  In many coastal communities, the risks driven by storm surges are motivating
substantial investments in flood risk management. The design of adaptive risk
management strategies, however, hinges on the ability to detect future changes
in storm surge statistics. Previous studies have used observations to identify
changes in past storm surge statistics. Here, we focus on the simple and
decision-relevant question: How fast can we learn from past and potential
future storm surge observations about changes in future statistics? Using
Observing System Simulation Experiments, we quantify the time required to
detect changes in the probability of extreme storm surge events. We estimate
low probabilities of detection when substantial but gradual changes to the
100-year storm surge occur. As a result, policy makers may underestimate
considerable increases in storm surge risk over the typically long lifespans of
major infrastructure projects.
