The Avalanche Atlas is a two part compilation of snow avalanche activity affecting Washington State highways. Part one catalogs details of snow avalanche activity along Chinook, Cayuse, White and Snoqualmie Passes; part two details snow avalanche activity along Stevens Pass and Tumwater Canyon. The Atlas includes descriptive details, historical records, photographs, maps and drawings for each avalanche area.
Part 1, Chinook, Cayuse, White and Snoqualmie Passes has been compiled by several people working in the field. A preliminary survey was made in 1971 by Ray Leonard. Data for Chinook, Cayuse and White Passes were subsequently compiled in 1973 by Norman Wilson and Patti Olson. Data for Snoqualmie Pass were furnished by Al Bennett and others in the Department of Highways. Many persons in the Department maintenance crews furnished historical details and recollections. John Dalle-Molle of the National Park Service was especially helpful with information about Cayuse Pass. Final compilation, editing and field check were by Edward R. LaChapelle. Edward R. LaChapelle, Colin B. Brown and Roger J. Evans are Co-Principle Investigators