Weekend of Smoke: Aug 18-19

Washington and north Idaho experienced the worst smoke of the summer (so far) during the weekend of August 18-19. The smoke reduced visibility to a mile or less in many areas and drove air quality into the "unhealty" or "hazardous" range across the Pacific Northwest. By Sunday, the smoke forced many residents indoors. Reduced visibility from the smoke even caused delays at Seatac airport.

The smoke produced an eerie feeling of darkness during the middle of a summer day. Motorists used headlights throughout the day due to the poor visibility. Check out the picture of Coeur d'Alene at 4 PM on Sunday the 19th.

August 19 at 4 PM: Vehicles Using Headlights. Idaho Transportation Department Camera in Couer D'Alene ID

At times, it was tough to see the sun through the thick veil of smoke. The sun is the little bright dot to the left of the radar tower. This picture was taken at the National Weather Service Office just west of Spokane at 6 PM on the 19th. The nearby Spokane International Airport reported 1 mile of horizontal visibility at the time of this photo. 

August 19 at 6 PM: NWS Spokane.

Where are the fires producing all of this smoke? The map below shows the "hot spots" detected by satellites. The red and orange dots indicate active fires across British Columbia, Washington, and Oregon. Other large fires are burning over northern portions of Vancouver Island.

The map below is a computer simulation produced by NASA that forecasts smoke in the atmosphere. The oranges, reds, and pinks indicate high concentrations of smoke. Atmospheric winds have created a huge reservoir of smoke over the western United States with some of the highest concentrations of smoke over Washington, north Idaho, and southern British Columbia.

NASA/GMAO - GOES-5 Forecast CO Biomass Burning valid 00 UTC 20 August, 2018

Air quality across the Pacific Northwest was affected by the smoke. The red dots on the map below represent sensors reporting "Unhealthy" air quality. The purple and dark purple dots are indicative of "Very Unhealthy" and "Hazardous" air quality. The map also has active fires plotted with flame icons.

August 19 at 7 PM: Air Quality Sensors and Active Fires. Pacific Northwest Smoke Cooperators

This high resolution MODIS satellite image shows the thick grey smoke over the Pacific Northwest. The image was taken around noon PDT, and it shows how the air in southeast Washington and the southern Idaho Panhandle was "cleaner" than central and northeast Washington.

MODIS Satellite Imagery: August 19 Noon PDT.

Places like Pullman and Lewiston not only experienced more sunshine on Sunday (Aug 19), but also got much hotter than places shrouded in smoke. The Pullman airport had a high temperature of 90 degrees on Sunday, and Lewiston topped out at 97 degrees. Spokane is only 70 miles from Pullman and was 13 degrees cooler with a high of 77 degrees.

By the evening, smoke spread into southeast Washington and the southern Idaho Panhandle. This animation from Pullman WA shows a wall of smoke arriving before sunset.

When will our smoke situation improve? North Idaho and much of eastern Washington should experience improved air quality by mid to late morning on Monday. The arrival of a cold front will produce gusty north/northeast winds. "Cleaner" air from central Canada combined with the mixing from 15 to 25 mph winds should push smoke toward Oregon and western Washington on Monday. The three images below is a smoke forecast model. The initial is the model smoke depiction for 5 PM Sunday, August 19th.

By 11 AM on Monday, increasing northeast winds should push the thickest smoke into Oregon and western Washington.

By 5 PM on Monday, the reds and pinks representing thick surface smoke should be pushed into western and central Oregon.