A forest fire in the San Juan National Forest triggers an air quality warning due to heavy smoke

Thick smoke from a wildfire in the San Juan National Forest northeast of Dolores has prompted authorities to issue an air quality warning for southwest Colorado, but firefighters on the scene say they have the blaze under control.

The Spruce Creek fire was likely sparked by lightning on May 14, but overnight the fire doubled in size and now covers more than 18 square kilometers. More than 150 firefighters are working to contain the blaze, which is devastating trees, shrubs and ground vegetation.

Crews have not yet been able to contain the fire, but the Rocky Mountain Area Coordination Center – a federally run consortium of land managers that coordinates wildfire response – reports that firefighters on the scene have cut down trees and dug firebreaks to contain the spread .

No evacuations were ordered and no homes or buildings were damaged, but the U.S. Forest Service has closed roads near the fire.

US Forest Service

The Colorado Department of Public Health and Environment has warned that smoke from the wildfire could reach Telluride, Ouray, Silverton, Lake City, Creede and other areas near the national forest. It is advising people in the area to limit their outdoor activities, especially very young and elderly residents or those with heart or respiratory conditions. The warning says smoke could linger in the region until Friday morning.

The rapid spread of the Spruce Creek fire is due in part to a decision by firefighters and forestry officials earlier this week to allow the fire to spread in a controlled manner to reduce the long-term wildfire threat.

Mike DeFries, spokesman for the Southwest Area Incident Management Team, said firefighters are using forest roads, terrain and rock outcrops to encircle the fire and give it a chance to burn off “a lot of old ground fuels that have become denser over the decades.”