Interstate 90 to get numerous wildlife crossings built near Snoqualmie Pass

Building the huge Interstate cut a swath through the wildlife rich mountains and foothills, and over time the wildlife impact of I-90 has grown-

Interstate 90 is a vital transportation corridor from the Seattle area eastward across the northern Cascade mountains, but the magnitude of the gash has served to bisect wildlife populations and cause thousands of accidents, many deaths, over the years.  Deer and elk are the most common large animals killed, but every species in the area gets squashed.

27,000 vehicles a day go over Snoqualmie Pass. Many of them are large trucks. From experience, driving the corridor is very tiring.  Traffic moves fast.  Minor mistakes can have very bad consequences.  Moreover, traffic is increasing and the mostly 4-lane interstate is being upgraded to six lanes.

Now after many years, 24 wildlife crossings are planned in a 15-mille area adjacent to the high point, Snoqualmie Pass.  The Washington State Department of Transportation (WSDOT) is still mostly in the planning state, however, the first 5-miles of the project has received funds to construct. The project includes both overpasses — bridges with vegetation and underpasses.  Experience on other busy highways with constructed wildlife passages shows that both kinds of passage are necessary because some animals have a strong preference for one or the other. So some animals just won’t use an underpass or an overpass.

Here is one of a number of similar stories published in the last week on the project. Wildlife overpasses planned at Snoqualmie Pass. By Pat Muir. Yakkima Herald-Republic and republished in the Seattle PI.



  1. Savebears Avatar

    This is an important story, I am glad to see Washington move this way, I have personally witnessed the effect on Hwy 93 south and it is dramatic on how things have changed.

    Ralph, thanks for bringing this back up again, these are real world solutions that do make a difference in this human dominated world.

  2. Daniel Berg Avatar
    Daniel Berg

    I drove over Snoqualmie last night and I agree that it is tiring to drive over at night. It has been in a habitual state of construction over the last few years at one point or another from east of lake Keechelus up to about the summit. You can drive 70 MPH over that pass and still have the majority of traffic cruising right past you. Combine heavy rain with large trucks and it can feel downright treacherous. I would not want to be an animal trying to cross I-90 anywhere up there.


Dr. Ralph Maughan is professor emeritus of political science at Idaho State University. He was a Western Watersheds Project Board Member off and on for many years, and was also its President for several years. For a long time he produced Ralph Maughan’s Wolf Report. He was a founder of the Greater Yellowstone Coalition. He and Jackie Johnson Maughan wrote three editions of “Hiking Idaho.” He also wrote “Beyond the Tetons” and “Backpacking Wyoming’s Teton and Washakie Wilderness.” He created and is the administrator of The Wildlife News.

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Ralph Maughan