In 1990, a Winter Use Plan was completed for Yellowstone National Park (YNP), Grand Teton National Park (GTNP), and the John D. Rockefeller, Jr., Memorial Parkway (the Parkway). In 1994 the National Park Service (NPS) and U.S. Forest Service began work on a coordinated interagency report on Winter Visitor Use Management. This effort was in reaction to an earlier than expected increase in winter use. The 1990 Winter Use Plan projected 143,000 visitors for the year 2000. In 1992-93 winter use in YNP and GTNP exceeded this estimate.
United States, Department of the Interior, National Park Service, "Winter Use Plans Final Environmental Impact Statement Volume I for the Yellowstone and Grand Teton National Parks and John D. Rockefeller, Jr., Memorial Parkway" (2000). Final Environmental Impact Statements (WY). Paper 14.