Large uncertainties in early warning of debris flows in southeastern Tibet increased by climate change

Climate change is fundamentally altering debris flow triggering mechanisms in high-altitude regions, challenging the reliability of traditional early warning systems. We analyzed 214 debris flow sites in Bomi County, southeastern Tibet (1937-2024), integrating field surveys, remote sensing data, and meteorological observations. We evaluated the performance of an Intensity–Duration (I-D) threshold model calibrated on historical data (1950–2000) when applied to recent events (2001–2024), and developed a Temperature-Rainfall dual-parameter model. Our analysis reveals that debris flow frequency increased 7.1-fold from 2001 to 2010 (21 events) to 2011-2020 (150 events). The I-D model showed degraded performance: f false alarm rates increased from 12% to 28% and missed event rates from 8% to 19%. The dual-parameter model demonstrated superior performance (AUC = 0.87 vs. 0.74). We conclude that static, historically calibrated models become increasingly unreliable under warming, necessitating adaptive early warning systems with dynamic threshold adjustment, multi-parameter integration, and explicit uncertainty quantification. Our findings have critical implications for disaster risk management in cryosphere-influenced mountain regions worldwide.