Los Angeles 100-year flood risk

Flood risks in the U.S. have historically been underestimated, particularly with respect to human well-being and within low-wealth and marginalized communities. Here, we characterize a fuller range of risks in Los Angeles, California, using a quantitative framework that intersects flood hazards from rainfall, streamflow, and storm tides with measures of exposure and vulnerability including ethnicity, race, and socioeconomic disadvantage. We find that between 197 and 974 thousand (K) people (median=425K), and between $36 and $108 billion (B) in property (median=$56B), are exposed to flooding greater than 30 cm within the 100-year flood zone, risk levels far above federally defined floodplains and similar to the most damaging hurricanes in U.S. history. These risks are disproportionately higher for non-Hispanic Black and disadvantaged populations, burdening communities that may have greater challenges recovering and reinforcing socioeconomic inequities. Our framework creates opportunities...