The haze hanging over McHenry County doesn’t consist of clouds, but a layer of smoke and ash blowing in from a forest fire in Canada, National Weather Service meteorologists said.
Relatively strong winds out of the northwest have carried the smoke from Saskatchewan into Wisconsin, northern Illinois and Indiana, said meteorologist Andrew Krein, who is based at the agency’s Romeoville office. The result is a layer of smoke and ash hanging 9,000 feet above ground level, he said.
“It’s because we’re right down stream,” Krein said.
As with a volcanic eruption, the wind carried wood ash thousands of miles from the original site, Krein said.
“It’s not uncommon, really,” Krein said. “It’s usually not as thick as we’re seeing right now.”
Another effect of the smoke has been a red-tinted sun. Krein explained the sun’s color is a result of ash particles scattering wavelengths of light. The red hue will diminish as the sun gets higher in the sky, but they will return as the sun sets, Krein said.
If the northwest winds continue, the haze will hover over the area until Wednesday afternoon, when the wind shifts to out of the west, he said.
The smoke shouldn’t affect people, Krein said, because of its altitude.
The only other potential effect could be temperatures reaching a couple degrees lower than predicted. Meteorologists had forecast highs in the mid-80s.