Elevated levels of smoke linger in areas near prescribed burns in southwestern Colorado

PurpleAir particulate monitors show that localized areas of smoke have continued to linger during overnight and early morning hours, due to prescribed fire activity that took place this week.

Screenshot from PurpleAir showing elevated levels of smoke in localized areas near Pagosa Springs, CO on Saturday morning. Raw PM2.5 data are corrected with US EPA conversion factor, using 1 hour timeseries, valid at 8:21 am on September 20, 2025.

Over the last several days, we have seen higher particulate numbers early in the day, with concentrations decreasing during the afternoon and evening as daytime mixing of the atmosphere and smoke dispersion take place. This pattern may continue until fuels have stopped smoldering. Similar smoke behavior may also be observed in other areas where prescribed burning has recently been performed.

We urge anyone in areas that are affected by smoke, especially those who are sensitive to particulate pollution, to remain aware of conditions and protect your health through whichever actions are most appropriate for you.

Prescribed burns in southern Colorado

 A 370-acre prescribed fire is scheduled for today in San Miguel County. This burn is located northeast of Dove Creek. Smoke may be visible in the area on Friday, but no major public health impacts are expected. If you are near the burn and sensitive to smoke, it's a good idea to protect your health. 

Location of the burn in relation to Dove Creek, Colorado. Image courtesy of Google Maps.

Also, smoke is lingering near Pagosa Springs from another prescribed fire, which took place on Thursday. This smoke may continue Friday morning, but should begin to clear by the afternoon.

Purple Air sensors near Pagosa Springs show smoke is lingering Friday morning. Sensors show 1-hr Raw PM 2.5 data, current as of 11:15 AM.

Visit our Prescribed Fire Map page or the Prescribed Fire Information tab above for more information on prescribed burns.

Large prescribed burn taking place on Thursday in SW Colorado

 A 400 acre prescribed burn is planned to take place today near Pagosa Springs. The Brockover Devil Creek Rx project is located north of Highway 160, in between Pagosa Springs and Chimney Rock. Smoke may be visible in this area as these operations take place. Please see the Prescribed Fire tab above for more information.

Location of the prescribed burning operations is shown on a map, courtesy of the National Weather Service spot forecast Monitor page.

While no significant public health impacts are expected from this operation, folks in this area who are sensitive to smoke may choose to take actions to prevent health impacts.

Some smoke improvements for Sunday

In northwestern and north-central Colorado, the smoke has mostly moved out. An Air Quality Health Advisory was in effect Saturday, but will expire at 9 am today. PurpleAir sensors across the northwest have shown a dramatic reduction in Particulate Matter concentrations as of this morning. Particulate matter concentrations are expected to be in the Good to Moderate range on Sunday and Monday.

On the Front Range and eastern Plains, smoke is lingering this morning. But changes are on the way. Unsettled weather, shifting winds, and scattered showers will help to clear out the lingering smoke. Particulate Matter concentrations are expected to drop throughout the day on Sunday.

CDPHE does not anticipate issuing any Air Quality Health Advisories at this time. For the most up-to-date air quality information, visit CDPHE's Monitoring Website or PurpleAir.

Lingering smoke on Saturday

 Smoke began moving into northwest Colorado on Friday afternoon. Northwestern and north-central Colorado are waking up to smoky conditions this weekend. This smoke is expected to continue through Sunday morning. 

An Air Quality Health Advisory remains in effect for northwestern and north-central Colorado until Sunday morning. This advisory was issued on Friday afternoon for Moffat, Routt, Jackson, and Grand Counties. As of Saturday morning, this advisory has been updated to include three more counties: Clear Creek, Gilpin, and Summit. Moderate to heavy smoke is possible throughout the advisory area on Saturday and Sunday. 

Changes are coming on Sunday. Today, upper-level winds are coming from the northwest, where the smoke is heavy. On Sunday, these upper-level winds are expected to shift to westerly (coming from the west), where the air is cleaner. A shift to westerly winds would bring cleaner air into northwest Colorado. Particulate Matter concentrations are expected to drop throughout the day on Sunday. Until then, in the advisory area, it's a good idea to take steps to protect your health. For the latest air quality information, visit CDPHE's monitoring website or PurpleAir.

Smoke moving into northwest Colorado

 Smoke has been impacting eastern Colorado for most of this week. Today, smoke has begun moving into counties west of the Divide. We'll break it down, starting in the northwest corner of the state. 

Northwestern Colorado is experiencing the heaviest smoke. Purple Air sensors show that particulate matter concentrations began rising on Friday afternoon. This smoke is expected to linger Friday night into early Saturday morning. An Air Quality Health Advisory is in effect for Moffat, Routt, Jackson, and Grand Counties through Saturday morning.

Further south, in Eagle, Summit, Gilpin, and Clear Creek Counties, smoke is less intense. There will be noticeable haze along I-70 on Friday afternoon and Saturday morning.

Purple Air Sensors show that the heaviest smoke is in northwestern Colorado.

On the Front Range, the heaviest period of smoke is behind us. Particulate Matter concentrations are expected to be in the Moderate category throughout the weekend.

Air quality is expected to improve next week, as upper-level winds shift and smoke clears out.

Wildfire smoke continues to increase

Smoke has arrived to the northeastern plains of Colorado.  Moderate to heavy smoke has been observed across the northeastern corner of the state.  Fortunately, as we stated in our last post, we don't expect this smoke to be around for an extended period of time.  A cold front later on this evening should usher in some cleaner air overnight and air quality should be improved in places like Julesburg, Sterling, Ft. Morgan, and Akron by Friday morning.  In the meantime, reducing exertion is probably a good idea for the remainder of today.  This is especially true if you suffer from heart or lung ailments.

Hazy skies and poor visibility in Akron, Colorado Thursday afternoon.  Webcam image is courtesy of Viaero Wireless Weather Cameras

Meanwhile, smoke is also increasing further west along the northern Front Range urban corridor.  Fine particle concentrations are increasing in Denver, Boulder, Longmont, Ft. Collins, Greeley, and other areas along and near Interstate 25.  Combined with typical urban pollution, both ozone and fine particulate concentrations are inching towards the Unhealthy for Sensitive Groups category.  Therefore, an Action Day for Multiple Pollutants has been issued for the northern Front Range. We anticipate both ozone and fine particulates to be elevated through this evening, so avoiding prolonged or heavy exertion is recommended through late tonight. By tomorrow (Friday), ozone will likely decrease somewhat with cooler air rushing in behind the cold front.  However, fine particle concentrations could remain elevated for a longer period of time.  Health impacts from prolonged exposure to wildfire smoke can linger even after the air quality improves, so it may be a good idea to plan on reducing exertion through at least tomorrow afternoon.

Haze over the Denver skyline from the Colorado Air Pollution Control Division web camera

We are also closely monitoring other parts of Colorado for increasing wildfire smoke.  East-central and southeastern parts of the state, including Burlington, Lamar, Colorado Springs, and Pueblo could see an increase in particle pollution overnight tonight and continue into the Friday morning commute.  The same can be said for northwestern parts of the state with the possibility for a larger smoke intrusion tomorrow afternoon in places like Steamboat Springs and Granby. More information to follow as this situation continues to evolve.

Smoke arriving from out-of-state on Thursday

Smoke from fires in areas upwind from Colorado is now making its way toward, and into Colorado. Surface concentrations are currently in the Moderate category in most areas of Colorado, however the numbers have climbed in areas just to our north and east throughout the morning, and the this trend is expected to be seen in eastern Colorado as the day progresses.

Satellite image of the western United States shows a large plume of smoke across many states, reaching from the Pacific Northwest into Montana, Wyoming, and Nebraska. This smoke will make its way into Colorado on Thursday afternoon (smoke plume and likely path of travel indicated by red arrow). Image courtesy of RAMMB/CIRA.

Increases in particulate concentrations will be seen first in the far northeastern portions of the state as surface smoke moves in, and daytime mixing of the atmosphere draws smoke aloft down to ground-level. Locations such as Sterling and Fort Morgan will be the first to notice this change.

Winds out of the north-northeast will then push the smoke further to the south and west. This will likely produce hazy skies and elevated particulate concentrations in many areas of eastern Colorado, including the Front Range.

Currently we do not expect that any Air Quality Health Advisories or Action Days will be necessary. Models and observations both indicate that the smoke plume is relatively concentrated, meaning that once the densest portion of the plume moves through, concentrations are likely to decrease once again. However in the short-term, we expect particulate levels to increase on Thursday afternoon and evening before relief arrives on Friday. If conditions worsen further than we expect them to, we will be watching closely and will issue Advisories as needed.

Folks who are sensitive to smoke and particulate pollution should begin taking steps to avoid exposure and reduce potential health impacts now. Helpful tips and actions can be found on our Smoke and Health page.

Stay informed by checking in here and on CDPHE's webpage for information regarding advisories. You can also see the location of the smoke plume and surface observations at EPA's Fire and Smoke Map.

More smoke arriving later this week

 Many large wildfires are burning in the Pacific Northwest and British Columbia. Smoke from these fires could begin to impact northeastern Colorado by Thursday afternoon.

A heavy blanket of smoke is visible over western Canada and the northwestern United States. This smoke could move into Colorado by Thursday afternoon. Image courtesy of CIRA-RAMMB.

In the Pacific Northwest, particulate matter is in the Unhealthy for Sensitive Groups to Unhealthy Range today. Some smoke has made its way into Colorado, but particulate matter is in the Good to Moderate range today. Tomorrow, particulate matter could increase as the smoke to our north begins to push south.

By Thursday afternoon, the wind will begin to increase. Northerly winds will push smoke into northeastern Colorado. Smoke will hit Fort Collins, Greeley, Fort Morgan, Sterling, and Julesburg first. Then, it will continue to move south, hitting Boulder, Denver, and Colorado Springs. Particulate Matter concentrations will increase as the smoke moves in. If you are sensitive to smoke, take steps to protect your health on Thursday.

Visit the Idaho Smoke Blog or the Washington Smoke Blog for more information on smoke in the Pacific Northwest.

CDPHE is monitoring the situation and will issue an Air Quality Health Advisory if necessary.

Smoke heading towards Colorado

The fires in western Colorado have calmed down, but more smoke may be in the picture today.

Activity on the Derby Fire and Stoner Mesa Fire has slowed significantly. We do not expect heavy smoke from either of these fires today.

However, multiple fires are burning in the Pacific Northwest and Canada. This smoke may move into Colorado by Tuesday afternoon. 

On visible satellite imagery, smoke (gray) is visible over the Pacific Northwest and Canada. This smoke could move into Colorado on Tuesday afternoon.

How much smoke are we talking? In eastern Colorado, there may be a noticeable haze this afternoon. Particulate Matter is expected to reach the Moderate level in locations along the Front Range and northeastern plains, including Fort Collins, Greeley, Sterling, Julesburg, Boulder, Denver, and Colorado Springs. If you are particularly sensitive to smoke, consider taking it easy today. 

Smoke may also impact areas west of the Continental Divide. Locations in north-central Colorado, including Steamboat Springs, may see haze and increased particulate matter concentrations this afternoon.

The current weather pattern is expected to continue for the rest of this week. Continued northerly surface winds could bring more smoke into Colorado later this week. We will provide updates as necessary.

Currently, no Air Quality Health Advisories are in effect. CDPHE is monitoring the situation and will issue an advisory if conditions worsen.