Smoke from the Canadian Wildfires blocking out the Sun on July 15, 2026. Credit: Getty Images.
On July 13, 2026, numerous wildfires ignited in the remote forests of northwestern Ontario, Canada, near the Minnesota border. By the following day, the fires had undergone explosive growth, producing dense smoke that spread rapidly into the midwestern and northeastern United States. NOAA satellites played a critical role in monitoring this event.
On the afternoon of July 13, 2026, NOAA’s GOES-19 satellite captured the ignition and explosive growth of many active wildfires in Minnesota and Ontario. The fires produced smoke plumes that caused hazy skies across eastern North America. Credit: ABI/GOES-19 satellite. Data are available from the NOAA Open Data Dissemination (NODD) program.
The smoke darkened skies and disrupted daily life in major Midwestern cities including Chicago, Cleveland, Detroit and Minneapolis, where millions of residents were placed under air quality alerts for several days. Washington D.C., Philadelphia and New York City also experienced degraded air quality on July 16 and 17.
The smoke brought harmful levels of fine particulate matter, which is a mixture of tiny solid and liquid particles that are generally 2.5 micrometers (µm) in diameter or smaller and are suspended in the air. These particles—which are 25 times smaller than the width of a human hair—can penetrate deep into the lungs and blood stream, making them a serious health concern, especially for individuals at greatest risk.
Animation of surface fine-particle pollution each hour from 13:00 to 21:00 UTC on July 17, 2026. Estimated observations made by NOAA’s Advanced Baseline Imager (ABI) on the GOES-East (GOES-19) satellite and the NASA TEMPO sensor. Credit: NOAA TEMPO aerosol products are generated using Level 1B data provided by Smithsonian Astrophysical Laboratory in partnership with NASA.
On the afternoon of July 14, the Visible Imaging Infrared Radiometer Suite (VIIRS) on board the NOAA-20 satellite captured the rapid increase in both the number and intensity of wildfires burning in northwestern Ontario, Canada.
VIIRS capturing the increase in the number and intensity of wildfires burning in northwestern Ontario, Canada, on July 14, 2026. VIIRS fire radiative power (FRP) is a measure of fire burning intensity. Credit: VIIRS/NOAA-20 satellite. Data are available from the NOAA Open Data Dissemination (NODD) program.
VIIRS imagery also tracked the dense, grayish-brown smoke as it circulated around the eastern edge of a persistent heat dome over the continental U.S. A heat dome is a strong high pressure system in the atmosphere that traps warm air near the ground. This causes sunny conditions and can lead to extremely high temperatures if they occur in the summer. The July 2026 heat dome helped trap smoke near the surface while funnelling it into the Great Lakes and Mid-Atlantic regions, where it lingered.
During smoke transport events like this one, NOAA satellites are a valuable resource for forecasters issuing air quality alerts to the public.
"Satellite resources like NOAA's AerosolWatch website enable air quality forecasters to easily track smoke transport in near real-time and provide earlier, more informed guidance on potential impacts to surface air quality," said James Boyle, Meteorologist at the Maryland Department of Environment.
The July 2026 smoke event had historic impacts across the eastern U.S. and Canada. Estimates derived from VIIRS observations via the NOAA-20 and NOAA-21 satellites indicate that approximately 120 million people experienced unhealthy air quality conditions during the worst day of the event at their location. That exceeds the estimated 110 million people affected during the June 2023 Canadian wildfire smoke transport event that occurred in the same region.
Graph showing the Millions (“M”) of people in the northeastern US and southeastern Canada exposed to the fine particle pollution, July 14–20, 2026. Credit: Numbers estimated from VIIRS on the NOAA-20 and NOAA-21 satellites and Gridded Population of the World, Center For International Earth Science Information Network (CIESIN), Columbia University.
This event also provided a unique opportunity for researchers studying wildfire smoke and its effects on public health.
“It's been a very eye-opening experience to work on the analysis of an event this extreme that I saw happen in real time,” said Jemma Przybocki, master's degree student and a fellow at the NOAA Educational Partnership Program (EPP) Center for Earth System Sciences and Remote Sensing Technologies II (CESSRST-II) at the University of Maryland Baltimore County. “Looking at the impacts of people exposed to bad air quality while also being able to look outside and see the haze really reiterates the importance of this type of work.”
Przybocki’s research focuses on estimating the value of ingesting near-real-time NOAA satellite fire detections and emissions into the National Weather Service (NWS) air quality forecasting models.
Having accurate, timely information is essential for helping communities prepare for and respond to wildfires and the smoke they produce, which can degrade air quality and reduce visibility hundreds of miles from the source. NOAA satellites continuously monitor wildfires, measure their intensity and track smoke emissions. This data then feeds into operational air quality forecast models developed by the NWS and U.S. Environmental Protection Agency (EPA).
“Without [this] data we would have had a difficult time grasping the severity of the incoming smoke plume until it was already occurring and being measured by surface based sensors, in which case there wouldn’t be any heads up.” -Minnesota Pollution Control Agency (MPCA) Communications Department.