Heaviest smoke stays east of Colorado

 For the time being, Colorado is avoiding the worst of the smoke impacts coming from large wildfires in Canada. The below satellite image from Saturday afternoon shows a large whirl of smoke across the central U.S. moving to the southeast.  This has kept the heavy smoke out of Colorado for the most part, with just slightly elevated fine particulate (PM2.5) levels across the northeastern corner of the state.  Some light amounts of smoke could linger overnight and possibly be pulled into the northern Front Range region by Sunday morning.  So it's not out of the question that there could be a hazy sky overhead on Sunday for Denver, Boulder, Ft. Collins and Greeley.  However, major health impacts from smoke appear unlikely at this point.

Visible satellite image showing smoke over South Dakota, Nebraska, Kansas, and other states to the east.

Hazy skies on Friday, limited surface impacts expected

There is good news and bad news on Friday morning. The bad news is that the plume of smoke from Canadian wildfires has reached Colorado. The good news is that the vast bulk of the smoke has remained aloft, and virtually no surface impacts have been seen as of Friday morning. We expect that hazy skies will be present over the region Friday and into Saturday, but we remain optimistic that this will be the main impacts that we see.

Satellite image from CIRA shows a plume of smoke over the Colorado Front Range and eastern plains at 8:40 am (1440 UTC) on Friday, May 30, 2025.

As the large-scale atmospheric pattern shifts eastward, the likelihood of a long-lasting transport episode decreases. However within the transport that is already underway, the possibility of seeing some of this smoke reach the surface cannot be ruled out entirely. The current outlook shows increasing surface concentrations most likely on Saturday afternoon, with AQI levels remaining in the Good to Moderate range.

Hazy skies expected on Friday, possible light to moderate areas of smoke in E Colorado

Large wildfires in Canada are producing plumes of smoke that are moving into the U.S. Some of this smoke will move over Colorado on Friday. The bulk of the smoke is expected to remain aloft, however hazy skies are likely for areas east of the Continental Divide; including the Front Range and eastern plains of Colorado. 

Satellite image from CIRA shows a smoke plume at 3 pm on Thursday afternoon (21Z 5/29/25, circled in red) from Canadian wildfires over North Dakota and Montana.

Although there may be significant amounts of smoke in the atmosphere above our state, only some of this smoke has a chance to reach the surface and affect air quality. Currently, models are only showing light to moderate amounts of fine particulates near the surface, possibly arriving Friday afternoon and evening. 

Map from the HRRR-Smoke model of near-surface smoke at 6 pm on Friday, May 30th (00z 5/31/25) showing areas of light to moderate smoke in eastern Colorado.

As of this writing (Thursday afternoon) surface impacts have not been observed in monitored values in areas where smoke may have mixed downward. A good deal of uncertainty still remains with this situation, so we will continue to monitor things as they evolve, and will continue to provide updates as they develop. We are not expecting significant public health impacts from this event, however those who are highly sensitive to smoke/particulate pollution can find info and recommendations on ways to protect your health on CDPHE's Wildfire smoke and health page.

San Juan National Forest Prescribed Fire- May 27, 2025

The San Juan National Forest is planning a large broadcast burn on Tuesday, May 27 near Dolores, Colorado. Smoke may be visible in Dolores, Mancos, and on highways US-160, US-491, CO-145 and CO-184.

Although no major public health impacts are expected, people who are unusually sensitive to particle pollution may want to consider reducing prolonged or heavy exertion. You can find more information on how to protect your health on CDPHE's website.

More information on this burn is available on the Prescribed Fire Map and InciWeb.

Map of the San Juan National Forest Haycamp Mesa Prescribed Fire Area. The area highlighted in yellow denotes the location of planned ignitions on Tuesday, May 27, 2025.

Prescribed burning operations west of Colorado Springs

A prescribed burn is taking place on Friday, May 23rd near Rainbow Gulch, west of Rampart Reservoir. Smoke from this operation may be visible from areas in and near Colorado Springs. For more information, please refer to the Pikes-San Isabel National Forest X page. No public health impacts are expected, however information on smoke & your health can be found on the CPDHE information page.

Prescribed burn operations planned for Friday, May 16th in Boulder County

Arapaho and Roosevelt National Forest managers are planning burning operations in the Forsythe II Prescribed Burn area, located 7 miles southwest of Boulder and 5 miles east of Nederland on Friday, May 16th. This portion of the Forsythe II project may burn around 125 acres. Smoke from this operation may be visible from areas along the Front Range, including Boulder, Superior, Broomfield, and surrounding areas. While smoke impacts are expected to be minimal to the public, information on how to protect your health can be found on CDPHE's Wood smoke and your health webpage.