More than 21 million Americans have lived within three miles of a large wildfire.

And almost 600,000 of them found themselves inside the firelines. According to new research, over the last 20 years, the number of people directly exposed to wildfires has doubled and the reasons why may surprise you.

Moji Sadegh is an Associate Professor of Civil Engineering at Boise State University and he joined Idaho Matters to talk more about this research.