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North Cascades Highway SR-20 Avalanche Atlas

Description: The Avalanche Atlas catalogs details of snow avalanche activity along the North Cascades Highway, SR-20, between Newhalem on the west side of the Cascade Mountains and Mazama on the east side. Data contained herein have been collected during summer and winter reconnaissances in 1970 and 1971 under a contract between the Washington State Highway Department and the University of Washington. Compilation of this Atlas completes the first phase of a planned three-year study of avalanche problems and control methods on the highways of the State of Washington. Other work under this first phase is detailed in a separate Summary Report.

  • Date Published: June, 1971
  • Publication Number: WA-RD 8.2
  • Last Modified: July 11, 2007
  • Authors: E.R. LaChapelle, C.B. Brown, R.J. Evans.
  • Originator: University of Washington. Geophysics Program; University of Washington. Dept. of Engineering.
  • # of Pages: 206 p., 9,457 KB (PDF)
  • Subject: Atlases, Avalanches, Forecasting, Hazards, Highway maintenance, Mountain roads, Mountains, Passes (Mountains), Reconnaissance, Roadside hazards, Snow, Snow and ice control, Snow removal, Terrain evaluation, Topography, Winter maintenance.
  • Keywords: Artillery fire, avalanche control, avalanche paths, avalanches, Cascade Range, snowsheds, snowslides, North Cascades Scenic Highway (Wash.), SR 20.
  • Related Publications: Avalanches on the North Cascade Highway (SR-20), (WA-RD 8.1).
    Avalanche Studies (1971-1972), (WA-RD 8.3).
    Methods of Avalanche Control on Washington Mountain Highways: Third Annual Report, (WA-RD 8.4).
    Methods of Avalanche Control on Washington Mountain Highways: Interim Report (Fourth Annual Report), (WA-RD 8.5).
    Methods of Avalanche Control on Washington Mountain Highways, (WA-RD 8.6).
    Avalanche Atlas. Part 1. Chinook, Cayuse, White and Snoqualmie Passes, (WA-RD 8.7).
    Avalanche Atlas. Part 2. Stevens Pass and Tumwater Canyon, (WA-RD 8.8.).

This abstract was last modified April 29, 2008