Goltra Fire burning in Jefferson County

The Goltra Fire is burning in Jefferson County approximately 1 mile west of Golden. The fire is estimated at 200 acres as of Wednesday morning. 

Purple Air sensors downwind of the fire show elevated particulate concentrations this morning. Light smoke and hazy skies are possible in Golden and north Denver throughout Wednesday. Visit CDPHE's website for information on how to protect your health during periods of wildfire smoke. 

Rain and high relative humidity are expected Wednesday which could aid firefighting efforts, and limit air quality impacts.

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

EPA's Fire and Smoke Map shows the location of the Goltra Fire, with elevated particulate matter concentrations downwind of the fire.

Where's the smoke?

After a very smoky July, August has been relatively clear. There are two reasons for the clear skies and clean air this week.

First, the local fires are under control- the Alexander Mountain and Bucktail Fires are fully contained.

Second, upper-level winds are steering smoke east of Colorado. A ridge of high pressure is situated over the western United States, so when smoke from the large wildfires in Oregon, Washington, Idaho, Montana, and Canada lofts into the atmosphere, it rides the ridge up and around Colorado, and into the Midwest. While our neighbors to the north and east are experiencing smoke, Colorado can finally breathe a sigh of relief.

Of course, the situation can change quickly if new fires spark. Stay tuned for updates.

An upper-level ridge is situated over Colorado. Image courtesy of NOAA's Storm Prediction Center.

EPA's Fire and Smoke Map shows smoke over much of the Midwest, but Colorado is in the clear.

Potential Smoke Arriving Thursday and Friday

While fire activity has died down in Colorado, smoke still lingers upwind. Several fires are burning in the Pacific Northwest, California, and Canada, and heavy smoke lingers throughout the region. 

EPA's Fire and Smoke Map shows heavy smoke over the Pacific Northwest and Canada.

Smoke may move into Northeastern Colorado beginning Thursday afternoon. Residents in Logan, Phillips, Sedgwick, and northern Weld Counties may notice hazy skies and a minimal uptick in Particulate Matter. Throughout the day on Thursday, smoke may push further south, advancing into Morgan, Washington, and Yuma Counties. 

Overnight Thursday into Friday, more widespread smoke is possible. The HRRR-Smoke model shows light smoke spanning from Fort Collins to Colorado Springs by Friday morning. There may be a noticeable haze on Friday, but no major public health impacts are expected for the Front Range. Additionally, northeast Colorado could continue to see smoke on Friday, with smoke potentially reaching as far south as the I-70 corridor.

The HRRR smoke model  shows smoke potentially moving into northeast Colorado on Thursday afternoon.

By Thursday evening,  the HRRR-Smoke modelshows smoke lingering in Northeast Colorado.

Friday morning, the HRRR-Smoke model shows smoke along the Front Range and northeastern Colorado.

Out--of-state wildfire smoke possible on Thursday for northeastern Colorado

 There's still plenty of wildfire activity across the northwestern United States, but thankfully the smoke from those fires has largely avoided Colorado for the past several days.  That might be about to change.  Although we are not anticipating heavy smoke at this time, there is certainly the possibility that particle pollution could be elevated on Thursday across the northeastern corner of Colorado, including Julesburg, Ft. Morgan, and Akron.  By Thursday afternoon and evening, some of that smoke may reach the northern Front Range region of Denver, Boulder and Ft. Collins.  Stay tuned.

EPA's Fire and Smoke Map shows numerous wildfires and heavy smoke across the Pacific Northwest on Wednesday morning, 8/14/24

Smoke may be around this weekend, but limited amounts are expected near the surface, 8/9/24

There is a bit of  'a tale of two levels (of the atmosphere)' to be told for the upcoming weekend. Fires in California and the Pacific Northwest continue to be active and produce plenty of smoke, which is likely to be transported eastward. However, much of that smoke is expected to remain aloft, in upper portions of the atmosphere, and is also expected to mostly stay to the northern areas of the western U.S., resulting in minimal surface impacts in Colorado. the images below, from the HRRR-Smoke model show the large plumes of smoke coming from the states to our west and northwest, and also show the great differences in the amounts of smoke that are expected to be found throughout the atmosphere (top) vs amounts expected near the surface (bottom).

HRRR-Smoke vertically integrated smoke at 00Z, Sunday, August 10, 2024 (6pm MDT, Saturday).

HRRR-Smoke near-surface smoke at 00Z, Sunday, August 10, 2024 (6pm MDT, Saturday).

The Big Gulch fire in Moffat County and the Bucktail fire in Montrose County continue to only report limited containment and increases in size. However, only limited and transient heat signatures have been seen on satellite (and these may have come from burning operations conducted by fire crews in efforts to strengthen fire lines) and PM2.5 monitors in these areas continue to show only light to moderate concentrations of smoke. Due to these observations, no advisories are currently in effect for these fires.

In all, only light to moderate amounts of smoke are expected for the weekend, however with ever-evolving situations such as those involving wildfires, conditions may change quickly. Pockets of smoke may be present in areas in the immediate vicinity of wildfires in Colorado, and we recommend undertaking health precautions if smoke is present in your location.

Light to Moderate smoke possible in areas of northwestern Colorado on Thursday, 8/8/24

We are glad to be reporting about the air quality impacts due to smoke in Colorado with a far lower sense of alarm than has been seen recently! However we always want to keep everyone alert to all situations that may influence public health, so we continue to monitor fires in Colorado, and those in up-wind states that may produce smoke impacts here.

The Bucktail Fire in Montrose County has remained fairly quiet, not showing significant heat or smoke production, and has allowed advisories and commentary to be unnecessary. We continue to monitor conditions in the area, although information on this fire remains sparse. We will provide updates as needed if things change in this area.

The Big Gulch fire in Moffat County (~15 miles west of Craig) increased in reported size between Wednesday and Thursday, yet this incident also has not shown significant heat or air quality impacts on Thursday. Most of the smoke seen in NW Colorado likely originated from fires that are out-of-state and is being transported into Colorado, however light concentrations of smoke emanating from the Big Gulch fire may be contributing to the yellow color of monitors shown on the fire and smoke map from airnow.gov. This indicates Moderate air quality due to fine particulates in northwestern Colorado.

Fire and smoke map showing conditions in Colorado and upwind states on Thursday afternoon.

Models also suggest that some of the smoke seen in areas of Idaho, Utah, Nevada, Oregon, and California may move into Colorado over the next couple of days, however we expect that surface impacts will remain light to moderate. There is some possibility that larger concentrations of smoke may head our way during the coming weekend, but it is a bit too early to put too much confidence in the numbers and locations that may see this influence, so we will continue to watch closely and update information on this page as expectations become more clear.

More Smoke Coming for Colorado

Northwestern Colorado could experience another shot of smoke starting tonight.

Smoke models show smoke advancing into northwestern counties as early as Wednesday night, and continuing throughout the day Thursday. Smoke from fires in Canada and the Pacific Northwest could advance into northwestern Colorado, as a cold front moves in from the north. 

Residents in Moffat, Routt, Jackson, and Rio Blanco Counties may wake up to hazy skies and noticeable smoke on Thursday morning. Smoke is expected to stick around throughout the day Thursday, so you may consider reducing your time outdoors if you are in these locations.

This model also shows light smoke moving through eastern Colorado, but widespread rain and thunderstorms are expected on Thursday, which should limit smoke impacts.

The HRRR-Smoke model at Midnight Wednesday night shows smoke beginning to advance into northwestern Colorado.

The HRRR-Smoke model shows more widespread smoke by 6 am Thursday.

Bucktail Fire Smoke Subsiding

Finally, some good news for Colorado's air!  

The Air Quality Health Advisory for Wildfire Smoke in Montrose County has been allowed to expire Tuesday morning.

Activity on the Bucktail Fire has calmed down, and satellite imagery shows an improvement in smoke this morning. Tuesday afternoon, rain is expected, which could help to limit the fire's growth. There is, however, some uncertainty in how much wind will enhance fire growth this afternoon. As thunderstorms roll through, wetting rain will help to limit fire activity, but gusty winds can contribute to growth.

CDPHE is monitoring this fire and will re-issue an Air Quality Health Advisory if necessary.

Satellite imagery shows no smoke near the Bucktail Fire as of Tuesday morning.

EPA's Fire and Smoke Map shows that all monitors near the Bucktail Fire (outlined in red) are reporting Good air quality as of Tuesday morning.

CDPHE Wildfire Smoke Preparedness Program

CDPHE's Wildfire Smoke Preparedness Program provides outreach, education, and training for local community partners on responding to wildfire smoke and its impacts on community health. For more information or if you are interested in joining our Stakeholder Education and Training Network to receive program updates and information on wildfire preparedness, please visit the Wildfire Smoke Preparedness Program webpage.

Heavy morning smoke in parts of western Montrose County

 The Bucktail Wildfire remains active in western Montrose County with morning satellite imagery  revealing heavy smoke in areas near the fire.  The communities of Nucla and Naturita are most likely to be impacted.  The good news is that we should see gradual improvement through the morning hours and into Monday afternoon as smoke begins to lift from the surface with the heating of the day.  Wet weather this afternoon may also provide benefits, but there is always that threat for gusty winds and lightning strikes which could complicate matters.  So we do ask those residents in the immediate area to remain alert to changing conditions and continue to take steps to protect your health from wildfire smoke.

Meanwhile, we continue to see nice improvement in other parts of Colorado.  The large northern Front Range wildfires have eased up quite a bit and are producing far less smoke than they were a few days ago. There are some indications that we may get a moderate smoke intrusion to the northeastern corner of Colorado later this afternoon and into Monday evening, perhaps bringing some elevated fine particulate concentrations to Sterling, Julesburg and Holyoke.  But that remains uncertain at this point and we will continue to monitor the situation throughout the day. 

Smoke conditions in many areas much improved on Sunday morning, 8/4/24

 Although the Alexander Mountain fire, Stone Canyon fire, and Quarry fire are not considered 'out', containment has increased on all of these incidents, and fire activity and smoke production has decreased significantly. Most importantly for public health impacts, only light to moderate concentrations of smoke were observed all day on Saturday, and again on Sunday morning. For these reasons, the Air Quality Health Advisory for Multiple Pollutants has been allowed to expire at 9 am on Sunday morning.

Significant improvement is seen on the fire and smoke map from fire.airnow.gov on Sunday morning, 8/4/24.

Hot and sunny weather is again expected on Sunday, and there is potential for afternoon thunderstorms to move through the fire areas. These conditions create potential for fire activity to increase and elevate concerns for smoke impacts, so we will continue to monitor all fires closely, and will re-issue any air quality alerts if they become necessary. Highly localized areas of smoke remain possible for locations in close proximity to fires, so we encourage everyone to remain aware of changing conditions and take precautions if smoke is encountered in your location, however widespread public heath impacts from smoke are not anticipated at this time along the Front Range.

The Bucktail fire in Montrose County continued to show heat and smoke throughout the day on Saturday, so the Air Quality Health Advisory for Wildfire Smoke will remain in effect for this area until at least 9 am Monday morning.

Smoke impacts on Saturday, 8/3/24

Smoke from all wildfires in Colorado showed significantly lower impacts on Saturday morning, however this does not meant that concerns for this potential have been eliminated.

Along the northern Colorado Front Range PM2.5 monitors showed mainly Green and yellow (Good and Moderate) levels of fine particulates (smoke) on EPA's fire and smoke map. This is welcome news after several days of more significant smoke throughout the region. 

Map of air quality sensors from EPA shows good to moderate air quality from Fort Collins to Castle Rock on Saturday morning.

However, hot, dry, and breezy conditions are in store once again on Saturday. This may lead to an increase in fire behavior and smoke production. Winds during daytime hours are expected to move from the east to the west, and may transport much of the smoke from the Alexander Mountain Fire and the Stone Canyon fire westward and away from population centers, however impacts will remain in areas that are in close proximity, downwind of the fires. During overnight and early morning hours, areas that are below these fires' locations may see the greatest impacts as smoke drains toward lower terrain.

Folks along the Front Range, and especially in areas near active fires should remain aware of air quality conditions, and remain vigilant about taking health precautions to reduce negative effects due to air quality.

In southwestern Colorado, the Bucktail fire remains active, and smoke is expected to again affect areas of Montrose County on Saturday and Sunday.

Information about all Air Quality Advisories and Action Days can be found on the CDPHE/APCD website, and will be updated as these situations evolve.

Continued Smoke on Friday

While there have been some reductions in smoke over the last 24 hours, Colorado is not completely in the clear just yet. Smoke from several wildfires burning in the state will continue to impact air quality on Friday.

First off, smoke from the the Stone Canyon Fire and Alexander Mountain Fire will continue to impact the Northern Front Range Region. Locations nearby and downwind of the fires will see the heaviest smoke today. The good news is, the Quarry Fire is putting out less smoke this morning, and particulate concentrations have decreased in the southwest Denver Metro.

Zooming out to the rest of the Front Range, there have been some improvements since yesterday at this time. Moderate smoke still remains throughout the northern Front Range Region, and is expected to remain moderate for the rest of today. However, thunderstorms are expected to develop Friday afternoon, which brings some uncertainty into the equation. On one hand, gusty winds help to scour out some smoke, but on the other, wind can contribute to fire growth and smoke production.

EPA's Fire and Smoke Map shows widespread smoke over the Northern Front Range Region, with localized heavy smoke in locations near the Alexander Mountain Fire.

Next, smoke from the fires burning on the Front Range has moved west into north-central Colorado. Light smoke is present this morning, including Steamboat Springs and Walden. Smoke is expected to dissipate this afternoon as daytime atmospheric mixing picks up, but could increase again this evening, depending on the fire behavior today. For those unusually sensitive to smoke, you may consider reducing your time outdoors today.

Finally, the Bucktail Fire is burning in Montrose County, approximately 5 miles northeast of Nucla. An Air Quality Health Advisory for Wildfire Smoke is in effect for Montrose County, and has been extended until 9 am Saturday. CDPHE is monitoring this fire and will provide updates as necessary.

Plume from the Bucktail Fire on Thursday afternoon. Image Courtesy of San Miguel Sheriff's office.

Late night smoke for Steamboat Springs?

 Widespread wildfire smoke continues to plague the northern Front Range region Thursday afternoon, and likely will be sticking around into Friday as well with the Action Day for Multiple Pollutants set to be extended through at least 4pm Friday.  Residents along the I-25 urban corridor, including Denver, Boulder, Ft. Collins and Greeley, should continue to take those extra steps to protect your health from wildfire smoke by limiting time outdoors, if possible, and while outside taking some extra breaks.  But the pollution is certainly not uniform across the area.  Locations in closer vicinity to the wildfires are seeing much higher particle pollution levels, and hence are receiving more concerning public health impacts.  As of 2:00pm Thursday afternoon (see image below), the heaviest smoke is located in Longmont, Niwot, Boulder and into northwestern parts of the Denver metro area.  These areas will likely continue to be impacted Thursday night and Friday morning, with a distinct possibility that the smoke could locally get even heavier (especially in Longmont) as smoke drains down from the Stone Canyon Fire. Also, please don't let your guard down in Loveland and southwestern parts of the Denver metro area.  Although air quality has improved marginally today as atmospheric mixing increased, smoke could increase again later on tonight as smoke drains from the Alexander Mountain and Quarry wildfires, respectively. 

What about the rest of Colorado?  For the most part, it's not too bad out there Thursday with generally light to moderate levels of particle pollution from some remnant light smoke.  However, there have been some indications with smoke modeling that a plume of smoke from the Front Range fires may get up and over the Continental Divide and settle into north-central Colorado overnight.

HRRR-smoke model for total column smoke at 11pm Thursday evening

Is this really going to happen?  Hard to say, unfortunately.  Although it looks fairly likely that smoke currently up in the atmosphere over the Front Range fires will push to the northwest towards north-central Colorado overnight, there is less confidence that smoke will be able to mix down to the earth's surface and create public health issues. 

Regardless, it's probably not a bad idea to shut your windows before you go to bed tonight in Walden and Steamboat Springs, and throughout Routt, Jackson and Grand Counties.  We will certainly provide updates as necessary while the situation continues to evolve.

Another smoky day for the northern Front Range

 Although smoke levels have improved for many parts of Colorado Thursday, that is certainly not the case for the big cities of the northern Front Range.  Moderate to heavy smoke can be found up and down the I-25 corridor from Denver northward to the Wyoming stateline.  And embedded in this geographical area are some areas of significantly heavier smoke.  These are the areas that are directly "down drainage" from the wildfires that have plagued the region for the past few days.  In the image below from the EPA's Fire and Smoke Map, you can see much higher levels of particle pollution in and near Loveland and Longmont (and to a lesser degree, southwest Denver).  It's important for residents of these areas to limit their time outdoors this morning, if possible.  We do anticipate some improvement with the air quality as the atmosphere heats up later this afternoon.  Please remember that an Action Day for Multiple Pollutants remains in effect for this area through at least 4pm today due to high levels of both particle pollution from smoke, and ozone which will be on the increase this afternoon.

Advisories issued for several parts of eastern Colorado Wednesday

 Plenty of smoke to be found across eastern Colorado Wednesday morning.  An Action Day for Multiple Pollutants is already in effect for the northern Front Range region, including Denver, Boulder, Ft. Collins, Greeley, and surrounding areas due to the combination of wildfire smoke and ozone that is expected today.  Unfortunately three sizable wildfires (Alexander Mountain, Stone Canyon, and Quarry) are feeding additional smoke into the I-25 corridor.  Although there is smoke throughout the area, locally heavier smoke can be found in closer vicinity to those three wildfires.  Notice on the below image from the EPA's Fire and Smoke Map the higher levels of particle pollution (in oranges and reds) downwind of those three fires in Loveland, Longmont, and southwestern parts of the Denver metro area.  Gradual improvement with the smoke is anticipated by this afternoon in areas close to the fires as the atmosphere begins to heat up, but keep in mind that ozone will also be increasing this afternoon.  So today might be a good day to just move your plans indoors, if possible.  While outside, be sure to take plenty of extra breaks.

   

Meanwhile, this morning's cold front brought an influx of out-of-state smoke to the eastern plains.  Webcam images and monitoring data reveal moderate to heavy smoke across the northeastern corner of Colorado, so an Air Quality Health Advisory for Wildfire Smoke will be in effect through at least 9am Thursday.  We do anticipate some improvement with the air quality for the eastern plains on Thursday, so hopefully we will not need to extend the advisory beyond 9am.

Webcam image from Holyoke Municipal Airport looking southwest towards the eastern Colorado plains.  Image courtesy of the Federal Aviation Administration

Light, but possibly noticeable smoke can be found in other parts of the state as well.  Some smoke moved into northwestern Colorado overnight from Wyoming.  Fortunately, smoke levels are not terribly high and major public health impacts are not anticipated.  However, if you suffer from asthma or other respiratory ailments, you may want to take it easy today and limit exertion while outdoors in Steamboat Springs, Craig, and Rangely.

Smoke is also likely to have an influence on ozone today.  Ozone is already part of the current alert in the northern Front Range region, but elevated ozone is also possible further south in the Colorado Springs and Pueblo metropolitan areas. Therefore, we have issued an Air Quality Health Advisory for Ozone for those areas today as well.

Throughout this current smoke episode, we continue to advise those impacted to protect your health with plenty of resources available at our Wildfire smoke and health webpage.  You can also monitor the air quality in your area with the EPA's Fire and Smoke Map.

Current air quality advisories for Colorado

Smoke has arrived to northeastern Colorado

An air quality alert is already in place today along the I-25 urban corridor from Denver northward to Ft. Collins due to expected high levels of both ozone and particle pollution from wildfire smoke.  We are now considering raising the flag on an advisory for parts of the adjacent plains to the east as out-of-state wildfire smoke has rushed in with a cold front early this morning (as evidenced by the Akron webcam below).  More information soon to follow.

Webcam image from Akron courtesy of Viaero

 

Heavier smoke tonight for the northern Front Range

The Alexander Mountain and Stone Canyon wildfires have been raging today and produced enormous amounts of smoke.  Most of that smoke has lofted well into the atmosphere, but unfortunately that will change tonight.  Once the sun sets, atmospheric mixing will decrease significantly and smoke will no longer be able to rise into the atmosphere.  At that point, smoke acts like water and seeks its lowest point. In the current situation, two highly populated areas are directly below these two fires.  For the Alexander Mountain, it is Loveland.  For Stone Canyon, it is Lyons.  Both of these communities can expect smoke levels to increase significantly overnight.  Please shut your windows before going to bed tonight as being inside will offer you some measure of protection from the smoke.  

Keep in mind that we are also anticipating an influx of out-of-state wildfire smoke late tonight with a cool front moving in from the north.  So there is a good chance that the entire northern Front Range region from Ft. Collins to Denver could wake up to smoky skies and elevated particle pollution levels Wednesday morning.

New fire start near Lyons, 7/30/24

 In addition to existing air quality concerns, a new start adds to the expected impact on air quality due to smoke from the Stone Mountain wildfire near Lyons. 

Map of approximate location of Stone Mountain wildfire.

This new addition of smoke to the Front Range airshed will further increase the likelihood of significant air quality impacts for locations such as Lyons, Longmont, and nearby areas, as expressed in our earlier post. These conditions are expected to continue through Tuesday and Wednesday, at the very least. 

Stay tuned for additional updates.

Smoke on the Front Range coming from several sources this week

 While a lot of attention on smoke in northern Colorado is focused on the Alexander Mountain fire (and rightfully so), smoke transport from other fires in the western U.S. will also play a role in air quality conditions as the week progresses.

A weak cool front will move through the area on Tuesday night, and is expected to create surface winds out of the north on Wednesday. This will push smoke from the Alexander Mountain fire into areas further south of those that are already affected, and will also bring smoke from fires in upwind states into the mix. On Tuesday morning air quality impacts from the out-of-state fires are already seen across northern and western Wyoming (as well as other states), and with winds shifting to move things toward the south, we expect to see some of that smoke move into Colorado overnight Tuesday and into Wednesday morning.

Map of  smoke (fine particulates) impact on air quality in courtesy of PurpleAir.

By 9 am MDT (15 UTC) on Wednesday the HRRR-Smoke model shows smoke produced locally moving southward from Loveland, CO along the Front Range, reaching at least as far south as the Denver Metro area. Additionally, the smoke currently to our north will move into northern and central Colorado, with the highest concentrations hugging the eastern slope of the Rockies, worsening air quality conditions along the Front Range. This means that in addition to smoke being seen in Loveland and along Highway 34, increased particulate concentrations are expected in Fort Collins, Greeley, Longmont, Boulder, Denver, and surrounding areas.

The impact from out-of-state transport of smoke will also be seen in areas of northern/northwestern Colorado, and on the eastern plains. Though concentrations are expected to be a bit less than will be seen along the Front Range, light to moderate concentrations of smoke are expected across large areas of the state, with potential to affect many outdoor recreation areas and outdoor workers in these areas. We encourage everyone to remain aware and cautious in regard to heavy physical exertion, especially when outdoors, due to the heat and air quality that will affect Colorado in the coming days.

With these expectations in mind, along with temperatures in the mid-to-upper 90's and limited cloud cover, air quality concerns for health impacts due to exposure to both fine particulates (smoke) and ozone will be heightened this week. CDPHE/APCD will keep a close eye on conditions as all of this develops, however it is likely that the Ozone Action Day alert that is currently in effect for the northern Front Range region will be upgraded to an Action Day for Multiple Pollutants as particulate pollution spreads to wider areas.

Heavy smoke in southeastern Larimer County

 Unhealthy air quality can be found across the southeastern corner of Larimer County Tuesday morning due to smoke from the Alexander Mountain wildfire.  EPA's Fire and Smoke Map reveals that the city of Loveland is really getting hit hard with smoke this morning.  

Monitoring data in Loveland shows short-term levels of Unhealthy to Very Unhealthy air quality

We urge residents of Loveland and others in southeastern Larimer County to please take extra steps to protect your health this morning.  Please keep your windows closed and limit your time outdoors this morning, especially if you suffer from heart or lung disease, or are an older adult.  Keeping children inside this morning is also probably a wise idea.  If you still have some N-95 masks, they can be effective against wildfire smoke.  If you start to have health symptoms that lead you to believe that your indoor air quality has also become unhealthy, consider relocating to an area with better air quality if you have the ability to do so.  Of course, please see your health provider if your health symptoms continue to worsen.  You can find all this information along with additional resources at our wildfire smoke and health webpage.

The view from Northern Colorado Regional Airport looking west towards Loveland and the Alexander Mountain wildfire shows the extent of the smoke.  We issued a health advisory for southeastern Larimer County yesterday afternoon which expires at 9am this morning.  However we will be extending that advisory through at least 9am Wednesday with little sign that the fire will be easing up anytime soon.  

Webcam image from Northern Colorado Regional Airport courtesy of the Federal Aviation Administration

Although the advisory will run from 9am today to 9am tomorrow, that does not necessarily mean that the smoke is going to be heavy in southeastern Larimer County all day long.  As the atmosphere heats up, much of the smoke will lift up into the atmosphere which will improve air quality at the earth's surface.  Although the air will not be pristine this afternoon (ozone will likely be elevated), it will certainly be better than what it is this morning.  So if you do need to spend some time outdoors today, this afternoon and evening will be the better option for your health.  Residents in the area should remain updated on the latest information regarding the Alexander Mountain wildfire, including evacuation areas and shelters, at Inciweb's Alexander Mountain Fire webpage.

Alexander wildfire west of Loveland

 The Alexander wildfire is located just to west of Loveland and to the north of state highway 34.  This fire is already producing enormous amounts of smoke, so we have issued an Air Quality Health Advisory for southeastern parts of Larimer County.  Fortunately the bulk of the smoke should remain up in the atmosphere and not create any extended air quality problems through Monday evening, though we could certainly see some quick hits of surface smoke from the plume in Loveland, Timnath, Windsor and southern parts of the Ft. Collins area.  The smoke may get more troublesome and create bigger health impacts later tonight when the smoke begins to "lay down" and seek it's lowest point.  So we should be prepared for the potential for heavy smoke overnight tonight and into early tomorrow morning along State Highway 34 below the fire and eastward into the Loveland area.  We will continue to monitor this wildfire and provide updates as necessary, but if you do reside in the Loveland area you will likely want to keep your windows closed tonight and visit our wildfire smoke and health webpage for additional resources to protect your health.

Image of the Alexander Fire courtesy of the Arapaho Roosevelt National Forest

Heavier smoke possible mid-week for Colorado

Fortunately, it appears that throughout Colorado there is no heavy smoke to be found Monday morning.  Smoke has generally been light to moderate for most areas with heavier smoke remaining well to the northwest of Colorado.  The EPA's Fire and Smoke Map shows where the heavier smoke is currently located:  northern California, southeastern Oregon, southern Idaho, and northwestern Wyoming.  That smoke is mostly coming from the very large fires burning in northern California.  The light to moderate smoke Colorado is currently experiencing has its origins mainly from fires in southern California.  Those fires are large as well, but not producing as much smoke as the fires further north in California.

Heavy particle pollution from wildfire smoke, denoted in reds and oranges, located northwest of Colorado

Regardless, there will be some smoke in the air today which could cause discomfort to some.  This is especially true for the larger metropolitan area around Denver as the wildfire smoke will mix with the regular urban pollution.  If you suffer from asthma or COPD, you may want to slow it down a bit today.  Air quality will likely worsen Monday afternoon as particle pollution levels may begin to increase in combination with the soaring temperatures during the hottest part of the day.  The National Weather Service has issued Heat Advisories today for several locations along the Front Range, including Ft. Collins, Boulder, Denver, Colorado Springs and Canon City, so please do limit your outdoor time this afternoon if possible.

The big question this week:  Will Colorado receive some of that heavier smoke to the northwest?  If so, when?  There are indications that Colorado could tap into some of that heavier smoke by Wednesday.  A weak cool front (we hesitate to say cold front as the temperatures will only drop a few degrees) could move in as early as Tuesday night and may bring some surface air in from the north and northwest.  It's quite possible that air could contain some heavier wildfire smoke for Wednesday, so we will be monitoring conditions very closely over the next few days and provide updates here as the situation continues to evolve.

Jones Fire burning in Mesa County

The Jones Fire is burning in Mesa County approximately 15 miles southeast of Fruita. It is burning in the King's Canyon area of the Black Ridge Canyons Wilderness.

If you are upwind of this fire, you may notice haze in the sky. Satellite imagery shows smoke traveling as far as Glenwood Springs. Overnight, the smoke may become moderate to heavy in valleys and low-lying areas, as daytime mixing decreases. Fruita, Grand Junction, Rifle, and Glenwood Springs may see moderate to heavy smoke by Monday morning.

An Air Quality Health Advisory is in effect for Mesa and Garfield Counties until 9 am Monday morning.

A Red Flag Warning is in effect for Mesa County until 8 pm Sunday evening.

Satellite imagery shows a plume of smoke visible to the west of Grand Junction.

Twin Forks Fire burning in Jefferson County

The Twin Forks Fire is burning in Jefferson County along US-285 near Turkey Creek Road. This fire is less than 10 acres, and crews are on the scene.

While no major public health impacts are expected from this fire, locations near the fire may experience moderate smoke. Unusually sensitive people near the fire should consider reducing prolonged or heavy exertion.

The Jefferson County Sheriff's office is posting updates to X.

Smoke making a quick return to parts of Colorado

 The Park wildfire near Chico, California is receiving plenty of attention this weekend due to it's massive size, rapid spread, and significant damage it has caused.  However, the Park wildfire is not the fire that is going to send smoke into Colorado over the next few days.  The culprits will be fires that are further south in California, along with other parts of the desert southwest.  In the below visible satellite image, note the two large smoke plumes in southern California, along with some smaller plumes in Arizona and Utah.  These are the fires that Colorado will need to monitor in the short-term.  Information on these fires can be found at the InciWeb website.

Visible satellite image courtesy of Colorado State University's CIRA satellite webpage

Sadly, it looks like smoke from this complex of fires will be transported in the direction of Colorado through at least Tuesday.  In the below image showing upper level transport winds for Sunday afternoon, notice the blue shaded area from southern California through the desert southwest and into Colorado.  The wind barbs in this area show winds that are blowing from the southwest to the northeast.  So any smoke that is produced at the wildfires today is expected to head directly towards Colorado.

600 millibar wind model courtesy of Weathernerds.org

Will the entire state be impacted?  Possibly, but there is little doubt that over the next few days the smoke will be more noticeable across the northern half of Colorado.  For this afternoon, particle pollution (PM2.5) may start to increase in Julesburg, Greeley, Ft. Collins, Denver, Boulder, Rocky Mountain National Park and Steamboat Springs.  Smoke modelling is anticipating some of the biggest increases in PM2.5 today across the northwestern corner of Colorado, so a special heads up to those in Craig, Rangely, and those who may be planning to visit Dinosaur National Monument.  To make matters even more dicey, the National Weather Service office in Grand Junction has issued Red Flag Warnings for large parts of western Colorado today, so the threat for wildfires starting in-state is also a distinct possibility.

Improving air quality.......slowly

 The EPA's Fire and Smoke Map shows a lot less orange than it did at this time yesterday.  Wildfire smoke is comprised of fine particulates (PM2.5), and orange on the map corresponds to air quality that is considered "Unhealthy for Sensitive Groups".  So that is good news.  But there is still far too much yellow on the map to our liking, which is considered "Moderate" air quality.  This is especially true for the eastern half of the state where surface level smoke has been stubborn and continues to linger in many areas this morning.  We are happy to see many more green ("Good" air quality) shadings in western Colorado.

Fortunately smoke levels should continue to gradually drop off today, but in the meantime we do suggest taking a few extra steps to protect your health (especially for those east of the Continental Divide).  Breathing in wildfire smoke can have lingering health impacts on your body even after the air quality has improved.  This is especially true for those that do suffer from heart or lung disease, older adults, and children.  Please visit our Wildfire smoke and health webpage to get more information on how to best protect the health of yourself and your loved ones.

Western Slope looking much better while one more day to go east of the divide

 A workweek that has been plagued by out-of-state wildfire smoke may have a happy conclusion as the atmosphere finally gets cleaned out.  Step one of the process has already been completed:  the upper level transport winds from the Canadian wildfires have been shut down.  That means no additional smoke is expected to be pushed into Colorado over the next 24 hours.  Check out this morning's visible satellite image compared to the same time on Tuesday.  Note the milky look of Tuesday's image (left), particularly over eastern Colorado.  Eventually all of that smoke mixed down to the earth's surface and impacted the air that we breathe.  That smoke way up in the atmosphere is largely absent today (right).  So instead of particle pollution (PM2.5) increasing today we anticipate it will decrease, albeit gradually.

Visible satellite image at 7:30am Tuesday (left) vs. 7:30am Thursday (right)

However, folks in the eastern half of Colorado are not out of the woods just yet.  There's still quite a bit of smoke out there this morning and it will take some time to decrease.  We are also still dealing with elevated ozone for the Interstate 25 urban corridor including Ft. Collins, Boulder, Denver, Colorado Springs, Greeley, and surrounding areas.  Additionally, we have been breathing air filled with smoke for several days now.  So we are extending our health advisories for the entire eastern half of the state until midnight Thursday night/Friday morning.  Everyone should continue to follow the health recommendations we have been stressing all week -- reduce prolonged or heavy exertion, limit time outdoors, take extra breaks while being outdoors -- particularly for all of our neighbors that suffer from heart/lung disease, older adults, and children.  And for those that consider themselves healthy, it's still not a bad idea to push off outdoor exercise one more day as Friday should be much improved.  Not only will the smoke continue to naturally mix out of the atmosphere, scattered showers and thunderstorms Friday afternoon should finish off the job of cleaning things up.

For our friends in western Colorado, we are already starting to see the benefits of the changing air mass.  Smoke levels are anywhere from 25-50% lower than they were at this time yesterday.  So although we don't suggest running a marathon today in Aspen, Steamboat Springs or Alamosa, it is safer to spend a bit more time outdoors today.  The air quality improvement is expected to continue throughout the day today and into tomorrow.  The one wild card on the Western Slope today is elevated ozone again for the Grand Valley as the smoke has had some influence in the Grand Junction area the past few days.  We expect ozone to be a bit lower today, but we will be watching it closely and will issue another advisory for Grand Junction if needed.

How about the upcoming weekend?  The good news is that we are not expecting the upper level winds to shift back to the Canadian or Pacific Northwest fires.  However, we will need to keep an eye on upwind wildfires in central and southern California, Nevada and Utah.  However, at this point it looks like any smoke those fires produce should be nowhere near what we have seen so far this week.