People up and down the Eastern Seaboard awoke to hazy skies Tuesday, with the culprit once again being wildfire smoke from Canada in what has been a historic and abnormally long-lasting season.

The smoke drifted as far as South Florida, compromising air quality in one of the few places in the eastern United States that had — until now — avoided it. Much of the peninsula observed code orange or code red air quality Tuesday morning, according to AirNow.gov, the air monitoring website run by the Environmental Protection Agency. Code orange signifies unhealthy levels of smoke pollution for sensitive groups, while code red is unhealthy for everyone.

Canada’s unprecedented fire season burns into fall

Both Orlando and Jacksonville observed code red levels, which extended as far south as Palm Beach County. Skies were even obscured in a milky haze into Miami and Homestead.

Lesser but still noticeable areas of smoke hovered over the northeast and Mid-Atlantic, the highest smoke concentrations near the coast and Interstate 95 corridor.

A long journey

Most of this smoke came from Canada’s west following the rapid expansion of firestorms during the last ten days of September. The smoke arrived in the eastern United States after a long, winding journey that resulted from complicated atmospheric steering currents.

Last week, a weather pattern known as an omega block became established over central North America, featuring a sprawling zone of high pressure. Low pressure flanked that high pressure zone to both the east and west.