Somewhat favorable weather conditions -- low winds, temperatures in the 70s, 20-some percent humidity -- are helping firefighters in their efforts to contain the Beach Fire in Yellowstone National Park.

The fire, which was spotted a week ago burning in a forest of sub alpine fire about 7 miles west-southwest of the Bridge Bay Campground, is holding at roughly 520 acres, fire bosses reported late Friday. Containment lines have been built around 43 percent of the fire's footprint, they said.

The fire is burning in the backcountry several miles away from any roads trails, campgrounds, and lodging. All park roads, entrances and facilities are open. No trails or backcountry campsites are impacted by the fire. When actively burning, smoke from the Beach Fire may be visible for several miles.

Nearly 300 firefighters are battling the flames. On Saturday their strategy was to complete a fire line from the western and northern perimeters of the fire and continuing mop-up operations on the south/southwest boundaries, fire bosses said.

"Additionally, firefighters will be working areas that are still holding heat as well as gridding for any small spot fires outside the perimeter of the fire. Aerial support will continue bucket operations to cool any hot areas near the northeastern corner and western fire perimeters," they added.