Become a Member

Get access to more than 30 brands, premium video, exclusive content, events, mapping, and more.

Already have an account? Sign In

Become a Member

Get access to more than 30 brands, premium video, exclusive content, events, mapping, and more.

Already have an account? Sign In


Survive Wilderness Threats

Is It Safe to Hike in Wildfire Smoke?

With blazes blanketing much of the western US, we sourced some expert tips for staying safe on the trail.

Heading out the door? Read this article on the new Outside+ app available now on iOS devices for members! Download the app.

If you’ve been hiking in the western US this summer, odds are that you’ve seen the smoke from this season’s super-size wildfires. Mother Nature has been making up for years of human-driven fire suppression, and some officials say this could be the new normal for the foreseeable future. And for smoke-sensitive backpackers, that’s a bummer.

“Wildfires are increasing in magnitude, frequency and duration,” says Ann Logan, Deputy Air Pollution Control Officer for Great Basin Unified Air Pollution Control District. “Large fires can disperse smoke hundreds of miles, so the fire may not be in the area you are going but there still can be significant smoke impacts.”

Go hiking in thick smoke, and you could find yourself paying the price. “Wildfire smoke contains very fine particles that penetrate deep into the lungs,” Logan says. “Inhaling this fine particulate pollution can cause a variety of health effects and problems.” Smoke impacts can range from very mild (sore throat, running nose, watery eyes) to more extreme (shortness of breath, trouble breathing, chest pain) and can be difficult to spot. Some people seem impervious to the effects of smoke while others have serious problems, and it can be difficult to predict who will fall into either group.

According to Mono County Public Health Officer Dr. Thomas Boo, “the most common, potentially serious effects, will be related to inflammation of the lungs, including coughing, wheezing and shortness of breath. Less commonly, short-term exposure to particulate pollution occasionally triggers heart problems in people at risk.”

Kids, older people, and folks with preexisting health conditions should take special consideration before heading out into the smoke, as they’re more likely to experience negative effects.

“Children have more lung tissue for their body size than adults so the exposure to air pollution is proportionally higher,” says Dr. Boo. On the flip side, Dr. Boo says, kids are less susceptible to the cardiac effects because heart problems from smoke generally occur in people with heart problems

It’s hard to draw firm conclusions about smoke’s effect on hikers, because much of the conjecture about it is drawn from studies done on urban smog. But hiking increases exposure to air pollutants around us, so choosing to hike in smoky conditions should be a choice based on personal experience.

“Any type of physical exertion that causes us to breath faster and deeper dramatically increases the amount of air, and the pollutants in it, going into our lungs,” Dr. Boo says. “Greater lung exposure to particulate pollution increases the risk of harmful effects. However, I doubt that there are measurable long-term effects from occasionally hiking in wildfire smoke.”

How to Protect Yourself from Smoke

There are steps you can take to protect yourself, starting by checking the air quality before you head out the door. Good resources include, which provides air quality conditions for the entire United States, as well as your own state or local air quality reports. Keep in mind that smoke levels can change rapidly.

Already in the backcountry? You can estimate the smoke levels by looking at them. Follow Logan’s instructions:

1. To use visibility to evaluate air quality, you will be determining the limit of visual range by looking at landmarks, such as mountains, at known distances. The visible range is the point at which the landmark totally disappears. It must be daylight and you should be facing away from the sun.

2. Pick out several dark-colored landmarks at different distances. (Use a map.) If you see more than 10 miles the air quality is good, and you should watch for changing conditions. If you cannot see for more than 5 miles, the air quality is unhealthy and it’s a good idea to minimize or avoid outdoor activity. If you cannot see more than 1 mile, the air quality is hazardous.

3. No matter the visibility, listen to what your body’s telling you. If it feels bad to breathe, turn around.

How to Pack for Backcountry Skiing

Get to know the winter safety gear you need in your pack.