It's fall travel time at Rocky Mountain National Park, but a fire which started about 4:30 p.m. on Saturday caused park officials to close a section of Trail Ridge Road on the west side of the park for about 18 hours. Cross-park traffic resumed Sunday afternoon, with one-lane traffic at the site of the fire.

The "Onahu (on-a-who) Fire," named for a nearby trailhead, was spotted Saturday afternoon, when it quickly went from just 2 acres in size to about 40 acres. The fire was located about three and a half miles north of the Kawuneeche Visitor Center in the southwest corner of the park.

The fire burned on both sides of Trail Ridge Road and forced the temporary closure of the famed scenic drive from Milner Pass, near the mid-point of the road where it crosses the Continental Divide, to the Grand Lake Entrance Station. The closure was prompted by active fire fighting efforts, heavy smoke, and standing dead trees that threatened to fall across the road.

In view of dry conditions and the recent major fire across the mountains near Boulder, Colorado, authorities didn't take any chances with this one. Crews responded from throughout the region and two Hot Shot crews arrived overnight to stop the fire's spread and contain the blaze at 40 acres. Ninety-percent of the fire burned in grass and shrubs. A water-dropping helicopter greatly aided suppression efforts on Saturday.

Ground crews made significant progress Sunday, patrolling for spot fires outside the fire perimeter and laying a hose line around the fire. The fire smoldered all day while fire fighters extinguished everything within 25 feet of the fire line. The fire did not threaten to advance. However, snags—dead, standing trees—remained a threat to fall on Trail Ridge Road and that delayed the reopening of the road from Milner Pass to the Grand Lake Entrance Station.

Just before noon on Sunday, the road was opened to one-lane traffic at the site of the fire, allowing cross-park traffic to flow once again during a beautiful fall weekend.

Crews will return Monday to continue to mop-up the fire, patrol the area, and ensure that the fire doesn't reignite and spread beyond control lines. The only trail officially closed by the fire was the Onahu Creek Trail, near the start of the fire. A cause of the fire was not immediately known.

Rocky Mountain National Park always has fire restrictions in place, but due to current high fire danger, additional restrictions are now in effect. Fires will only be allowed in designated fire grates. Only petroleum-fueled stoves and grills will be permitted in all designated backcountry campsites.

Smoking is prohibited, except within enclosed vehicles, parking lots, or developed areas, such as campgrounds and picnic areas that are cleared of all flammable materials for at least three feet in diameter. Visitors are reminded to properly extinguish all lighted smoking materials. Fireworks are always prohibited within the park. These restrictions are in effect until further notice.

Trail Ridge Road updates are available on the park website or by calling 970-586-1206 during business hours.