Firefighters on Friday battled a 2-acre blaze at the base of Animas Mountain near the 3800 block of Main Avenue.
The fire, which was reported at 4:14 p.m., made a quick run up the mountains eastern slope, but by Friday evening was under control and partially contained, a fire official said.
Smoke was visible from many areas around town, and firefighters from various agencies responded.
U.S. Highway 550 between about 32nd Street and north Animas View Drive was closed Friday evening while three helicopters traversed overhead with buckets of water some carrying several hundred gallons. Traffic was rerouted on county roads.
Fire officials mounted a vigorous attack to keep flames from climbing over the ridge and into more densely vegetated land.
Its a big concern for us to get this shut down before it tops out, said Hal Doughty, deputy fire chief for the Durango Fire & Rescue Authority.
The cause of the wildfire remained under investigation; there has been no lightning within the last week, said Karola Hanks, fire marshal with the Durango Fire & Rescue Authority.
The fire, dubbed the X-rock fire, settled down and was partially contained by 7 p.m. Friday.
Its looking pretty good now, said Craig Goodell, a fire mitigation and educational specialist with the Bureau of Land Management. Its in the shade, and the helicopters have been doing good work.
X-rock is a rock formation west of Highway 550 near northern city limits where rock climbers recreate.
The fire was all or mostly on county property. It was burning through piñon, juniper and Gambel oak brush.
No structures were immediately threatened, but flames came within about a quarter mile of offices occupied by the Colorado Department of Transportation. The building was evacuated.
Local and federal agencies were managing the blaze, which was generating significant smoke but was not crowning, or jumping from treetop to treetop, fire officials said.
Fire officials planned to monitor the burn area Friday night and continue firefighting efforts today.
A red-flag warning has been issued today, meaning the fire danger is high because of warm temperatures and strong winds. Fire restrictions on public lands take effect today.
The X-rock fire came as Durango marks the 10th anniversary today of the Missionary Ridge Fire. The 2002 fire consumed 72,862 acres over 39 days.
Fire officials have said that current conditions are similar to those leading up to that devastating fire. Southwest Colorado is in a moderate drought after the areas below-average snowpack quickly melted this spring.