I-90 - Snoqualmie Pass East - Avalanche Structures Final Supplemental Environmental Impact Statement and Record of Decision

The Federal Highway Administration and the Washington State Department of Transportation approved environmental documentation for the I-90 Snoqualmie Pass East project , giving the contractor the green light to build two new elevated bridges in place of the existing snowshed.

This design change came after several months of collaboration between WSDOT and contractor, Guy F. Atkinson Construction. When complete, the new bridges will take traffic up and over a series of engineered avalanche paths designed to direct future sliding snow, rock and debris between the piers and towards Keechelus Lake.

Replacing the snowshed with bridges represents a change from the original plan in the 2008 Final Environmental Impact Statement, which resulted in the selection of a new, expanded snowshed.

Construction of the bridges began in 2014 as part of Phase 1 of the 15-mile I-90 Snoqualmie Pass East project.

These files are in PDF format and you must have a free copy of Adobe® Reader® installed on your computer to view these files.

You can view printed copies of the Final Supplemental EIS and Record of Decision at the South Central Region Office in Union Gap, the Federal Highway Administration Olympia office, or at the following libraries:

  • WA State Library
  • Cle Elum Library
  • Ellensburg Library
  • Central WA University Library
  • Seattle Public Library (downtown branch)
  • King County Branch Libraries:
  • Bellevue Regional
  • Issaquah
  • Lake Hills
  • Newport Way
  • North Bend