Firefighters were making good progress today on a 40-acre blaze burning not far from the Teton Park Road in the heart of Grand Teton National Park, according to park officials.

The Cathedral Group Fire, which was reported Tuesday evening, had covered just a dozen acres Wednesday. However, good burning conditions in the forest of conifer and aspen helped push the blaze to 40 acres by this morning. As of mid-day today fire bosses said they had achieved a containment line around roughly half the fire, mainly along the western flank.

Roughly 60 firefighters, aided by helicopters providing water drops, were on the fire, park officials said. They were able to establish hand lines around the western and northwestern flank of the fire, and firefighters also established a network of hose lines, using several small ponds in the Boulder City area as sources for pumping water to hot spots, they added.

With the progress made on the fire lines, trail and campsite closures that were enforced Wednesday were lifted. The only remaining closure today affected the Cathedral Group turnout -- which was being used for staging of fire and helicopter operations -- and the Boulder City off-trail area. All hiking trails, backcountry campsites and park roads are open to public use, the park said.

Rangers were trying to determine the cause of the fire, which was burning about a quarter mile north of the Cathedral Group turnout on the Jenny Lake scenic loop road. Park officials asked that anyone who was in the vicinity of an off-trail area called Boulder City, and who can provide information about this fire, call the Teton interagency fire-reporting line at 307-739-3630.