Both the North and South American monsoon regions receive more than 50% of their total annual precipitation during local summer.  Much of this precipitation is delivered not by steady, continental-scale winds, but by transient disturbances that also produce hydrological extremes, with large impacts on societies and ecosystems. Extreme dry events can affect global food security (agriculture and irrigation), as well as electricity generation and demand (water and energy). Extreme wet events can cause property damage and impact human health through landslides and the proliferation of waterborne diseases. In this session, we invite submissions on all aspects of the variability and predictability of extreme events in the North and South American monsoon regions. We especially welcome papers focusing on interannual and intraseasonal variability in the frequency of hydrological extremes, impacts of water transport and recycling on extreme precipitation events, the role of land surface processes on extreme events, mechanisms of extreme variations in the timing of monsoons, the dynamics of synoptic-scale disturbances, and the prediction of extreme events on subseasonal to seasonal (S2S) timescales. The focus of the session includes tropical cyclones that make landfall in the North American monsoon region or that initiate other disturbances affecting rainfall over land (such as Gulf of California moisture surges).

This session will highlight initial analyses and the assessments of the health impacts from the devastating hurricane season of 2017, with a focus on interactions between healthcare and municipal infrastructure, housing and human and animal health.  Immediate and delayed impacts, cascading power failure and heat waves, infectious and chronic diseases, loss of access to care and exposure to harmful chemicals and pathogens are all relevant subjects.  Talks highlighting innovative ways of obtaining data or implementing solutions are most welcome.