An enormous amount of smoke persists over much of Canada from large wildfire complexes throughout the Northwest Territories surrounding Great Slave and Great Bear Lake. The heavy smoke is visible in the MODIS Aqua rgb image below and is captured in today's AOD retrieval as well.

Nearly all of the US remains affected by remnant smoke from fires in Northwestern US and Canada, with some contribution from fires over East central Nevada. Clear zones include, Alaska, Washington, Oregon, California, Idaho, Nevada, Arizona, the Southeast US from the Mississippi River through North Carolina including all but the Florida panhandle. In today's MODIS Aqua AOD retrieval a large area of hazy aerosols and smoke can be seen across Oklahoma, Arkansas, Missouri, Kansas and Texas. US AQI levels were Moderate for PM2.5 along states on the eastern and southern edge of the smoke cloud, discussed above.

The smoke that has been over the Great Lakes, Mississippi Valley, and Plains States over the past several days is still there, as seen on HMS imagery, below left. This has resulted in the elevated AOD seen in the MODIS Aqua imagery shown below right. Other wildfires burning in Nevada have spread smoke from Nevada through Utah, Wyoming, and parts of South Dakota, Nebraska, and Colorado. The EPA AirNow AQI loop below indicates that the smoke may have affected ground-level air quality, with Moderate AQIs in a swath from the southern Plains through the Mississippi Valley and Great Lakes into the Mid-Atlantic. There is another area of Moderate AQIs in the Pacific Northwest, and northern Rocky Mountains States reaching into British Columbia where a brief spot of AQI Unhealthy for Sensitive Groups flares up mid-afternoon that may be caused by the fires in Washington over the past week.

The fires and smoke seen in Arizona in the HMS imagery above led to poor visibility in the Grand Canyon, as seen in the NPS webcam image below left. For comparison, images on clear and hazy days are shown below right.

The NW Territories Wildfires continue to produce light to heavy smoke, leaking into much of the central US (NOAA HMS Google Earth image, left). Below (right) is a cool photograph taken of the Birch Creek Wildfire last Monday from a bird's eye point of view (courtesy of NWTFire), even though the situation is obviously anything but. Wildfires in Washington State are also producing light to moderate smoke, spreading north into British Columbia and west into the Pacific Ocean. There are no fires in Alaska, however, light to moderate smoke plagues much of the state, presumably transported from the Lake Baikal fires in NE Asia.

The smoke swirling over most of the US has increased PM2.5 AQIs nationwide (EPA AirNow PM2.5 loop, left). Most of the central US as well as some parts of the East and West Coasts were subject to Moderate AQIs today. Levels reached Unhealthy for Sensitive Groups (USG) to Unhealthy on the border of North Dakota and Manitoba, an area covered in smoke and also presumably affected by dust. The NAAPS Aerosol Model (right) predicts the dust surface concentration to reach between 2.58 and 5.12 mg/m^3 over this area.

Rarely has the continent been covered so extensively with smoke. Canadian wildfires and fires in the Pacific Northwest have conspired to make much of the northern half of the US a hazy, smoky mess. The AIRNOW PM2.5 AQI loop today shows that wide areas of Washington, Oregon and Idaho are impacted by smoke at the Code Red (unhealthy) levels. The MODIS AOD image from AQUA today shows a broad band of very high aerosol optical depth in the prairie states of the US. A small bubble of haze was seen to the southeast of Denver and the trajectories show that it is possible that this smoke came from the northwest at higher levels (1.5 and 3 km) above the surface and at low levels (500m) the trajectory wrapped up the front range to the smoke coming from Canada.

At the DISCOVER-AQ project in Denver, we saw this smoke descend to the surface today at three lidar sites (Fort Collins, Platteville and Golden, CO). The result was elevated PM2.5 up to about 20 µg m^-3, not in the hazardous ranges but certainly elevated with respect to what we have seen earlier in the week.

And if there isn't enough smoke here for you, Leonid Yurganov sent along AIRS CO measurements in Siberia from July 17 and Colin Seftor showed the OMPS Aerosol Index readings over the same region today. The Northern Hemisphere is on fire.

Update: July 20, 2014 22:00 MDT

Smoke continues to be the story on Sunday. In AQUA MODIS's AOD image from Worldview (below left), the 1920's Impressionists would have been proud of the painting made by the fires in the Northwest and Canada. VIIRS' palette is a bit more subdued and shows a broad band of AOD = 0.2 across the western states. In Denver, the AERONET DRAGON CIMEL sunphotometers confirm that 0.2 AOD is uniform across the state of Colorado.

Looking at the NOAA HMS Smoke and Fire Product (top left), the small red dots indicate groups of fires, while the light grey areas are smoke plumes. The main one spanning much of Canada and the northern continental United States is from the wildfires that continue to burn in the northwestern US and western Canada. The MODIS Aqua image (top right) shows highly elevated AODs in this region of smoke.

In the Grand Teton National Park at 5:15 MDT (middle left), the visual range is 43 miles. Comparing to the clear-hazy photo to the right, air visibility has been diminished in the area of the plume.

Furthermore, the EPA AIRNow combined AQI animation below also shows moderate AQIs over Southeast, with Unhealthy AQIs seen in the northwest United States and Canada. The current high AQI is in Cottonwood, ID and Twin Falls, ID (153). The area of these high AQIs correspond to the aforementioned wildfires, and has been the case for quite some time, the plume is affecting the air quality in the northern US and most of Canada with not a lot of change in sight.

The HMS smoke imagery, below left, shows the smoke from the fires that have been burning in the Pacific Northwest and the Northwest Territories over the past several days covering a large portion of Canada, the Great Lakes, the northern Plains, the northern Rockies, and the Pacific Northwest. This shows up in the elevated AOD in these regions, shown in the MODIS Aqua image below right.

Some of the fires in the Pacific Northwest can be seen in the MODIS Aqua imagery below left, with names for some of the larger fires also visible. All the smoke is likely contributing to the poor AQIs in the region, seen in the EPA AQI loop below right.



The NRL NAAPS model projects sulfates along the eastern seaboard and Gulf Coast, which could explain the Moderate AQIs in the Southeast, Mississippi Valley, and southern Plains.

NOAA's Hazard Mapping System Fire and Smoke Product reported heavy to light smoke (top left panel) over Canada and the northern United States.The smoke is the cause for the high AOD values retrieved by NASA's MODIS sensor in Aqua (top right panel). The smoke is from wildfires in northern Canada near Great Slave and Great Bear Lake. Relatively newer wildfires in British Columbia are contributing, as well, light to heavy density smoke to this much broader plume (Aqua MODIS true color/rgb image, middle left panel).

Wildfires in the Pacific Northwest are impacting AOD values over this region (middle right panel). Wildfires appearing across Washington state and Oregon are emitting light to heavy density smoke across much of the Pacific Northwest. Light density smoke is seen moving southward across Washington, Oregon, Idaho, Nevada, Utah, Wyoming, and Colorado. Moderate smoke is seen in Washington, Oregon, Idaho, Wyoming, and Utah. Heavy density smoke associated with these wildfires is seen in Washington and Oregon, Heavy density smoke can also be seen descending southward across Montana and Idaho, associated with the wildfires occurring in Canada.

The descending smoke may have impacted the air quality along the Pacific Northwest. Code Yellow to Red (Moderate to Unhealthy) PM2.5 concentrations were reported (Airnow animation below). Idaho experienced in locations near their Idaho CIty and Garden Valley air quality monitoring stations PM2.5 concentrations around 147 and 120 ug/m3, respectively (PM2.5 timeseries courtesy of airnowtech.org).