Crews work to contain wildfire burning in San Juan National Forest in southwest Colorado

Firefighters are working to extinguish a wildfire that broke out in Colorado's San Juan National Forest on Monday.

SJNF staff posted a notice on the national forest's Facebook page just before 5:45 p.m. stating that a fire sparked on the west side of Highway 550 on national forest land and was burning through the Gambel Oak and Ponderosa Pine trees.

In an update Monday night, national forest staff said the fire was burning in steep, rugged terrain. The Los Pinos Fire District constructed a fire line around approximately half of the fire's footprint, which had grown to about 1.5 acres by late Monday night. Officials said dead trees posed a significant threat to the firefighters.

Additional San Juan National Forest firefighters hiked into the area on Tuesday to assist with cutting fire lines and extinguishing heavy fuels. Officials also ordered a Black Hawk helicopter from the Colorado Division of Fire Prevention and Control to deliver water. The San Juan Hotshots and other national forest crews are assisting the LPFD with containment efforts.

The Hermosa Fire remains at approximately 1.5 acres.

The cause of the fire remains under investigation.