Assessing and screening flood exposure risks for emergency response

Flood occurrence and intensity changes may increasingly threaten the accessibility of emergency medical services. To investigate this threat, we develop a data-driven framework for assessing flood effects on time-critical ambulance routes, using suspected cardiac arrests Sweden as a test case. We integrate two key datasets: over 117,000 ambulance dispatch records, and seven years of high-resolution modelled hydrological risk data. First, we establish a strategic health access network through algorithmic routing of the empirical dispatch locations and intersect these routes with historical flood risk to derive their long-term exposure profile. We find that the most vulnerable emergency corridors face up to 17% annualised flood risk frequency, or approximately 62 flooded days per year. Second, we perform a risk-centric performance screening to identify specific operational degradation, isolating ambulance routes where real-time flood risk coincided with measurable response delays that exceeded local performance baselines. This screening localises critical operational delay hotspots in emergency services and quantifies delays for flood-exposed routes, with an average delay rate of 82 seconds/kilometre over the municipal median. These delayed ambulance route segments occurred most frequently within urban centres in west and central Sweden (e.g. the cities of Gothenburg and Karlstad) as well as in smaller, geographically diverse and rural areas, such as northern Sweden. Overall, the approach developed and tested here shifts risk assessment from static hazard mapping to dynamic service discontinuity, offering a general tool for prioritising operational planning measures and infrastructure investment through a public health lens to enhance emergency medical response capacity and resilience.