Scattered showers and thunderstorms are expected across large portions of western Colorado on Sunday, possibly including the Stoner Mesa fire and the Derby fire sites. Air quality health advisories will remain in effect for areas close to those two fires and smoke levels remain elevated Sunday morning. However we are cautiously optimistic that there will be a general improvement in air quality over the next 24 hours due to less fire activity from cloud cover, and perhaps wetting rains from the shower and thunderstorm activity.
The CDPHE Air Pollution Control Division periodically updates this page to provide information about smoke in Colorado. This page covers wildfire activity, prescribed burning operations, and the transport of smoke from out-of-state sources.
Si desea solicitar interpretación al español, envíe un mensaje por correo electrónico a cdphe_apcd_outreach@state.co.us
Accessibility statement and support
Sunday, August 24, 2025
Increasing wet weather
Saturday, August 23, 2025
No major changes for the time being
Air quality conditions Saturday morning look very similar to what they were 24 hours ago (see yesterday's blog post below). Heavy smoke is mainly found in close vicinity to the Stoner Mesa fire in southwestern Colorado and the Derby fire in central Colorado. Air quality health advisories will continue for these areas through at least Sunday morning.
There will be a scattering of showers and thunderstorms near the two fires Saturday afternoon, but wetting rains appear more likely on Sunday. We are hopeful this will continue the gradual improvement in air quality as we head into the early part of the workweek.
Friday, August 22, 2025
Relief on the way?
Another day of localized heavy smoke near the Stoner Mesa fire and the Derby fire. Much like yesterday, the heaviest smoke will likely remain in close vicinity to the fires. For Stoner Mesa, parts of western Eagle and eastern Garfield Counties remain in the advisory area. The Sweetwater Lake area along with Colorado River Road between Dotsero and Burns will receive heavy smoke during the overnight and early mornings, with improving air quality during the afternoons. Yesterday afternoon we did see some downwind impacts in places like Basalt and Aspen. That possibility exists again today, but with showers and thunderstorms possible near the fire there could be gusty, erratic winds that could send smoke in any direction. Regardless, we don't anticipate smoke to travel very far from the fire site today.
At the Stoner Mesa fire, there has been very heavy smoke along Highway 145 between Dolores and Rico. The Stoner area has been especially hard hit, so if you are camping or reside in this area please take action to protect your health. You can even create a clean air space in your RV by constructing a DIY air cleaner.
The forecast appears encouraging for western Colorado over the next few days as a surge of monsoonal moisture should help decrease fire activity and smoke production. In the meantime, we'll continue to monitor the smoke and issue advisories if necessary.
Thursday, August 21, 2025
Smoky conditions will continue Thursday for parts of central and southwestern Colorado
The Derby fire is located in central Colorado approximately 13 miles north of Dotsero and remains quite active Thursday morning. CDPHE issued an air quality health advisory yesterday for four counties due to smoke moving to the south and east of the fire. One concern was that smoke would be trapped within the narrow mountain valleys in this area, but fortunately many parts of the advisory area only have light to moderate smoke Thursday morning. Therefore, the advisory for today will be smaller with the removal of Summit, Lake, and Pitkin Counties. Eastern parts of Eagle County also look OK, but the advisory today will continue for western Eagle County with the addition of a small part of eastern Garfield County. Below is a map with areas most likely to receive periods of heavy smoke through Friday morning.
Heavy morning smoke can be expected in the vicinity of Sweetwater Lake in eastern Garfield County, along with locations on Colorado River Road between Dotsero and Burns. Meanwhile, the stretch of Interstate 70 between Dotsero and Eagle (including Gypsum) are also included in today's advisory.
A new data point has revealed that heavy smoke is still impacting parts of southeastern Dolores and northeastern Montezuma Counties in southwestern Colorado from the Stoner Mesa fire. Campgrounds and residences along Highway 145 between Dolores and Rico, especially in the Stoner area, will experience heavy smoke Thursday morning with likely some improvement during the afternoon hours. Smoke will likely return again to this area late Thursday night and early Friday morning.
Looking ahead, there is some promising news in the long-range forecast for the Western Slope. An increase in monsoonal moisture is anticipated starting on Friday and continuing into the weekend. This should help to decrease fire activity and smoke production somewhat, but we will also need to monitor for potential new fire starts from lightning strikes.
Wednesday, August 20, 2025
Air Quality Advisory issued downwind of the Derby wildfire
The Derby fire has grown significantly over the past 24 hours and is producing very large amounts of smoke Wednesday afternoon. The transport winds over the fire are not particularly strong, but they are pushing smoke to the south and east. This has resulted in increased fine particulate (PM2.5) concentrations and worsening air quality across large swaths of Eagle, Summit, Pitkin, and Lake Counties. An Air Quality Health Advisory for Wildfire Smoke has been issued for this area through at least 9am Thursday morning.
The numerous communities along that long stretch of Interstate 70 between Silverthorne and Dotsero will be impacted by reduced visibility and periods of moderate to heavy smoke. Also expect increasing smoke Wednesday evening in places like Aspen and Leadville. So please drive safely in areas where visibility is obscured. And as always, we remind you to please take action to protect your health. The valleys in this part of Colorado are notorious for trapping smoke, so this could very well be an issue through the Thursday morning commute.
Derby Fire burning in Eagle County
A new fire has sparked in northern Eagle County- the Derby Fire.
Smoke from this fire is visible on satellite and is spreading south and east. Smoke may be visible Wednesday morning along the I-70 corridor, including Dotsero, Gypsum, Eagle, and Edwards. Throughout the day, there may be brief periods of moderate smoke. Particulate matter concentrations may begin to increase Wednesday afternoon, but will likely remain in the Moderate category.
No major public health impacts are expected at this time, and there is no Air Quality Health Advisory in effect. CDPHE is monitoring the situation and will issue an advisory if conditions change. Find the latest air quality information on PurpleAir or on CDPHE's monitoring website.
Sunday, August 17, 2025
Areas of morning smoke near the fires on Sunday
Air quality monitoring and satellite imagery reveal some smoke located in close vicinity to West Slope wildfires Sunday morning. Smoke has drained overnight from the Stoner Mesa fire extending southwestward into Montezuma County with smoke being reported in Dolores, Cortez and Towaoc. Fortunately, this smoke should decrease as progress through the morning and no advisory is necessary at this time. If you do want to spend time outdoors in this part of Colorado, waiting until this afternoon would probably be the best choice for your personal health. The same holds true for those located close to the Crosho fire or Lee fire located in Rio Blanco County in northwestern Colorado.
The weather is steadily drying out across western Colorado so the wildfires may start getting active again Sunday afternoon. We will keep you posted if any air quality advisories are necessary.
Saturday, August 16, 2025
Air quality improves for Saturday
Today is the day- finally, no air quality health advisories are in effect!
The Lee Fire, Crosho Fire, and Stoner Mesa Fire are still burning. On Friday, western Colorado experienced rain and high relative humidity. This limited the fires' growth and resulted in less smoke from these fires. Today, Coloradans are waking up to cleaner air.
We do not expect Particulate Matter concentrations to reach the Unhealthy for Sensitive Groups (orange) category today. There still may be a noticeable haze today. In areas near the fires, there may be periods of moderate smoke. If you are very sensitive to smoke, you can take steps to protect your health. But know that today will be an improvement from earlier this week.
Particulate matter concentrations are in the Good to Moderate range statewide.
CDPHE is still monitoring these fires and will issue advisories as needed.
Friday, August 15, 2025
Significant improvement in air quality for many areas
Widespread cloud cover, higher relative humidity, and even a few showers and thunderstorms resulted in a decrease in fire activity yesterday on the Western Slope. The result is lower smoke levels for most of Colorado Friday morning. More good news -- moisture continues to surge into western Colorado. This should moderate fire activity again for today and limit smoke production.
Thursday, August 14, 2025
Wildfire smoke remains in the forecast for many
Most of Colorado is experiencing at least moderate levels of smoke Thursday morning. The heaviest smoke can be found in close vicinity to wildfires in western parts of the state, while the Colorado River Valley between Gypsum and Vail is also seeing highly elevated levels of fine particulate matter.
Unfortunately Red Flag Warnings blanket the western half of Colorado on Thursday. The primary threat will be dry thunderstorms which could initiate new fires and perhaps enhance current fires due to gusty winds. CDPHE meteorologists will be closely monitoring for new wildfire starts throughout the day.
Wednesday, August 13, 2025
Increased fire activity and smoke possible today for parts of Colorado
Unfortunately, it appears that the hot, dry, and increasingly windy weather could increase fire activity on Wednesday. The biggest area of concern will be the large wildfires burning in Rio Blanco County. These include the Lee fire and the Crosho fire. A Red Flag Warning has been issued by the National Weather Service for this area, which could lead to explosive wildfire growth and enormous amounts of smoke. We will be closely watching areas downwind (to the east) of these fires where smoke could quickly increase Wednesday afternoon and evening. Several counties to the east of the fires have been added to the air quality health advisory currently in effect for this area. Heads up today along Interstate 70 in Vail and Breckenridge, along with areas to the north including Kremmling, Fraser, and Granby.
Further south, areas of heavy smoke have been observed Wednesday morning in and around Grand Junction, Montrose, Delta, and Gunnison. Although we are expecting gradually improving air quality conditions in this area Wednesday afternoon, the Turner Gulch fire in Mesa County is still producing smoke. Therefore, this area will remain within the air quality health advisory for the time being.
Even further south in southwestern Colorado, the Stoner Mesa fire remains active. The weather conditions at this fire on Wednesday will not be quite as dry or windy as the fires to the north, which is good news. However, heavy smoke will continue to be an issue for areas in close vicinity to the fire such as the communities of Rico and Dolores. Some downwind impacts will also remain possible Wednesday afternoon and evening in Telluride, Silverton, Ouray, and Lake City, with the air quality health advisory remaining in effect for this area through at least Thursday morning.
Tuesday, August 12, 2025
Smoke impacts continue on Tuesday, expected to be more localized
Several wildfires will continue to produce smoke on Tuesday, affecting air quality conditions for many areas of western Colorado. Wildfires in Rio Blanco and Mesa Counties will create impacts in northwestern and central Colorado, and fires in Dolores and Archuleta Counties will influence areas in southwestern portions of the state. The main difference in our expectations for today (versus yesterday) is that transport winds look to be lighter and less organized. This means that a lot of the smoke that is produced will remain in areas close to the fires. Air Quality Health Advisories for Wildfire Smoke will remain in place into Wednesday morning covering several counties, however please note that the footprint has changed somewhat.
Map of Colorado showing counties that are under advisories for smoke on Tuesday and Wednesday (shaded in grey). Map from colorado.gov/airquality .
One notable difference on Tuesday is the presence of smoke in the Grand Valley, including Grand Junction. The amount of smoke seen in this area has prompted the addition of Mesa County to the advisory area covered by the Lee fire and the Turner Gulch fire. Although smoke will remain within the valley through the morning hours, a gradual decrease has already been seen on Tuesday morning. This trend is expected to continue as atmospheric mixing increases. Improvement of conditions is expected in Grand Junction throughout the day on Tuesday.
A similar story is expected to unfold in southwestern Colorado near the Stoner Mesa fire in Dolores County. Smoke impacts will remain more localized than on Monday, with surface concentrations decreasing throughout the day in many areas. Drainage winds will still draw smoke toward lower terrain overnight, affecting eastern Dolores and northern Montezuma Counties.
We continue to watch all active incidents and will continue with updates here as things develop.
Monday, August 11, 2025
Smoke in many areas of western Colorado, with varying impacts and expectations
Wildfires and smoke will continue to be a part of many peoples' lives and conversations as we start the week, and rightfully so. There is much to address, so we will work from north to south, attempting to cover all aspects.
The largest fire(s) in Colorado, producing some of the greatest impacts include the Lee and Elk fires in Rio Blanco County. Combined, these fires cover around 130,000 acres and have limited containment as of Monday. Winds will transport smoke to areas to the south and southeast of these fires, creating smoke impacts in neighboring counties. Information on the extent of the greatest impacts can be found in the Air Quality Health Advisory for these fires.
Satellite image of heat detection of wildfires showing the location of fires throughout western Colorado. Image courtesy CIRA/CSU.The second area of fire activity is in relation to the Turner Gulch fire in southern Mesa County. This fire continues to be active in interior portions of the fires' footprint, yet has not shown widespread smoke impacts for several days. Areas in the immediate vicinity of the fire will continue to see some smoke, and some areas may have moderate to heavy impacts at times. However from the information that is available to us including monitoring and coordination with fire managers, the severity and period of impacts from smoke do not support an Air quality Health Advisory for this fire at this time.
The third fire that is causing air quality impacts is the Stoner Mesa fire in eastern Dolores County. Smoke from this fire has largely been localized to areas near the fire, however as fire intensity and smoke production grows on Monday, additional areas may see smoke from this fire. Areas such as Cortez and Durango have seen intermittent periods of moderate to heavy smoke, however similar to the Turner Gulch fire, the duration and severity of these episodes have not justified inclusion in advisories so far. As of this writing (Monday) the Air Quality Health Advisory for Wildfire Smoke related to this fire only coverers eastern Dolores County; though this may change with updated information.
The heat from all of these fires can be seen in the satellite image above, which shows infrared energy emitting from these incidents. What is not seen in the satellite image (or is very hard to discern) is the locations of two fires that are affecting areas of Archuleta County.
The Middle Mesa fire is in New Mexico, just south of the Colorado border, and the Oak fire is in Archuleta County to the northwest of Pagosa Springs. Both of these fires are certainly contributing to the presence of smoke in this region. However, as with other areas already motioned, the severity of impacts have not yet risen to levels that trigger an advisory.
CDPHE issues advisories when the AQI for particulate matter is expected to reach the Unhealthy for Sensitive Groups level over a 24 hour period. We are monitoring conditions and will issue more advisories as needed.
With all of this said, keeping the public informed of our expectations, and providing information so that you can make decisions on how best to protect your health is our ultimate goal. We will continue to monitor all of these situations as they evolve, and post additional updates as information becomes available.
Sunday, August 10, 2025
Sunday smoke update
The Lee Fire and Elk Fire are still burning in Rio Blanco County. An Air Quality Health Advisory remains in effect for a large area of central Colorado.
The Stoner Mesa Fire is still burning in Dolores County. An Air Quality Health Advisory is also in effect for eastern Dolores County today.
The advisory areas have slightly changed today. In central Colorado, Grand County has been added to the advisory area. In southwest Colorado, the advisory area only includes eastern Dolores County. Periods of moderate to heavy smoke are possible throughout both advisory areas on Sunday and Monday.
If you are sensitive to wildfire smoke, it's a good idea to take steps to protect your health today.
Saturday, August 9, 2025
Smoke further south on Saturday
It may be the weekend, but smoke isn't taking a day off.
The Lee Fire and Elk Fire continue to burn in Rio Blanco County. Smoke from these fires has moved south today, and Particulate Matter concentrations in central Colorado are higher. Cities and towns along the I-70 corridor, including Rifle, Eagle, and Vail, woke up to hazy, smoky skies this morning. Smoke is expected to stay south of Rio Blanco County today. In central Colorado, an Air Quality Health Advisory is in effect until 9 am Sunday morning.
The Stoner Mesa Fire in Dolores County is also still burning today. Smoke from this fire has moved further east today, and a larger area is under the Air Quality Health Advisory.
If you are in a location under a Health Advisory, it's a good idea to take steps to protect your health today. Stay up-to-date with the latest air quality conditions on CDPHE's monitor map or Purple Air.
Also, a Red Flag Warning remains in effect for a large area of western Colorado, Utah, and Wyoming. CDPHE is monitoring the situation and will provide updates as needed.
Friday, August 8, 2025
Smoke continues in Colorado
Smoke is expected to continue today. Air Quality Health Advisories remain in effect for many counties in Colorado.
In northwestern Colorado, large wildfires are burning in Moffat and Rio Blanco Counties. Smoke from the Twelve Fire, Lee Fire, and Elk Fire is impacting much of northern Colorado.
In Dolores County, the Stoner Mesa Fire continues to burn. An Air Quality Health Advisory remains in effect for western Dolores County.
If you are sensitive to wildfire smoke, it is a good idea to take steps to protect your health. Visit CDPHE's monitoring website or Purple Air for real-time air quality data near you.
Additionally, a Red Flag Warning is in effect for several counties in western Colorado, Wyoming, and Utah. Any fires that spark could grow quickly today. We are monitoring the situation and will provide an update if necessary.
Ready for some good news? On the Front Range, air quality has improved from yesterday. On Thursday, there was an Action Day for Multiple Pollutants. Ozone and Particulate matter have improved slightly, and Good to Moderate air quality is expected for the Northern Front Range today.
Thursday, August 7, 2025
Thursday smoke update
Smoke will continue for much of Colorado today.
In Moffat and Rio Blanco Counties, the Twelve Fire, Lee Fire, and Elk Fire are burning.
Smoke from these fires has moved east and is impacting a large area of northern Colorado. An Air Quality Health Advisory is in effect for northern Colorado. As of this morning, four counties were removed from the advisory area (Garfield, Eagle, Gilpin, and Clear Creek.) Smoke will remain further north today.
On the Front Range, an Action Day for Multiple Pollutants is in effect. Both Particulate Matter (from smoke) and ozone are expected to be high today in Fort Collins, Greeley, Boulder, and the Denver Metro area.
In Dolores County, the Stoner Mesa Fire is still burning. An Air Quality Health Advisory is in effect for eastern Dolores County today.
Additionally, a Red Flag Warning is in effect for several counties in western Colorado, Wyoming, and Utah. Any fires that spark could grow quickly today. We are monitoring the situation, and will provide an update if necessary.
If you are sensitive to wildfire smoke, it is a good idea to take steps to protect your health. Visit CDPHE's monitoring website or Purple Air for real-time air quality data near you.
Wednesday, August 6, 2025
Smoke further east on Wednesday
On Wednesday, more Coloradans will be breathing in smoke. Let's break it down from north to south.
The Lee Fire and the Elk Fire are burning in Rio Blanco County. Smoke from these fires has moved east, reaching as far as the Northern Front Range. Moderate to heavy smoke is expected from Rio Blanco County and eastward to Weld County. An Air Quality Health Advisory is in effect.
Tuesday, August 5, 2025
Continued smoke on tap for Tuesday
The smoke continues today in western Colorado. Air Quailty Health Advisories are in effect for several counties on the Western Slope. We'll discuss the details in two parts.
First, fires burning in Rio Blanco and Garfield Counties are causing air quality impacts for a large portion of western Colorado. The heaviest impacts will be in locations near the Grease/ Lee Fires, Elk Fire, and Coulter Creek Fire.
Smoke is expected to move further east today, so this advisory was updated to include Grand and Jackson Counties.
Monday, August 4, 2025
Wildfires in western Colorado could intensify today
Smoke from several wildfires is impacting western Colorado today.
The Grease Fire, Lee Fire, Elk Fire, and Coulter Creek Fire are burning in northwest Colorado. An Air Quality Health Advisory for Wildfire Smoke is in effect until 9 am Tuesday for eastern parts of Rio Blanco and Garfield Counties, along with the entirety of Routt and Eagle Counties. Areas close to the fires will obviously see periods of moderate to heavy smoke today, including the Meeker area.
Additionally, dry and windy weather is on tap for today. A Red Flag Warning is in effect for a large portion of western Colorado, as well as parts of Wyoming and Utah. This means that any new or existing fires could grow quickly today and produce large amounts of smoke. We will be closely watching areas well downwind of the fires today, including Steamboat Springs which could see an increase in smoke later this afternoon and into this evening.
If you are particularly sensitive to smoke, it's a good idea to take steps to protect your health.
Sunday, August 3, 2025
New fires spark in western Colorado, fires in other states still active
Several wildfires are creating air quality concerns in areas of western Colorado. The Grease fire and the Elk fire are located in central and eastern Rio Blanco County, and the Coulter Creek fire is located in southeastern Garfield County. These fires will produce areas of moderate to heavy smoke on Sunday evening and Monday morning, particularly in areas of low lying terrain in the immediate vicinity of the fires.
An Air Quality Health Advisory for Wildfire Smoke has been issued for areas near these fires through at least Monday morning. Folks in these areas should take steps to avoid exposure to smoke and limit health impacts.
Fires in other states continue to produce smoke, resulting in light to moderate concentrations of fine particulates in other areas of the State. While conditions across the western slope and 4-Corners regions of Colorado do not warrant advisories at this time, anyone in these areas should also remain aware of air quality conditions due to the presence of smoke.
We will continue to provide updated information on smoke impacts, including additional advisories if necessary.
Friday, August 1, 2025
Wildfires still burning, moderate smoke impacts expected through the weekend
Many areas of Colorado have noticed the presence of wildfire smoke this week, with hazy skies and Moderate particulate concentrations. Unfortunately, this is expected to continue through the coming weekend. Fire activity in Colorado has remained moderate, with the primary influence being from the Turner Gulch Fire in southern Mesa County. However the Monroe Canyon fire in central Utah and the Dragon Bravo fire in Arizona have continued to display active fire behavior, and are expected to remain this way during the coming weekend.
Map from fire.airnow.gov shows the location of several fires in the western U.S., with smoke plumes extending over Colorado. Air quality monitors show Moderate (yellow) smoke impacts.
Upper level transport winds are expected to shift, becoming more west-to-east in orientation throughout the weekend. This will bring smoke from fires more directly into Colorado, likely continuing the Moderate impacts that have been seen this week.
Resulting impacts will depend on just how active the fires are, the direction and altitude of smoke transport, and how deep atmospheric mixing is in areas where the plumes traverse. As always we will keep a close watch on air quality conditions and will send messaging and alerts (if needed) to keep you informed. We also encourage folks to take note of conditions in your location, and take the steps most appropriate for your situation to minimize effects of smoke exposure.
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