A number of wildfires were burning Saturday across the National Park System, with blazes reported in Bryce Canyon, Olympic, Kings Canyon, and North Cascades national parks, though none were threatening developed areas of the parks.

Mutton Fire, Bryce Canyon National Park

The Mutton Fire burning just about a mile south of Yovimpa Point near the southern end of the park road was estimated at only about 12 acres in size by park officials. It was spotted August 2 after a lightning storm passed through the area.

"Due to its isolated location and the fact that it posed no threats to park resources or visitor safety park officials decided to manage the fire for multiple objectives including returning fire to its natural role in the ecosystem," park officials said.

"Most of the fire activity has been creeping and smoldering in the forest understory with occasional torching of small trees and brush," they added. "Firefighters have been monitoring the fire daily since its start and will initiate management actions including line construction, helicopter water drops and burnout operations when deemed necessary to control its growth."

One impact of the fire has been the temporary closure of the Riggs Spring Trail, park officials said. All other park trails and facilities were open.

Smoke from the Mutton Fire may be visible from the park’s southern viewpoints and area highways but has not been an issue to date. Smoke might settle into low-lying valley areas during evening and early morning hours, they added.

Hopper Fire, Olympic National Park

Lightning also was the cause of the Hopper Fire in Olympic. It was spotted August 5 and showed little activity until Friday, when high temperatures, low humidity, and gusting winds spread the blaze from 2 acres up to roughly 120 acres, park officials said Saturday.

AS with the Mutton Fire in Bryce Canyon, this fire was being managed as a natural process in the park.

"We are continuing to monitor the fire and encourage visitors to safely enjoy the park,” said Olympic Superintendent Karen Gustin.

The Hopper fire is located on Mount Hopper on the east side of Olympic National Park, at the headwaters of the Crazy Creek Drainage and Skokomish River in the Olympic Wilderness. Fire managers plan to monitor the fire as it moves towards natural barriers, including late-melting snow fields to the north and west and Mount Stone to the east, park officials said.

All major trails and park facilities remain open at this time, they added. However, the Mount Hopper Way Trail has been closed. Hikers should be aware they may encounter smoke in the Mount Hopper area and are encouraged to call the park’s Wilderness Information Center (360-565-3100) or visit at http://www.nps.gov/olym for alternative trail suggestions.

Sheep Fire, Kings Canyon National Park

The Sheep Fire in Kings Canyon was approaching 650 acres in size Saturday based upon a helicopter reconnaissance and mapping mission on Friday. The fire is highly visible in Cedar Grove, according to a park release. However, there were currently no threats to life or property.

This fire is located in the southern cliffs above Cedar Grove, one-half mile north of Sentinel Ridge. The fire has continued to back down towards the Cedar Grove Valley as well as spread to the west. Fire behavior includes creeping, backing fire with some isolated active pockets and occasional torching. It was started by lightning on or about July 16th.

Park officials said visitors to the Cedar Grove area should anticipate smoke settling into the valley in the late evening and early morning hours. The Don Cecil Trail in Kings Canyon (from the trailhead at Cedar Grove to the park boundary) was closed for public safety. The trail closure is in effect until further notice.

The Sheep Fire was burning in a mixed conifer forest and at 7,000 feet in elevation, the park reported, adding that there is no recorded fire history within the Sheep Fire perimeter. Recent wildland fires and prescribed fires to the east should limit or slow fire spread in that direction, they said.

Rainbow Bridge Fire, North Cascades National Park

The Rainbow Bridge Fire was started July 29 by a lightning strike. It was burning within the Lake Chelan National Recreational Area of the North Cascades National Park Complex near Stehekin, Washington.

The fire, which was nearly 4,000 acres in size, was being fought by ground crews and water drops from a helicopter. Their goal was to secure a perimeter around the fire and attack any hot spots that flared up, according to officials.

All activities and services to and from Stehekin were open.