• View from Sourdough Mountain Overlook  A view looking down onto Diablo Lake. Photo Credit: NPS/Michael Silverman, 2010.

    North Cascades

    National Park Washington

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  • Lone Mountain Fire - National Park Service Trail Closures

    The Lone Mountain Fire in North Cascades National Park is approximately 5 mi NW of Stehekin in the Boulder Creek drainage. Boulder Creek Trail is closed. More »

  • USFS Access Road and Trail Closures

    The following USFS trails providing backcountry access to the park service complex are closed due to Lone Mountain and Carlton Complex Fires: Twisp Pass, South Creek, Reynolds Creek, War Creek, Summit. The Twisp River Road is closed west of Eagle Creek. More »

Air Quality

Views from Thornton Lakes and Trapper's Peak. Photo Credit: NPS/NOCA Staff

Looking down into a hazy Skagit Valley from Trappers Peak.


Recognizing the value of the fresh mountain air of the North Cascades, Congress designated North Cascades National Park as a Class I area, affording it the highest degree of air quality protection. Unfortunately, the park lies in the path of prevailing westerly winds blowing from rapidly growing urban-industrial and agricultural areas in Puget Sound. The mark of humankind's activity can be found everywhere within the park. Windborne pollutants are deposited on glaciers in the park via precipitation. As the ice melts, water carries the pollutants into the food chain, moving from tiny aquatic insects called macroinvertebrates to fish to land mammals and eventually even back to humans.

Consequently, park managers are cooperatively involved with the US Geological Survey, the National Park Service's Air Resources Division and others to assess air pollution impacts and protect air quality related resources. The air resources management program at North Cascades includes monitoring, research and data dissemination. Pollutants such as particulate matter, ozone, acid deposition, mercury and pesticides have been monitored in the park. The park and cooperators have also studied the impact of those pollutants on visibility, water quality, vegetation and wildlife. Data are used to inform management strategies and regulatory activities that affect park air quality.

Did You Know?

Did You Know?

North Cascades NPSC has over 300 glaciers, more than any other park in the lower 48 states. More than half the glaciers in the 48 states are concentrated in this mountainous wilderness region called the North Cascades.