Colorado wildfires: Alexander Mountain fire evacuations lifted as officials name possible causes

The Alexander Mountain fire burning west of Loveland remains the largest active wildfire in Colorado, but firefighters have paused its growth for the time being. Larimer County officials lifted all mandatory evacuations related to the fire Wednesday.

Meanwhile, officials in Jefferson County say all residents evacuated due to the Quarry fire have returned home. The Bucktail fire burning near Nucla has seen some growth, but there are still no risks to people or buildings in the area.

Wednesday will bring Front Range temperatures into the 90s again, according to the National Weather Service. The eastern half of the state can expect scattered thunderstorms, and possibly small hail, in the afternoon and evening. Rain will be heavier on the Western Slope.

Thursday will be significantly cooler for the entire state, with the NWS expecting temperatures to drop 20 to 30 degrees in some places.

Air quality Wednesday is good overall, according to the Colorado Department of Public Health and Environment. Wildfire smoke and ozone may still cause some health issues for people with sensitivities, particularly the young and elderly.

Alexander Mountain fire

Fire crews fighting the Alexander Mountain fire have halted its growth this week while continuing to make progress on containment. The Southwest Incident Management Team has announced it will transfer command back to the U.S. Forest Service and Larimer County Sheriff’s Office on Friday.

The Larimer County Sheriff's office confirmed Wednesday that it has identified the specific location the fire started, but it is still working to identify a cause. Lightning and an abandoned campfire are the likeliest sources based on information collected so far, a spokesperson told CPR News. She could not go into further detail as the investigation is still ongoing. Information on how to submit tips to investigators is included below.

As of Wednesday, all residents with buildings damaged or destroyed by the fire should already have received a phone call notifying them. The sheriff's office said if you have not received a call, there is no known damage to buildings on your property.

"Community members may see smoke and smoldering fire activity in the burn area, but the perimeter is not expected to expand," the sheriff's office said in a statement Tuesday night.

• Crews were able to push fire containment up to 83 percent as of Wednesday morning.
• The size of the fire is estimated at about 9,668 acres or 15 square miles. Officials did not report any additional growth Tuesday.
• The fire has destroyed 26 homes and damaged four others. At least 21 outbuildings were also destroyed.
• The cause of the fire is under investigation and the U.S. Forest Service is accepting evidence and emailed tips here.
• The Forest Service is asking anyone who called the tip line prior to 3 p.m. Friday to call again. It said there was a technical problem with its voicemail system, and while it has received pictures, videos and emails, investigators want to make sure they have not missed important voicemails. The tip line number is 303-275-5266.
• Mandatory evacuation orders close to the center of the fire were downgraded to pre-evacuation warnings Wednesday.
• Residents must have credentials to access their properties. Anyone who still needs credentials can contact the Larimer County Clerk and Recorder’s Office.

Quarry fire

Officials said the Quarry fire was 100 percent contained on Wednesday afternoon. It burned nearly 580 acres. Fire officials lifted all evacuations related to the Quarry fire burning west of Littleton on Tuesday. Priorities have shifted to longer-term fire suppression now that there are no homes in immediate danger, according to the Jefferson County Sheriff's Office.

• The fire sits at about 580 acres and is 100 percent contained as of Wednesday evening. 
• A spokesperson for the sheriff's office said Wednesday that all evacuated residents have returned home. The evacuation center at Dakota Ridge High School shut down Tuesday night.
• County officials say residents who are no longer in a pre-evacuation area should make plans to pick up any large animals they dropped off at the Jefferson County Fairgrounds.
• Officials said the fire was likely human-caused and they are investigating it as arson. 

Other fires across the state:

Bucktail fire

The Bucktail fire burning near Nucla grew slightly Tuesday along its southern and eastern edges, but officials described it as "minimal" in their 2 p.m. update. Helicopters dropped water along the fire's perimeter to quell hotspots. Crews continue to work on fire lines to prevent further growth. More rain is in the forecast for the area throughout the weekend.

• The fire's size is estimated at 3,788 acres, nearly 6 square miles, the Montrose County Sheriff's office said Tuesday afternoon. The fire is 10 percent contained.
• Officials said Tuesday afternoon storms "brought increased wind and light rain to the area," but they did not have a substantial impact on fire activity.
• No buildings are in danger and no evacuations are in place.
• The U.S. Forest Service announced additional road closures Tuesday.
• The fire's cause is still unknown.

Stone Canyon fire

The Stone Canyon fire was fully contained as of Sunday evening, according to the Boulder Office of Disaster Management. The fire burned more than two square miles north of Lyons, killing one person and destroying at least five buildings. 

The fire’s cause is still under investigation. The federal Bureau of Alcohol, Tobacco, Firearms and Explosives is helping with the review.

Currant Creek fire

The Currant Creek fire burning in western Colorado near Cedaredge was fully contained Sunday.

This is a developing story and may be updated.