MULTIMODAL SENSOR FUSION AND OPERATIONS RESEARCH TECHNIQUES FOR REAL-TIME FLASH-FLOOD EARLY WARNING AND EMERGENCY RESPONSE: A REVIEW

Abstract

Flash floods are among the deadliest natural hazards because they typically develop within hours of the triggering event, frequently leaving disaster managers with lead times of only minutes to a few hours. This paper reviews the principal technical building blocks that underpin modern flash-flood early-warning and response platforms: satellite and radar-based flood mapping, in-situ hydrometric telemetry and sensor-fault detection, kinematic and hydrodynamic wave-routing models, and operations-research (OR) methods for emergency resource allocation. This review focuses in particular on a common weakness in operational systems, namely the tendency to interpret the sudden loss of a river-gauge signal as benign downtime rather than as possible evidence of station destruction during a flood peak. The paper also surveys evacuation-behaviour and loss-of-life models used to quantify the human benefit of earlier warning, and discusses the reproducibility problems that arise when historical disasters are used to benchmark such systems. The review concludes by outlining open research problems in cross-agency data standardisation, real-time computational tractability, and the coupling of physics-based and data-driven forecasting.