Rocky Mountain, Sequoia, Saguaro, Yellowstone and Yosemite national parks all were dealing with wildfires Monday, as was Point Reyes National Seashore, though a potent cold front sweeping down from Canada could bring some relief for firefighters in Rocky Mountain and Yellowstone.

The National Park Service has closed the Silver Bridge that crosses the Colorado River at the bottom of Grand Canyon National Park to all foot traffic due to unspecified structural safety concerns. The bridge crosses the river along the Bright Angel Trail near Phantom Ranch.

When John D. Rockefeller Jr. went to work constructing a 45-mile network of carriage roads at Acadia National Park, he envisioned bucolic paths where riders and horse-drawn carriages could travel away from motorized vehicles. Today, however, riders on legal, and illegal, motorized bikes on those roads are spooking and even harassing horses that pull visitors serenely through the park.

A small plane crashed in the rugged backcountry of Sequoia National Park in California, claiming the lives of two on board, the National Park Service said Saturday.