USA: Unusually bad wildfires have been blazing in the Western United States, leaving areas across Oregon, Washington, Montana, and Wyoming choking on harmful levels of smoke and shrouded in a cloudy haze.
Fire officials anticipate some relief this week as a weather system is expected to bring rain to some of the smoldering states. But the fires will also continue to burn through dry woodlands.
“We’re expecting another day or two of warm conditions that could keep the fires a little bit active, particularly across the Northwest and the Rockies, and also some breezy conditions in Montana that are pushing fires around,” said Ed Delgado, the national program manager for predictive services at the National Interagency Fire Center.
On Wednesday, NIFC was reporting 62 large fires across nine Western states that had already taken about 1.6 million acres. And 2017 is on track to be one of the worst years for wildfires in the US on record, with a total of 8.1 million acres burned as of September 13 — already well above the annual to-date average of 6 million acres for the past decade.
For residents of some areas of California, Washington, Oregon, Wyoming, Colorado, Idaho, Nevada, Utah and Montana, the worst threat from the fires is lingering poor air quality that may take up to a week to disperse. You can use this map to zoom in on which towns have it worst.
The Environmental Protection Agency measures the harm from wildfires with its Air Quality Index, as shown here in this live map.
The math is a little convoluted, but the index allows regulators to make apples-to-apples comparisons of health risks across different pollutants like ozone and sulfur dioxide.
The six categories for the Air Quality Index range from “good” (“It’s a great day to be outside.”) to “hazardous” (“Avoid all physical activity outdoors.”). As you can see, air in some parts of Montana reached that worst-case, “hazardous” level during some of the more intense wildfires last week. Here’s the map from September 6:
Unfortunately, smoke from wildfires poses a threat even in small quantities, and can cause harm even to people hundreds of miles away from the nearest flames.
Wildfires can loft bits of dust and carbon into the jet stream, but health hazards emerge when the local weather conditions bring these particles back down to ground level, which is why specific local air quality monitoring and forecasts are so important.
The town of Seeley Lake, Montana, about 50 miles from Missoula, suffered some of the highest pollution levels as blazes raged.
Bordered by the Swan and Mission mountain ranges, Seeley Lake’s geography traps dirty air over the town’s 1,600 residents.
The smallest particles are the biggest concern.
EPA regulates PM2.5, which refers to particles with a diameter of 2.5 microns or less. Wildfires directly create these particles as they torch plains and forests.
“Generally, we think that the smaller it is, the more likely it is to make you sick,” said Jia Coco Liu, a postdoctoral researcher studying air quality after disasters at Johns Hopkins University.
These particles penetrate deep into lungs causing inflammation, asthma attacks, and over the long-term, cancer.
Even in tiny concentrations, measured in micrograms per cubic meter, particulates can increase visits to the emergency room, especially for the elderly and people with chronic breathing problems.
“My research shows that when pollution is very high, over 37 [micrograms per cubic meter], we start to see health consequences,” Liu said.
Even on September 12, the Seeley Lake air monitoring station was reporting an off-the-charts spike in air pollution and an average particulate count of 214.6 micrograms per cubic meter over 24 hours.
Officials don’t have many options to help people get fresh air under smoke and haze. “Other than staying indoors, it’s pretty hard to do, because you can’t stop breathing,” Liu said.
Overall, this fire season is far worse than officials expected. “We had a very wet winter and spring, but that was pretty much erased in July when we had a very strong heat wave in the West that dried this out very, very quickly,” Delgado said.
As average temperatures continue to rise due to climate change, health officials are bracing for more wildfires scorching wider swaths of Western lands, leading to more coughing, wheezing, heart attacks, and deaths.
But on Tuesday fire officials had at least some good news to share for the regions blanketed by smoke: Almost half of ongoing wildfires didn’t gain any ground on Monday.
“Basically, it’s late in the year, so generally we’re in the wind-down mode,” Delgado added.