At least 23 people have died and 3,500 structures have burned in the wildfires sweeping across Northern California; an estimated 170,000 acres have burned so far and authorities have ordered evacuations in a number of towns.
To get a sense of the scope of what’s happening there, I’m joined by Don Falk. He's a professor in the School of Natural Resources and the Environment at the University of Arizona, and studies fire history and ecology.
