New Wilderness in the North Cascades: Thunder Creek Valley

A hiker enjoys the views of Thunder Creek.

National Park Service

Did you know that the only new Wilderness designated in the U.S. during the past year is in the North Cascades? It’s true.

And I was fortunate enough to backpack through this exceptional area in the summer of 2005, enjoying a lovely lunch on a bridge overlooking roaring Thunder Creek.

On September 14, 2012, Secretary of Interior Ken Salazar added 3,559 acres of land managed as part of the North Cascades National Park Complex to the Steven Mather Wilderness. The 1988 Washington Parks Wilderness Act created the Steven Mather Wilderness Area and identified some sections as “potential wilderness,” which could be designated administratively as wilderness if future plans for use were determined to be compatible with Wilderness designation.
The lush Thunder Creek valley affords over 6 miles of creek side hiking through low-elevation old-growth from an accessible trailhead out of Colonial Creek Campground.  In his book, Day Hiking North Cascades, featured trails guru Craig Romano calls Thunder Creek “one of the deepest, wildest, and most accessible wilderness valleys in the North Cascades National Park Complex.” Thunder Creek itself has a stunning color because it carries debris called “rock flour” that originates from the glacial headwaters of this hanging valley. Just another reminder that the North Cascades is the most glaciated area in the lower 48 states.
In the case of the Thunder Creek valley, just off the turquoise-blue southern edge of the Thunder Arm of Diablo Lake, Seattle City Light had been reserving the potential to utilize the area for hydropower production. With a 2008 decision abandoning that potential, the door was opened for this magnificent area to be added to our National Wilderness System. The Wilderness Society and several of our conservation and recreation partners in Washington have been supporting this designation since 1988 and most recently advocated for it through the Ross Lake National Recreation Area General Management Plan.
We are proud to celebrate this achievement with the National Park Service and Department of Interior.
The new wilderness includes three campsites and one horse campsite, as well as a mile-long Thunder Woods interpretive loop trail.
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