Data in this data release contain Model input and output for simulations used to estimate the amount of tephra that could fall on the Hanford nuclear waste repository. The results of that study were written up in the report: Mastin, L.G., Van Eaton, A.E., and Schwaiger, H.F., 2020 A Probabilistic Assessment of Tephra-Fall Hazards at Hanford, Washington, from a Future Eruption of Mount St. Helens, U.S. Geological Survey Open-File Report 2020-XXXX, 54 pp. That study cites supplementary tables and files, which are included in this data release. The supplementary data are contained in three zip files: 1) Main_report_supplementary_tables.zip contains the supplementary tables cited in the main report, along with a readme file. 2) Appendix_A_supplementary_files.zip contains the supplementary files cited in Appendix A. 3) Appendix_B_supplementary_tables.zip contains supplementary tables cited in Appendix B.