Rampant wildfires created unseen danger in parks: ‘Seemingly flat earth can be hollow’

An unexpected danger is being linked to the rampant wildfires that destroyed millions of acres over the summer.

In some cases, areas below the surface also caught fire and burned without anyone knowing, the U.S. Forest Service says.

“Seemingly flat earth can be hollow underground after fire has burned through root systems, creating treacherous pits and holes,” officials with Gifford Pinchot National Forest in Washington state wrote Dec. 12 on Facebook.

The post is intended as a warning to hikers who might try entering these forbidden zones at the worst possible time.

“Winter weather brings extra safety hazards to burned areas — trail systems are often unnavigable, and wayfinding can be difficult .... Hikers should avoid this area, as it poses a risk to their own safety, and the safety of search and rescue crews who are sent out in response!”

Gifford Pinchot National Forest, about three hours southeast of Tacoma, was home to the Big Hollow Fire over the summer. It burned about 24,000 acres and left behind “unstable soils, falling rocks, (and) fire-weakened trees,” the forest service reported in November.

Big Hollow was one of 52,934 wildfires in 2020 that burned 9.5 million acres in the U.S., nearly double the acreage lost in 2019 to wildfires, the National Interagency Fire Center reports.

Root system fires are a dangerous part of the aftermath, experts say.

“A root fire is a fire that burns underground along the root system of a tree,” Sectionhiker.com reports. “It’s a very dangerous form of fire because the fire can smolder for months underground, long after the surface part of the fire has been extinguished. Root fires can also travel underground and resurface some distance from their point of origin.”

This story was originally published December 14, 2020 at 1:56 PM with the headline "Rampant wildfires created unseen danger in parks: ‘Seemingly flat earth can be hollow’."