A comprehensive monitoring framework is proposed for multimode processes in which mode clustering and mode unfolding are integrated within an adaptive strategy. To start, an aggregated k-means algorithm produces an optimal ensemble clustering solution for a multimode process dataset. Next, a mode unfolding (MU) scheme enables the development of a single principal component analysis (PCA) model for processes operating under multiple desired steady-states (modes). Finally, adaptive strategies for online mode identification and model updating are presented to address the challenges in fault detection in the presence of multiple operating modes. The validity and usefulness of the adaptive MU-PCA based monitoring framework is demonstrated through a study of the Tennessee Eastman benchmark process. (C) 2013 Elsevier Ltd. All rights reserved.