Currently, Detroit, Chicago and Minneapolis have the the sickest look in the world, except for Dubai. Canadian wildfires are belching smoke billowing south, blanketing the Midwest in toxic haze, just as they did earlier this month along the east coast. Seventeen States—with almost a third of the population of the United States – are under air quality alert.
The animation above gives you an idea of the scale and gravity of what is unfolding. This is an experimental model called HRRR-Smoke (High-Resolution Rapid Refresh), produced by the National Oceanic and Atmospheric Administration (NOAA), and it has become a essential tool for meteorologists and atmospheric scientists. (You can play with the map here.)
It’s a forecast of how the smoke could move today, showing how it’s swirling around not just in the Midwest, but again on the East Coast, and even in the South. The model predicts the smoke could continue to billow as far south as Georgia through the end of the day. (This chart forecasts hours ahead, not days.) The warmer the color, the higher the concentration of smoke in the air.
Specifically, this animation shows “Near Surface Smoke,” or concentrations about 26 feet above the ground. That’s what Midwesterners need worry about breathing. Smoke from forest fires is a cocktail of really nasty stuff, including charred particles, such as plants and dirt, which can penetrate deep into the lungs and irritate the airways. It’s also loaded with toxic chemicals, like benzene and formaldehyde, and can even develop new harmful agents as it moves through the atmosphere, like ozone. People with asthma are particularly vulnerable to this toxic gas which inflames the airways.
Interestingly, the HRRR model is not based on direct smoke measurement. Instead, it uses infrared satellite data, which identifies wildfires and assesses their severity. It then uses weather models, which take temperature and wind into account, to predict where the resulting smoke is heading.
The animation above shows a different measurement: “Vertically Integrated Smoke”. This models a column of air 15.5 miles high. It is the smoke that you can see in the sky, as opposed to the smoke that is hazardous to health at ground level.
While the smoke is a public health emergency for residents of the Midwest and East Coast, it’s also a scientific opportunity. Researchers can use HRRR to model where the smoke is going, and then use measurements during an event like this to improve that modeling. “From a scientific perspective, we think the HRRR smoke model does the right thing,” says Stan Benjamin, senior weather modeling scientist at NOAA Global Systems Laboratory and branch lead for HRRR development. “We have people in our lab working on using surface smoke measurements, as well as satellite imagery, to refine the initial conditions of the HRRR model.”
THE The National Weather Service predicts that the smoky conditions will continue into tomorrow, but the source of all that smoke shows no signs of letting up. Canada suffers from a unprecedented wildfire season, and the fingerprints of climate change are everywhere. The warmer the world gets, the easier it is for the atmosphere to suck moisture from vegetation, turning vast landscapes into tinder. All it takes is a discarded cigarette butt or a thunderbolt, which multiply increasingly common in the north– to start a fire that is getting out of control.
All that to say, keep the HRRR card handy. Smoke from forest fires is not just a problem for western states more, but for all of North America.