Hazy skies and light to moderate smoke expected to continue this weekend

 The conditions that much of eastern Colorado and the Front Range has seen over the last several days is likely to persist, at least through the coming weekend and into early next week. A stubborn ridging pattern is in place over the southwestern U.S. and does not look like it wants to budge for the time being. This means that the clockwise flow at upper levels of the atmosphere will likely continue to carry smoke from fires burning in other states in the general direction of Colorado.

NAM forecasted 600 mb winds at 18 UTC (12 pm MDT) on Sunday October 13, 2024, from weathernerds.com, shows a pattern that will likely continue to move smoke from out-of-state fires into Colorado over the next several days. 

What this means for us here in Colorado is that a persistence forecast will take us through the weekend. The haze that has lingered over the last few days and the up-and-down concentrations of fine particulates seen across the eastern slope of Colorado will likely continue, keeping particle pollution in the Moderate AQI category through at least Monday.

We favor these conditions over those experienced by folks who are closer to the fires and receiving much larger amounts of smoke, however we would also welcome a shift in the pattern (or some snow!) that could bring some relief from the gunk that has loitered in our area for long enough.

Keep on taking it easy if you are sensitive to smoke, keep an eye on air quality in your area, and we will keep you informed on any changes in this situation... hopefully sooner rather than later!

Intermittent plumes of smoke moving through the Front Range Wednesday afternoon

 As we had expected, smoke that is aloft in the atmosphere and was headed our way this morning is finding its way to the surface in areas of Colorado. In this scenario, the vertical mixing of the atmosphere is both hurting and helping us.

The low-level turbulence caused by warming daytime temperatures and our abundant Colorado sunshine, and its contrast with the relatively cooler air above the surface, is helping to draw smoke downward and is resulting in increases in particle pollution measured by surface monitors. Yet it is this same motion in the atmosphere that is creating a bank of cumulus clouds along the foothills. As the clouds move east off of the higher terrain, cooling is caused by cloud interactions with their surroundings, and helps to produce localized areas of sinking air that spreads out radially once it hits the ground. These areas of breezy outflow winds are helping to limit the overall impacts of the smoke, and are expected to help disperse surface concentrations as the afternoon progresses. Additionally, the clouds help to reduce the amount of surface heating, and decrease the vigor of up-and-down drafts, potentially limiting the amount of smoke that can be drawn down to surface level.

In addition to all of this, the dense plume of smoke that is the root of the issue continues to be fairly discrete, and is moving through the region... with emphasis on the word 'moving.'

Visible satellite image from CIRA shows the presence of smoke moving through the northern portions of Colorado, with cumulus clouds moving eastward off of the high terrain at 1:40 pm MDT on Wednesday afternoon. 

The overall take-away message is that we are seeing increases in particulate levels at several monitors throughout the region, but we expect those numbers to plateau and taper off as the day progresses. So while hazy skies and notable ups and downs in smoke levels are expected and taking place, we do not currently expect these conditions to persist for extended periods of time. 

As the fires continue to burn, additional plumes of smoke will be created and the potential for repetition of this cycle tomorrow does remain. Stay tuned for additional updates as we watch all of this unfold, and we will continue to share our thoughts and expectations.

Smoke will persist in areas of Colorado, with variable impacts throughout Wednesday

Smoke from out-of-state fires will continue to move into Colorado on Wednesday, mainly affecting eastern areas of the state. On Wednesday morning, surface concentrations remain in the Moderate range for many areas, with the highest numbers found on the plains and in the northeastern corner of Colorado. However higher concentrations are found in the Nebraska panhandle, and the first light images on satellite reveal the presence of smoke moving in from the northwest. The reason that the numbers shown on surface monitors do not match the location of smoke seen on satellite is because the smoke remains aloft, and has not reached the surface yet. As daytime mixing increases, we expect that smoke to be transported downward and an increase in monitored concentrations to be seen. Along with rising levels of fine particulates, degradation of visibility is also expected, causing hazy skies throughout many areas east of the Continental Divide.

The map of fine particulate concentrations from purpleair.com shows Good to Moderate impacts from wildfire smoke in areas of the Front Range, and in eastern and northeastern Colorado.

Smoke from fires in upwind states is seen in visible satellite imagery from CIRA as it is transported southward into Colorado from Wyoming (image from 8:20 am MDT on Wednesday, October 9, 2024).

Continued transport of smoke is expected throughout the day on Wednesday. While our primary area of focus for impacts from smoke is the areas on the eastern plains, similar conditions may be seen periodically along the Front Range as well. Though the surface levels may fluctuate throughout the day and affect different areas at different times, we expect Moderate conditions to be seen in widespread areas of Colorado, reaching levels that are Unhealthy for Sensitive Groups periodically.

The Air Quality Health Advisory for the eastern plains has been continued on Wednesday, and we encourage individuals who are sensitive to smoke to take health precautions to reduce exposure, and to reduce or avoid heavy exertion in all areas where smoke is present, especially areas currently under the Advisory.

As conditions continue to evolve, updates on observed impacts and future expectations will be posted.

Widespread wildfire smoke across eastern Colorado

Unfortunately many eastern Colorado residents are waking up to hazy skies Tuesday morning with plenty of wildfire smoke across the region.  Alerts and advisories remain in effect for that long stretch of Interstate 25 from Pueblo northward through Colorado Springs, Denver, Ft. Collins, and to the Wyoming state line.  The good news for these areas is that there should be some steady improvement throughout the day today.  Any improvement will be slower for areas further east on the plains.  Basically for areas east of the Interstate 25 corridor and north of Interstate 70, particle pollution will likely be elevated through tomorrow morning.  You can get all the details on advisories for your area at our website.  Additionally, you can keep track of air quality monitor readings at the EPA's Fire and Smoke Map and get helpful information to protect your health at CDPHE's wildfire smoke and health webpage.

Smoky sunrise over New Raymer.  Image courtesy of https://www.viaero.com/weather-cameras

Air Quality Health Advisories/Alerts posted for parts of eastern Colorado

 With wildfire smoke now increasing across eastern parts of Colorado, Air Quality Health Advisories/Alerts have been issued.  Although increased particle pollution is anticipated throughout most of eastern Colorado, the biggest concern in the short-term is along and near the Interstate 25 corridor from the Wyoming state line southward through Ft. Collins, Denver, Colorado Springs, and as far south as Pueblo.  Expect smoke to continue to increase across the region and likely linger through at least Tuesday morning.  At this point, we do think there will be some slow improvement Tuesday afternoon but some uncertainty does continue in the forecast.  Please stay tuned here for the very latest information as the situation continues to evolve.

Smoke on the horizon looking northeast from Rocky Mountain Metro Airport in Broomfield. Image courtesy of the Federal Aviation Administration

Wildfire smoke headed towards northeastern Colorado

 As northerly winds spread across northeastern Colorado on Monday, wildfire smoke in Wyoming is poised to move in.  Expect particle pollution to increase throughout the region on Monday, with the areas in northeastern Colorado most impacted likely to be bounded by the Wyoming stateline to the north, the Nebraska and Kansas statelines to the east, Interstate 70 to the south, and the foothills to the west.  This will result in many towns/cities being impacted by worsening air quality on Monday, including Sterling, Ft. Morgan, Greeley, Ft. Collins, Boulder, and Denver.  Please visit CDPHE's wildfire smoke and health page for more information on how you can protect your health.

Visible satellite image Monday morning of heavy smoke in southeastern Wyoming

The biggest area of concern will be areas along the Interstate 25 urban corridor from Denver northward to Wyoming, along with the foothills just to the west of this stretch of Interstate 25.  This is where we could see longer duration, higher concentration smoke that could last from late Monday afternoon into Tuesday.  Advisories/Action Day Alerts may be required for this area, so please remain updated with the latest information on CDPHE's advisory webpage. 

Air Quality Health Advisory issued for parts of western Colorado

 Hazy skies and elevated particle pollution are greeting folks on the West Slope Monday morning.  An Air Quality Health Advisory for Wildfire Smoke has been issued for Mesa, Delta, and Montrose Counties.  With that in mind, we ask residents in these counties (particularly in valley locations, including Grand Junction, Delta, and Montrose) to take it slow this morning.  The good news is that as the atmosphere heats up this afternoon, we are anticipating surface smoke concentrations to decrease which will result in an improvement in air quality.

A hazy sunrise over Grand Junction.  Image courtesy of the Federal Aviation Administration

  

Three large wildfires upwind of us are the main cause of smoke this weekend: the Yellow Lake Fire in Utah, and the Pack Trail Fire and Fish Creek Fire in Wyoming. Particulate Matter concentrations are Moderate at almost every location in Colorado. 

Today, the heaviest smoke is expected on the Western Slope, especially along the I-70 corridor. Grand Junction, Palisade, Delta, Montrose, Rifle, Glenwood Springs, and Aspen will likely see the worst of it. Expect lingering smoke overnight Sunday night into Monday on the western slope. 

As for eastern Colorado, the HRRR-Smoke model forecasts widespread smoke moving in on Monday. The smoke is expected to move in from Wyoming Monday morning, pushing south through the day on Monday and overnight into Tuesday.

For information on how to protect your health during a wildfire, visit our website.

Satellite imagery shows smoke (in gray) visible over Utah, Colorado, and Wyoming.

The HRRR-Smoke model's near-surface smoke product shows smoke pushing through eastern Colorado on Monday.

Smoke and Red Flag Conditions Today

We know what you're thinking - "Shouldn't fire season be over by now?" Sure, October is a little late for all this smoke and heat. While we wait for Autumn to get its act together, let's dig into today's smoke situation.

First, Smoke from the Yellow Lake Fire in Utah has moved into Western Colorado. Purple Air sensors show elevated particulate matter concentrations in Meeker, Rifle, Glenwood Springs, and Aspen. Satellite imagery shows smoke over Rio Blanco, Garfield, Mesa, Pitkin, Delta, and Gunnison counties. In these locations, you might consider limiting exercise, staying indoors, and closing your windows to reduce how much smoke you're breathing in. Additionally, you can find more tips on our website to protect your health from smoke.

Second, on the Front Range, the air is comparatively clearer, but, light smoke still lingers. Fires are still burning in Wyoming, and that smoke is still moving into Colorado. Particulate matter is expected to be in the Good to Moderate range today in Fort Collins, Greeley, Denver, and Colorado Springs.

Finally, hot, windy, and dry conditions are on tap today for a large section of Colorado. Several counties- primarily in northeast Colorado- are under a Red Flag Warning until 7 pm Saturday evening. Any new fires that spark may spread rapidly. 

CDPHE is monitoring the situation and will provide updates as necessary. 

Smoke (in gray) is visible in eastern Utah and western Colorado. The eastern plains, in comparison, are much cleaner.

Outlook for the weekend brings uncertainty and conflicting expectations, in regard to smoke in Colorado

 As is often the case in Colorado, especially during the ups-and-downs that come with fall weather in our state, the weekend ahead offers a mixed bag of pros and cons with regard to smoke. Smoke and fire models have been somewhat overplaying fire activity, but also mildly underestimating particulate concentrations; making it difficult to put too much confidence in the results that they produce. 

Weather models have a bit more agreement in terms of wind and temperature patterns, however that too ushers conflicting expectations. Saturday looks to have above average temperatures, low humidity, and breezy to gusty winds. These conditions heighten concerns for fire danger. This may not mean too much in Colorado due to the pleasant lack of fire activity in our state (barring any new starts, of course). Yet the same conditions are likely to affect neighboring states like Wyoming and Utah, so the same breezy winds and good atmospheric mixing that may help to decrease the smoke that is currently lingering in pocketed areas along the Front Range may also usher in smoke from those fires that are active elsewhere, upwind from us.

A cool front looks to arrive late on Saturday and may help to lower temperatures a bit, however it will also limit vertical mixing and decrease the dispersion of any lingering smoke from transport on Saturday. Gradual warming on Monday and Tuesday will be caused by the persistence of a ridging pattern in the southwest U.S., yet may also be conducive to continued transport of smoke into our region.

The good news in all of this is that the overall concentrations of fine particulates have remained in the Good or low-Moderate range of the AQI scale, and appear to persist in a similar fashion. The takeaway message here is that while we cannot rule out some influence of smoke on our air quality, no significant impacts are expected. 

Though pockets of low-moderate concentrations of fine particulates linger, and may persist during the coming weekend, the map of surface air quality due to particulates (smoke) from fire.airnow.gov shows mainly good air quality in Colorado.

As always, we will keep an eye on things and put forth any pertinent information that arises.

Smoke lingering in Colorado, overall improvement expected

The smoke that was expected to move into Colorado from the north on Wednesday moved further to the east and dispersed along the cold front that is heading our way. This spared many areas of Colorado from the higher particulate levels that appeared possible in yesterdays forecast. Great news! 

As the cold front enters Colorado from the northeast, it may push some of the smoke back toward our state and bring hazy skies and light concentrations of smoke to areas of eastern Colorado, pushing southward over the eastern plains throughout the day on Thursday.

Smoke from fires in western Wyoming made its way into areas of northwestern Colorado, and appears to be lingering in some of the mountain valleys in Routt, Grand, Moffat, Rio Blanco, and other northwestern counties. However, surface monitors still show minimal surface impacts, even in these areas.

The map of surface air quality due to fine particulate matter (smoke) from fire.airnow.gov in the morning hours of Thursday, October 3rd, shows only light to moderate impacts from smoke, due to wildfires actively burning in other states to the north and west of Colorado.

Breezy winds throughout he day on Thursday will help to disperse the smoke that is present and limit overall concentrations from rising significantly from the current levels. Additionally, as the trough associated with the cold front moves eastward, a shift in the large-scale wind pattern looks to push things northward again, and decrease the likelihood of more smoke coming our way on Friday and into the weekend.

Though haze and light concentrations of fine particulates are expected to persist, particularly in the areas mentioned above (with some pockets of Moderate air quality remaining possible too), no significant impacts are anticipated; and the trend appears to be headed in the right direction. We will keep monitoring conditions and updating expectations as things develop, however the current outlook lets us anticipate clearing skies and fresh autumn air in the coming days.

Those that are particularly sensitive to particulate pollution may continue to consider reducing activity on Thursday, especially folks with preexisting respiratory ailments. Yet the potential for worsening conditions appears to have been avoided, and continuing improvement is expected. More info will be reported here if things change from the current outlook, but we hope that, as the old saying goes, 'no news is good news,' over the coming days.

Lingering Smoke With More to Come This Week

 Smoke is lingering on the Front Range this morning. Particulate matter concentrations are Moderate in Denver, Fort Collins, and Greeley. Fires continue to burn in Idaho, Utah, and Wyoming, and smoke could move into Colorado starting Wednesday afternoon.

A cold front is expected to move into Colorado on Wednesday evening, and smoke could arrive alongside it. According to the HRRR-smoke model, smoke may arrive beginning Wednesday afternoon. Counties along the Wyoming border could see smoke by late afternoon, and smoke will continue to push south Wednesday evening, and overnight into Thursday. Northern Colorado could wake up to noticeable haze and smoke on Thursday morning. Smoke may persist throughout the day on Thursday.

It's unclear exactly how much smoke will arrive, but what is clear is that northern Colorado is likely to experience the highest concentrations. Craig, Steamboat Springs, Walden, Fort Collins, Greeley, and Denver could all be impacted. If you are in these areas, you might consider limiting exercise, staying indoors, and keeping your windows shut to minimize your exposure to smoke.

We will update the blog on Thursday as conditions develop.

Visible satellite imagery shows smoke in Wyoming, that may move into Colorado Wednesday and Thursday.

Front Range smoke

 Yesterday's cold front has transported smoke into the Front Range region from wildfires in Wyoming.  In fact, it is a bit more smoke that we had originally anticipated as the fires were more active yesterday that expected.  Although fine particle levels are not quite high enough for any advisories, people who suffer from heart or lung ailments in Denver, Boulder, Longmont, and Ft. Collins may want to skip that outdoor exercise this morning.  Any improvement with the air quality today will likely be slow as atmospheric mixing will not be very good.

The EPA's Fire and Smoke Map shows moderate (yellow) levels of particle pollution at air sensors throughout the Front Range region

Yellow Lake fire could bring smoke to Colorado

 We will be closely watching fire activity on the Yellow Lake wildfire in northern Utah on Monday.  If the fire gets active and produces smoke, it could be sent into western Colorado tonight and during the day on Tuesday.  The image below is courtesy of the Uinta-Wasatch-Cache National Forest Facebook page where you can also get updated information on the fire's behavior.

In addition to smoke from the Yellow Lake wildfire, a cold front could bring some smoke into northwestern Colorado tonight from fires in Wyoming.  All that being said, surface concentrations of PM2.5 (fine particles, which are the primary health risk from transported wildfire smoke) could very well be elevated tonight/Tuesday from northwestern Colorado (Craig, Meeker, etc.) southward into the Grand Valley which could impact Grand Junction.  In these areas, you may want to keep an eye on air quality monitors on the EPA's Fire and Smoke Map.  If you want to play it safe, close your windows before going to sleep tonight.

We will continue to monitor the smoke and post air quality advisories here, if necessary.

Photo of the Yellow Lake Fire courtesy of the US Forest Service, Unita-Wasatch-Cache National Forest Facebook page.

Potential for smoke moving into Colorado Thursday, 9/26/24

 While Colorado enjoys clean air and very low wildfire activity, folks in central Arizona have still been contending with smoke from the West fire, and several others in this region. The satellite image below shows a good amount of smoke emanating from the West fire on Tuesday, partially due to burning operations in order to strengthen containment lines.

A large plume of smoke can be seen in this satellite image from the Cooperative Institute for Research in the Atmosphere, coming from the West fire, located to the east of Prescott, Arizona on the evening of Tuesday 9/24/24.

Hot and dry weather conditions may again allow for significant smoke production from the West fire (and others in this area) on Wednesday and Thursday, and an upper level ridging pattern in the atmosphere may allow for some of that smoke to be transported into Colorado. While significant health impacts are not anticipated, hazy skies and light concentrations of smoke may be present in areas on the western slope of Colorado, with these conditions possibly reaching the Front Range as well.

If conditions develop that warrant further messaging concerning this smoke and any impacts that it may have, updates will be posted here. If air quality in your area is a concern, check your local AQI on the AirNow fire and smoke map, and visit the APCD webpage for more info on particulate concentrations and health recommendations.

New wildfire start in Larimer County

 The Pearl wildfire is burning in northern Larimer County about 5 miles to the northwest of Red Feather Lakes.  Mandatory evacuations have been issued so please do heed local officials and emergency response personnel if you are in the area. Smoke concerns should be minimized due to the population being moved out and the fire's relatively small size (approximately 138 acres as of 4:10 PM MDT).  However, brief periods of heavy smoke will be possible throughout the area due to the gusty and erratic winds anticipated through this evening. 

GOES-16 satellite image of the Pearl wildfire in northern Larimer County

Northwestern Colorado wildfire

A wildfire is located near the Moffat/Rio Blanco county line. Fortunately it is isolated and in a remote area, so should cause no public health impacts.  However you may see some smoke if you are travelling on State Highway 13 between Craig and Meeker. 

Light to moderate smoke will linger in Colorado on Friday with gradual clearing, 9/13/24

Smoke from wildfires in the western U.S. has made its way into Colorado, but thankfully, concentrations seen across the state have remained fairly tolerable. Fine particulate monitors throughout the state show good to moderate air quality, with much of the residual smoke being seen in the central mountains and along the Front Range. 

Map of fine particulates (smoke) from fire.airnow.gov shows good to moderate air quality around the state of Colorado on Friday morning.

These conditions are likely to persist throughout the day on Friday due to a bit less wind, and atmospheric mixing that is slow to get going in the cooler air mass that has settled in. The good news is that as this air mass moves out, upper level winds will shift and limit the transport of additional smoke into our area. We expect hazy skies on Friday, with generally good to moderate air quality to remain in the current trend.

While significant public health impacts appear unlikely, those who have preexisting health conditions like asthma and COPD, and those who are sensitive to fine particulates (smoke) should continue to stay aware of the conditions in their area and consider health precautions to decrease the likelihood of adverse health effects. 

Smoke expected to move into Colorado Thursday, into Friday... but how much? 9/12/24

Models continue to indicate that smoke from fires across the western U.S. will move into Colorado Thursday evening and into Friday, however, so far the timing and severity of those impacts has not aligned with the model's predictions. It is suspected that cloud cover and increased relative humidity within the cooler air mass that is moving through the northwest states has limited fire activity, and breezy winds are helping to disperse smoke more effectively than the model is able to account for. 

This is NOT to say that the threat of smoke moving into Colorado does not remain, it is simply to underscore the uncertainty of the timing and overall impact of this influence.

An uptick in particulate counts has been seen in in western Colorado, including in Grand Junction, where monitors are showing Moderate air quality. However the conditions seen to the west and southwest remain less concerning than anticipated. 

Map of fine particulate monitors from fire.airnow.gov shows mainly Moderate conditions in Colorado and areas immediately upwind. Potential remains for heavier impacts to develop, however the severe impacts shown in early model runs on Thursday have not come to pass on Thursday afternoon.

This is all very encouraging for the moment, but does not mean that we are totally in the clear. The conditions seen in areas closest to the many fires in other states confirm that smoke is still being produced, and is still likely to move toward Colorado Thursday night, and may settle in by Friday morning.

Those who are sensitive to exposure to smoke should continue to reduce heavy exertion and take precautionary measures to reduce negative health impacts from smoke. You can find information about potential health complications and ways to reduce exposure on CDPHE's website, or by clicking on the Health Information tab at the top of this blog page.

We will continue to monitor conditions closely, and will report significant changes and expectations as they emerge.

Smoke arriving Thursday from large wildfires upwind of Colorado, 9/12/24

The smoke expected to infiltrate Colorado from areas to the west and northwest of our state has begun to arrive. Folks in western and southwestern Colorado have woken up to hazy skies, and monitors are already showing Moderate concentrations of fine particulates.

Map from fire.airnow.gov shows Moderate air quality conditions creeping into Colorado, with higher levels of particulates to the west.

We expect that additional smoke will arrive in Colorado throughout the day, moving from west to east. The greatest impacts on Thursday are expected in western and northwestern Colorado.

As model depictions, satellite observations, and ground monitors help us to track the movement and impact of this smoke, more information (possibly including Air Quality Health Advisories) will be posted here. Stay tuned for mor information as the situation develops.

Another increase of wildfire smoke appears to be on the way

 We are closely monitoring wildfires in states to the west of Colorado as the meteorological conditions are looking increasingly favorable (or unfavorable, depending on how you look at it) for smoke concentrations to increase across Colorado over the next 24-48 hours.

Let's start with wildfires in southern California.  Up to this point this summer, southern California wildfires have not had much impact on our air quality here in Colorado.  However, that may soon change.

Satellite imagery from Tuesday, September 10th of large wildfires and heavy smoke in southern California.

Smoke from these wildfires is already hanging over Nevada, Arizona and Utah.  With southwesterly winds aloft, this smoke will likely be pushed over western Colorado by Wednesday evening.  That smoke will likely stay up in the atmosphere Wednesday night and not cause any issues, but bigger changes are more likely to occur on Thursday.  As the atmosphere heats up during the day on Thursday, some of that smoke will likely mix down to the surface across western Colorado.  Meanwhile, a very strong upper level low pressure system is going to shift the upper level winds over the southern California wildfires from northwesterly to southwesterly which will transport additional smoke in the direction of Colorado.

The GFS 600 millibar model late Thursday night shows the wind flowing from southern California into Colorado.

How much smoke will Colorado receive on Thursday?  That is still unclear at this point.  The good news is that it should be a pretty breezy day across much of the state which should limit smoke from accumulating too much at the surface of the earth, but we should anticipate hazy skies and at least some moderate concentrations of smoke (especially across the northern and western halves of Colorado).

Unfortunately, it is not only the southern California wildfires that may have an impact on our air quality.  Long duration wildfires in Oregon and Idaho may also make their presence known by Thursday night.  The good news is that smoke should impact a smaller section of Colorado, generally the northwestern part of the state.  But that smoke could no doubt be noticeable by Friday morning in places like Craig, Rangely, and Meeker.

You can get more information on wildfires throughout the western US at InciWeb.

So we do advise Coloradoans throughout the state to keep checking this blog and remain up-to-date on the latest information as conditions continue to evolve.  Although health advisories are not necessarily imminent, residents who are especially sensitive to wildfire smoke (asthma, COPD, etc.) should start making preparations now to limit exertion and outdoor activity starting Thursday and continuing into Friday.  You can learn more about ways to protect your health at our wildfire smoke and health webpage.

Looking on the bright side, the storm system that will transport this smoke into Colorado will also bring a cooler and less dry air mass to the wildfire locations upwind.  We are hopeful that air mass change will decrease the fire activity and smoke production, which in turn would decrease the threat of poor air quality in Colorado in the days and weeks ahead.

Possible Smoke Tuesday Afternoon

Large wildfires continue to burn in Oregon, Idaho, and Montana, and heavy smoke persists. While Colorado's air is comparatively clean, the northern Front Range may see some smoke this afternoon.  

The HRRR-Smoke model shows a brief uptick of smoke in eastern Colorado arriving Tuesday afternoon. By noon, The Northern Front Range may begin to see smoke. Throughout the afternoon, smoke is expected to move south. The highest chance of smoke will be north of the Palmer Divide. Smoke is likely to dissipate by Wednesday.

No major public health impacts are expected, but those with asthma or other respiratory ailments may consider reducing prolonged or heavy exertion today. 

Heavy smoke is visible north of Colorado.

The HRRR-Smoke model (6 am Tuesday through 6 am Wednesday) shows smoke moving into the Northern Front Range beginning Tuesday afternoon.

Prescribed fires expected this week

 As we head into the autumn months and the threat for wildfires decreases, expect to see an increase in prescribed fire activity across the state.  This is especially true with larger landscape burns that often occur during the early autumn months before the snow starts to fly.

This week, some sizable broadcast burns are expected in the southwestern part of Colorado.  The US Forest Service will be conducting a 1000+ acre burn today between Chimney Rock and Arboles (see map below).  Due to the remote location of this burn, public health impacts are not anticipated.  However smoke will likely be visible today on that section of State Highway 151.  You can find more details on this burn and additional information from the San Juan National Forest at InciWeb.  The southwest district of the Bureau of Land Management will also be conducting prescribed burns this month in southwestern Colorado.

Please be sure to stay up-to-date on all the larger burns that will be conducted across Colorado over the coming months by clicking the Prescribed Fire Map tab above.  You can view all the current smoke management permits for this calendar year along with weekly burn notifications.

Location of the "Southern HDs" prescribed burn in southwest Colorado

Heaviest smoke continues to avoid Colorado

The EPA's Fire and Smoke Map and GOES-18 visible satellite image (see below) show exactly where the active wildfires and heavy smoke are located.  Colorado has been fortunate in recent weeks with the vast majority of that smoke remaining north of the state.  The question becomes, how long will our luck hold out?  The good news is that, at least in the short-term, the really heavy smoke will remain north and northwest of Colorado.  However, that does not mean that we will remain completely unscathed.  In fact, a quick smoke intrusion is looking increasingly likely for the northeastern corner of Colorado on Tuesday.  This would include the northern Front Range region (Ft. Collins, Boulder, Denver) along with the adjacent plains (Julesburg, Sterling).  So expect increasingly hazy skies in this part of Colorado on Tuesday along with elevated levels of particle pollution.  We are not expecting major health impacts at this time, but if you do suffer from heart/lung disease you may want to take this into account if you do plan on spending time outdoors on Tuesday.  More information can be found on our wildfire smoke and health webpage.

EPA's Fire and Smoke Map shows elevated particle pollution (in yellow, orange and red) across the northwestern U.S.

GOES-18 visible satellite image shows heavy smoke originating from wildfires in Oregon, Idaho and Montana

Light smoke lingers in Colorado, likely to continue through the weekend, 9/6/24

While wildfire activity remains pleasantly quiet in Colorado and fine particulate levels continue to be in the Good to Moderate range, our neighbors to the north and west are still contending with areas of thick smoke from fires in Wyoming and Idaho. The heaviest smoke remains in the areas close to the fires, blanketing central Idaho and northwestern Wyoming.

HRRR-Smoke map of smoke near the surface in the northwestern United States, valid at 18 UTC (12 PM MDT) September 7, 2024.

With an atmospheric ridging pattern over the mountain west, upper-level winds will likely carry much of the heaviest smoke to the north and east of Colorado, however light to moderate concentrations of smoke from the fires closer to us may filter into northern and eastern portions of the state over the next several days. 

NAM 600 mb winds from weathernerds.com, valid at 18 UTC (12 pm MDT) on Saturday, September 7th, 2024.

No significant public health concerns due to smoke are anticipated at this time, with this pattern likely to stay in place through the coming weekend. Overall, we expect hazy skies and light to moderate concentrations of fine particulates, primarily in northern and eastern areas of Colorado.

Potential for smoke moving into eastern Colorado, 9/5/24

 For the moment, Colorado is enjoying clean air while neighboring states are experiencing elevated levels of fine particulates due to the transport of wildfire smoke.

PurpleAir map of elevated levels of particulates (smoke) in states surrounding Colorado.

Smoke models indicate that some of this smoke may move into eastern Colorado Thursday afternoon and evening. 

HRRR-Smoke map of potential transport of smoke into eastern and northeastern Colorado at 6 PM MDT Thursday.

Little in the way of public health impacts are expected, and concentrations are expected to remain light to moderate. However areas of haze are possible, especially in northeastern portions of the state. Keep an eye on conditions in your area and those who are sensitive to smoke exposure may consider health precautions in areas where smoke becomes apparent.

Light concentrations may linger on Friday morning, however the large-scale wind flow pattern looks to limit additional transport on Friday. Potential for incoming smoke returns on Saturday, and updates on expectations will be posted here as the situation evolves.

Possible Smoke Arriving Midweek

Large fires in Idaho continue to produce heavy smoke, some of which may reach Colorado this week. Smoke could begin to move into eastern Colorado starting on Wednesday. Eastern Colorado may notice haze and light smoke, beginning Wednesday and continuing through Thursday. 

No major public health impacts are expected, but CDPHE is monitoring the situation and will issue an Air Quality Health Advisory if it becomes necessary.

Visible satellite imagery shows heavy smoke in Oregon, Idaho, and Montana, upwind of Colorado.

Light Smoke Lingering Through Labor Day

 Smoke from out-of-state wildfires made its way to Colorado on Friday. Sunday morning, smoke is lingering on the Front Range and in northern Colorado. 

This morning, many monitors are reporting Moderate Particulate Matter. As atmospheric mixing kicks in Sunday afternoon, smoke concentrations should decrease. Although no major public health impacts are expected from this smoke, unusually sensitive people may consider reducing prolonged or heavy exertion today.

The HRRR-Smoke model suggests that light smoke and hazy skies may linger through Monday. 

EPA's Fire and Smoke Map shows light smoke in Colorado.

The HRRR-Smoke Model shows smoke dissipating on Sunday afternoon, and light smoke remaining on Monday.

Here Comes the Smoke

 Smoke has begun to make its way into Colorado this morning. Satellite imagery shows light smoke in northwest Colorado and on the Front Range. Fortunately for Colorado, the heaviest smoke is upwind in Wyoming, Utah, and Idaho.

In northwestern Colorado, particularly Moffat County, light smoke and haze may be noticeable this morning. Smoke is expected to dissipate as atmospheric mixing increases this afternoon.

On the Front Range and eastern Plains, smoke may continue to mix down to the surface throughout the day. The HRRR-Smoke model shows light smoke developing Friday afternoon. In southeast Colorado, there may be noticeable haze and light smoke. 

No major public health impacts are expected, but you may consider taking steps to protect your health from wildfire smoke today. If conditions worsen, CDPHE will issue an Air Quality Health Advisory.

Visible satellite imagery shows heavy smoke in Idaho, moderate smoke in Wyoming and Utah, and light smoke in Colorado.

The HRRR-Smoke Model predicts smoke on the eastern Plains this afternoon. As daytime atmospheric mixing increases, smoke could mix down to the surface.

Potential Smoke on Friday

As of Thursday morning, the anticipated potential smoke hasn't panned out. No major fires broke out in Wyoming yesterday, so Colorado is currently in the clear.

Friday, smoke may return for some of the state. Smoke from the large fires burning in Idaho is expected to move south into Wyoming, Utah, and parts of Colorado beginning overnight Thursday night through Friday morning. Northwestern Colorado may wake up to hazy skies and light smoke. On the Eastern Plains, haze and light smoke are possible as well. 

At this time, no major public health impacts are expected. CDPHE is monitoring the situation and will issue an advisory if necessary. 

Heavy smoke is visible in Idaho and western Wyoming. This smoke may move into Colorado overnight Thursday into Friday. 

Potential Smoke at the End of This Week

Smoke may be back in the picture this week. While there are still many uncertainties, northern Colorado may experience smoke beginning Thursday.

A Red Flag Warning is in effect for much of Wyoming. As of this morning, the fires in Wyoming are mostly contained, but any new fire starts could spread quickly. Northerly winds are expected to develop on Thursday morning, meaning any smoke from these potential fires could reach northern Colorado.

The HRRR-Smoke model indicates that smoke from Idaho could move into northern Colorado by Friday morning. It is still too early to tell with certainty which locations will be most impacted, but CDPHE will continue to monitor and update the smoke blog as this week progresses.

Satellite image from Tuesday afternoon shows heavy smoke in central Idaho. Smoke from these fires may make it into Colorado on Friday.

Brush fire near Roxborough Park

 A brush fire is burning near the Denver Water treatment plant in Roxborough Park.  There are no immediate air quality health concerns but please avoid the area and we will continue to monitor the situation. 

Smoke moving into northern Colorado on Thursday from out-of-state fires, 8/22/24

Wildfire activity in Colorado remains relatively quiet, and thankfully smoke impacts from the Goltra fire near Golden are very minimal on Thursday morning. 

However, fires in Wyoming (and other upwind states) remain active, and winds out of the north have drawn smoke into northern Colorado. Monitors on the EPA's fire and smoke map show recent, significant increases in particulate levels in Greeley and the surrounding areas. As these conditions persist during the daytime hours on Thursday, smoke may move into other areas including northern portions of the east plains, as well as along the Front Range, potentially affecting Fort Collins, Longmont, Denver, and areas in-between.

EPA's fire and smoke map indicates smoke from upwind states is being drawn into northern portions of Colorado on Thursday August 22, 2024.

As atmospheric mixing increases on Thursday, along with developing rain showers and thunderstorms throughout the region, surface concentrations may decrease throughout the day. Weather models also indicate that winds will shift during the late evening and overnight hours and limit the continued transport of smoke into Colorado. 

For the time being, we expect that the Air Quality Index (AQI) due to fine particulate concentrations will remain in the Good to Moderate range, though short-term increases in smoke levels are possible. We recommend limiting time outdoors and reducing heavy physical exertion if possible in areas affected by smoke, especially for folks who are sensitive to particle pollution. Take precaution to protect you health from smoke exposure in areas where smoke and particulates are present.

We will continue to monitor conditions closely, and will post further updates as information and expectations continue to develop.