Material convergence is the influx of goods and supplies toward an impacted area after disaster [@wachtendorf2010].

The term matters because incoming supplies can solve urgent problems while also creating reception, storage, sorting, and distribution bottlenecks. Wachtendorf and coauthors show that Katrina revealed how catastrophic conditions intensify this problem and force responders to manage convergence actively rather than assume that more goods always mean better relief [@wachtendorf2010].