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.