Heavy rainfall in China's Yangtze River basin as a result of the longest and strongest El Niño event for 65 years has led to severe flooding and economic losses of almost US$10 billion. Massive investments in flood defences after the 1998 deluge, which killed more than 4,000 people, proved inadequate. New tactics could help boost China's flood control.

Alongside better levees, enlarged reservoirs and improved early-warning systems, disaster-risk analysis can guide strategies for managing disasters (see S. L. Cutter et al. Nature 522, 277–279; 2015). Disaster risk depends on the degree of hazard, exposure and vulnerability (Y. Zhou et al. Risk Anal. 34, 614–639; 2014).

Accurate hazard assessment calls for a better understanding of extreme weather events and their rising frequency and intensity. Exposure calculations should factor in different population densities across the region. And vulnerability estimates should note the efficacy of early-warning systems and the resilience of local infrastructure (J. Birkmann et al. Nat. Hazards 67, 193–211; 2013).

Speedy access to and effective dispersal of reliable disaster-risk information and of disaster-relief professionals will help to prevent and mitigate catastrophic outcomes, including secondary disasters such as landslides.