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Save the Pumice Plain

The Cascade Forest Conservancy, along with researchers, concerned individuals, and other conservation organizations, is opposing a proposed project involving the construction of a road through the Pumice Plain in the Mount St. Helens National Monument.

The Pumice Plain


The Pumice Plain is a 6 square mile area situated between the north side of Mount St. Helens and Spirit Lake. This landscape was created during the 1980 eruption by pyroclastic flows that buried the land under hundreds of feet of superheated volcanic debris. Nothing survived.

Yet, more quickly than previously thought possible, life has come back. 40 years after the eruption, the Pumice Plain is still a rugged, windblown landscape but is now rich with insects, plants, and animals, all illustrating the stubborn resilience of life. The area’s inclusion in the Mount St. Helens National Monument and designation as a protected Class I Research Area has provided scientists and researches with an unparalleled opportunity to study the formation of brand-new ecosystems as never before. The scientific insights gained here have transformed our understanding of how ecosystems form and new discoveries are still being made.


The Proposed Project

The threat facing the Pumice Plain is a component of a larger project proposed by the U.S. Forest Service to maintain infrastructure around nearby Spirit Lake. The same eruption that created the Pumice Plain also buried Spirit Lake’s only outlet, leaving rainwater and snowmelt flowing into the lake with nowhere to go. If the water rose to a high enough level, it could destabilize the earthen dam holding the waters back. In a worst-case scenario mudslides and floods could cause serious harm to downstream communities. The Army Corps of Engineers constructed a tunnel to provide the lake waters with somewhere to go. However, the infrastructure and tunnel are in need of maintenance and repairs and an intake gate need to be replaced to continue to function correctly.

The project proposal also includes drilling core samples from the debris blockage to assess its stability. Transporting heavy drilling rigs to the site seems to be one of the main reasons a road across the Pumice Plain is being proposed.

Cascade Forest Conservancy, along with the scientists and individuals opposing the current proposal all fully support work to maintain and repair public safety infrastructure. However, we do not believe the project as currently proposed is the best way to protect downstream communities. Studies using ground-penetrating radar can yield almost the same data as core sample drilling and experts have called the stated need for new core samples premature. Additionally, the current plan has not adequately explored alternatives that protect the places we can’t afford to lose. The agency has not taken the time to fully understand the full implications of a road and is trying to push forward without completing an Environmental Impact Statement (EIS) – an in-depth environmental analysis legally required for a project like this one.

An in-depth explanation of our objections to the current proposal can be found in official objections submitted to the agency, available HERE.

Impacts of a Road

If built the road would:

  • Close the world-famous Truman Trail, which offers hikers the opportunity to experience the power of a Cascadian Volcano and the resilience of life up-close as nowhere else can.
  • Disrupt and displace animal populations returning to the area.
  • Risk introducing invasive species into a pristine natural laboratory.
  • Destroy or disrupt ongoing studies and introduce changes to the landscape that could prevent future discoveries from being made.
  • Cross over five, one-of-a-kind, newly formed watersheds in the area, clogging newly formed streams with sediment runoff, threatening the health of nearby Spirit Lake.

Get Involved

The official comment and object opportunities for this project have passed, but you can still help protect the Pumice Plain!

Help us spread the word! Sharing this article with your friends, or these images for social media will help save this irreplaceable area.

Go see the Pumice Plain for yourself. Hike the Truman Trail. Tell people about the area and share your photos on social media with the hashtag #SaveThePumicePlain

Make a donation to Cascade Forest Conservancy. We will continue to advocate for public-safety solutions that cause the least harm possible to wild and protected areas. Your donation helps us continue this important work.