August 2, 2015

Weekend Edition: Code Purple PM2.5 AQI in California Due to Forest Fires

A massive wildfire west of Sacramento, California, spanned 54,000 acres Sunday, up from 27,000 acres the previous evening. The Rocky Fire, in Lake, Colusa and Yolo counties, was just 5 percent contained late Sunday afternoon. Air quality levels for PM2.5 reached Code Purple levels, as shown in the AirNow AQI animation. The fires are producing moderate to heavy smoke in northern California. The smoke and burn scars from this fire were visible in today's NASA Aqua MODIS 7-2-1 (top right image) and RGB (bottom left image) products. This smoke is yielding AOD (bottom right image courtesy of NOAA IDEA) values between 0.4-1 over these locations.

In addition multiple areas of light to heavy density smoke in between cloud cover in the Pacific Northwest, British Columbia into the central US was observed. These areas of smoke originated from wildfires in the Pacific Northwest and southern British Columbia.

July 30, 2015

Heavy AOD in the West, Moderate AQI in the East, and Fires in Oregon

Throughout the morning, moderate PM AQI levels were noted spreading from Texas all the way up the east coast (AirNow, top left). As the day progressed, California increased to moderate levels and Oregon reached unhealthy AQI by mid-afternoon. A majority of the Pacific coast and Rocky Mountain states experienced light to heavy aerosol loading, shown in the NOAA GASP animation (top right).

The National Weather Service issued an excessive heat warning and red flag warning for Oregon. The red flag was for fire weather conditions in northwest Oregon and southwest Washington. Hot, dry, and unstable conditions were detected and forecasted for these areas. Oregon currently has multiple active fires. Fire officials can be seen implementing an air attack (Photo by Kyle Reed DFPA , bottom left) on the Cable Crossing Fire which escaped containment and has span of approximately 600 acres. Fires such as these are producing smoke which is likely the cause of the elevated PM AQI levels in Oregon for today. The HMS smoke product (bottom right) shows that Oregon is not the only contributor to aerosols. Smoke from the Manitoba region in Canada is also extending across the border into the northern central U.S.

July 29, 2015


Today's high temperatures and humidity levels influenced the Moderate and Unhealthy air quality levels, code yellow and orange, respectively, that were observed from the Southern Plains to parts of the Northeast region of the U.S., excluding the majority of the Southeast. These moderate and unhealthy levels also affected most of California and part of Arizona and Colorado, as seen in Today's AQI image (top left). Wildfires in the Mississippi Valley, Southern Plains, and in California contributed to the poor air quality levels of the day (AirNow Fires, top right). In that same image we observe some wildfires still burning in Alaska and Canada, and we can see a few sporadic plumes of light smoke traveling east from them. The NAAPS image (bottom left) shows us the wildfires in the different regions and the surface concentration of smoke likely causing the low air quality aforementioned. The wildfires in the Mississippi Valley were also likely the cause of the elevated AOD readings in that region and part of the Southeast, as seen in the MODIS Terra image (bottom right).

July 27, 2015

Remnant Smoke in Alaska, Canada, and Northern US; Saharan Dust in Mississippi Valley Region

Smoke (light to moderate in density) from wildfires currently burning in Alaska are traveling eastward, crossing over into western Canada (see NOAA HMS imagery, top right). Most of the smoke over North America can be seen swirling over most of Canada, presumably remnant smoke from the Siberian wildfires, as mentioned in our previous post. This smoke continues to travel southeast into the Great Lakes and Northeast Regions. The elevated AQI in the north can be seen in today's EPA AirNow Combined AQI Loop (top left). Fires in central and northern California are also producing plumes affecting air quality in the US, traveling as far east as Idaho. The heaviest smoke is over central California, with the lightest coming from the west coast of the state, also presumably remnant smoke from Siberian wildfires. In other news, Saharan dust from last week is still making it's way from the Gulf of Mexico into the southern US, heading north from the Rockies into the Mississippi Valley region. The NAAPS Aerosol Model (bottom) predicts the dust to reach 60 µg/m3 in these areas and 160 µg/m3 over the Gulf.

July 26, 2015

Weekend Edition: Canadian Smoke North of the Border, Haze in the Mid-Atlantic States, Fires in California

NOAA HMS reports a large area of thin remnant smoke exists over north and central/south central Canada, as well asthe northern US states of Montana, North Dakota, South Dakota, Minnesota, Wisconsin, and northern Michigan. Much of this smoke is believed to have been transported from wildfires burning in Siberia (top left image). Fires were reported as well in central and northern California producing light to heavy density smoke heading northeastward through Nevada, Oregon and Idaho. The heaviest smoke is seen in central California (top right image) while majority of the moderate smoke are seen in Nevada heading northeastward, with a small patch of moderate smoke in southeast Oregon. This smoke is yielding AOD between 0.6-0.8 (bottom left image).

In the Southeast and Mid-Atlantic states, AOD retrievals reveal the presence of haze, with AOD ranging between 0.4-0.7, mainly produced from local sources.

July 24, 2015

Good Air Today; Ozone Expected Tomorrow

The air quality today is mostly clear, although there are some areas of Moderate AQI from the southern Plains through the Mississippi Valley and into the Great Lakes seen in the EPA AQI loop below left. The NWS warning map below right shows other problems, though, with the weather ripe for fires in northern Montana and Alaska (the light red) and a good bit of heat around eastern Kansas (the dark red and orange), as well as ozone worries (gray) in central Indiana and northern Kentucky. Several cities in the area have declared air action days for tomorrow, including some out to Ohio and Missouri.

Shown below on the left is the AirNow AQI forecast for tomorrow, showing the areas expecting to get up to Unhealthy for Sensitive Groups. The high pressure system over the southern Great Lakes in the NWS surface analysis shown below right may be contributing to the buildups of both heat and ozone. Even with the high expected to move east tomorrow, there might still be air pulled up from the Gulf of Mexico, which wouldn't help with the heat.

July 23, 2015

California wildfires; Multiple fire weather watches.

Southern portions of Texas and the Mississippi Valley region had moderate AQI levels (AirNow PM AQI loop, top). This is likely due to a high pressure system over the Gulf of Mexico, creating winds that are transporting Saharan dust to these regions. This effect is forecasted to last through Saturday.

There are multiple active wildfires in California probably causing the concentrated areas of moderate PM levels. The location of the fires and associated smoke can be seen in the HMS and NRL combined google earth image (bottom left). These fires have prompted evacuations and highway closures across the state. One bystander captured this image (compliments of, bottom right) of a ravaging fire near Lake Berryessa that currently has a span of 6,000 acres. Also, the National Weather Service has issued fire weather watches for northern Montana and the northwestern corner of Colorado. These watches are indicative of low humidity and strong gusty winds that make an area susceptible to wildfires.