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GRAND COUNTY, Colo. (KDVR) – The Black Mountain Fire, which sparked on Aug. 29, has burned 418 acres in Grand County not far from the East Troublesome burn scar.

On Saturday, fire investigators revealed the fire was started on Aug. 29 by a lightning strike.

The cause of the Black Mountain Fire was discovered by using photos and video of the fire along with mapping technology to locate the tree that was struck by lightning sparking the blaze. 

The fire reached 69% containment by Wednesday night.

The National Forest Service says additional containment was added to the north side of the fire. Aerial data shows no change in the fire size.

Crews checked for heat, looked for smoke and put out hot spots on Wednesday.

Firefighters are working on a full suppression strategy, according to the incident management team.

Temperatures will be about 78 degrees over the fire area, with wind gusts up to 18 mph on Thursday. Humidity levels will drop to 9%.

The sheriff’s office said there are no evacuations at this time. Pre-evacuations in two zones in rural Grand County near Parshall remain in effect.

Credit: Medicine Bow-Routt National Forests & Thunder Basin National Grassland