As wildfires burn across the Western U.S., the people in harm’s way are increasingly those least able to protect their homes from fire risks, evacuate safely or recover after a fire.

In a new study, we and a team of fellow wildfire scientists examined who lived within the perimeters of wildfires over the past two decades in Washington, Oregon and California – home to about 90% of Americans in the U.S. West exposed to wildfires over that period.

Overall, nearly half a million people in California, Oregon and Washington were exposed to wildfires at some point during the past 22 years. Alarmingly, about half the people exposed to wildfires in Washington and Oregon were considered socially vulnerable.

While the number of people exposed to fire rose overall, the number of socially vulnerable people exposed more than tripled between the first and second decades.

A variety of factors shape social vulnerability, including wealth, race, age, disability and fluency in the local language.

These factors can make it harder to take steps to protect homes from wildfire damage, evacuate safely and recover after a disaster. For example, low-income residents often can’t afford adequate insurance coverage that could help them rebuild their homes after a fire. And residents who don’t speak English may not hear about evacuation orders or know how to get assistance after a disaster.

We found that older adults in particular were disproportionately exposed to wildfires in all three states.

Physical difficulties and cognitive decline can hamper older adults’ ability to keep their properties clear of flammable materials, such as dry shrubs and grasses, and can slow their ability to evacuate in an emergency. The fire that destroyed the town of Paradise, California, in 2018 was a tragic example. Of the 85 victims, 68 were 65 years of age or older.

Poverty was another important factor in the exposure of people with high vulnerability to wildfires in Oregon and Washington.

The reasons that socially vulnerable people were increasingly exposed to wildfires varied by state.

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