Civil Defense exercise at Lake Youngs with Supt Morse, Mayhew and others. prints and negatives LHB - 7-16-1954 and 7-22-1954 - 03817-03826, 1954 - 1954, Box: 2, Folder: 03817. Water Department Photographic Negatives, 8200-13. Seattle Municipal Archives. https://leglas100/finding-aids/repositories/2/archival_objects/194056 Accessed June 02, 2026.