A Beautiful Yet Grim Map Shows How Wildfire Smoke Spreads

We in the San Francisco Bay Area have been choking on smoke from dozens of huge blazes—which have burned over 1.4 million acres, or 2,200 square miles, so far—sparked by a freak system of thunderstorms two weeks ago. But we’re not alone: California’s firestorm is spewing so much smoke, it’s drifting clear across the country, falling out in small quantities on the East Coast and accumulating above the Atlantic Ocean.Scientists have been forecasting where this smoke will end up 48 hours ahead of time with an experimental model called HRRR-Smoke (pronounced her), from the National Oceanic and Atmospheric Administration. It spits out a beautiful yet troubling map of a country positively awash in wildfire haze. Open up the smoke map here, and I’ll walk you through the clever science behind it.HRRR-Smoke begins by parsing a stream of infrared satellite data, which looks for heat anomalies in the United States—fires that have erupted across the landscape. (On the menu on the left side of the map, click “Fire Detections” to see where blazes are burning in California.) The neat bit about HRRR is that it’s not relying on satellites to see exactly where the smoke is, just where these fires are. Instead, it relies on sophisticated weather models—changes in temperature, wind, water vapor, and precipitation—to project where the smoke will eventually end up.
Think about a weather model as being like 100 overlapping window screens, like the kind that keep bugs out of your house, stacked into the sky. All of those overlaps create thousands of crossover points at different levels throughout the stack. “At each one of those little intersections of those wires, we're solving these equations: How much change is there?” says Stan Benjamin, senior weather modeling scientist at NOAA Global Systems Laboratory and branch leader for development of HRRR. “It's lots of computations to be able to put all that together and see how all these different aspects of the atmosphere—and actually parts of the earth system—are affecting each other.”

A visualization of vertically integrated smoke spreading across the US. Red is high levels of smoke, blue is low levels.

Courtesy of NOAA
So if you’re looking at the HRRR-Smoke map, on that same left-hand menu, click on “Near Surface Smoke.” This gives you smoke concentrations at about 8 meters off the ground, which are indicated on a light-blue-to-purple color scale at top right on the map. As you might expect, California is currently covered in a smoky haze—purple and red is scary-bad, while light blue indicates fairly low concentrations, measured in micrograms per cubic meter of air. But if you zoom out to the entire US, you’ll see that smoke has traveled clear across the country, landing in New York. These are tiny amounts, to be sure, but they’re there.