks under Mediterranean-type climate conditions.