The authors thank A. Adams, L. Ball, B. Bloss, L. Bonner, B. Burton, T. Bye, B. Fry, E. Hart, M. Lee, K. Menoza and M. Wisniewski for their invaluable contributions to the data collection effort. The authors thank the Gifford-Pinchot National Forest, Weyerhaeuser, the Washington DNR, Mount Rainier National Park, Port Blakely Tree Farms, Hancock Forest Resources, Pope Resources, West Fork Timber Company, the White Pass ski area and numerous private landowners for land access without which this work would not have been possible. T. Sisson, C. Finn, O. Bachmann, R. Blakely and J. Glen provided valuable discussion and critical input that helped to shape this manuscript. The authors thank R. Blakely and C. Finn for processing the magnetic field data (available at https://mrdata.usgs.gov/airborne/), R. Evans and P. Wannamaker for making the Café MT data publicly available (available at https://ds.iris.edu/spud/emtf) and D. Ramsey for providing Quaternary vent locations. Seismicity is from the Pacific Northwest Seismic Network. This research used resources provided by the Core Science Analytics, Synthesis, and Libraries (CSASL) Advanced Research Computing (ARC) group at the US Geological Survey (USGS). This work was supported by the USGS Volcano Hazards and Mineral Resources Programs and the US National Science Foundation grant EAR1144353 through the GeoPrisms program. Any use of trade, firm or product names is for descriptive purposes only and does not imply endorsement by the US Government.