An inversion that was holding smoke from a backcountry fire in Yellowstone National Park close to the ground prompted officials today to extend the closure of a section of the park's Grand Loop Road.

While most folks head to Mammoth Cave National Park with the intent to spend most of their time underground, during a recent visit the weather was delightful we decided to spend as much time above ground hiking the trails and limit our tours underground to two guided trips.

Dry forests and grasslands, low humidity levels, and gusty winds have prompted officials to raise the fire danger in Grand Teton National Park and the surrounding Bridger-Teton National Forest in western Wyoming to "high," a marker that fires can start easily and spread quickly.

Come Saturday morning, thousands of Americans will head to public lands across the country to pull invasive species, plant trees, clear trail, paint, mulch and build bird boxes. Volunteers will contribute millions of dollars in improvements to public lands ranging from local schoolyards to national forests. As a supporter of the National Park System, we invite you to volunteer this Saturday for National Public Lands Day.