Northern California wildfires threatening thousands of homes

The River Fire burns near Salinas, Calif., Wednesday, Aug. 19, 2020. (AP Photo/Nic Coury)

A CalFire crew from Coulterville takes a break while fighting the River Fire near Salinas, Calif., Wednesday, Aug. 19, 2020. (AP Photo/Nic Coury)

Fire crews maintain a backburn to control the River Fire near the Las Palmas neighborhood in Salinas, Calif., Wednesday, Aug. 19, 2020. (AP Photo/Nic Coury)

Fire crews maintain a backburn to control the River Fire near the Las Palmas neighborhood in Salinas, Calif., Wednesday, Aug. 19, 2020. (AP Photo/Nic Coury)

Flames from the LNU Lightning Complex fires jump Interstate 80 in Vacaville, Calif., Wednesday, Aug. 19, 2020. The highway was closed in both directions shortly afterward. Fire crews across the region scrambled to contain dozens of wildfires sparked by lightning strikes as a statewide heat wave continues. (AP Photo/Noah Berger)

Flames from the LNU Lightning Complex fires consume a home in Vacaville, Calif., Wednesday, Aug. 19, 2020. Fire crews across the region scrambled to contain dozens of wildfires sparked by lightning strikes as a statewide heat wave continues. (AP Photo/Noah Berger)

Flames from the LNU Lightning Complex fires consume a home in Vacaville, Calif., Wednesday, Aug. 19, 2020. Fire crews across the region scrambled to contain dozens of wildfires sparked by lightning strikes as a statewide heat wave continues. (AP Photo/Noah Berger)

Smoke from California wildfires up to 200 miles away blankets a residential neighborhood in Sparks, Nev., Wednesday, Aug. 19, 2020. Local schools canceled all outdoor activities as the air quality index approached the "very unhealthy" category for the general population Wednesday afternoon. (AP Photo/Scott Sonner)

Dense smoke from California wildfires up to 200 miles away obscures the view of traffic traveling on Interstate 80, looking west in Sparks, Nev., Wednesday, Aug. 19, 2020. Local schools canceled all outdoor activities as the air quality index approached the "very unhealthy" category for the general population Wednesday afternoon. (AP Photo/Scott Sonner)

Flames from the LNU Lightning Complex fires jump Interstate 80 in Vacaville, Calif., Wednesday, Aug. 19, 2020. The highway was closed in both directions shortly afterward. Fire crews across the region scrambled to contain dozens of wildfires sparked by lightning strikes as a statewide heat wave continues. (AP Photo/Noah Berger)

Flames from the LNU Lightning Complex fires jump Interstate 80 in Vacaville, Calif., Wednesday, Aug. 19, 2020. The highway was closed in both directions shortly afterward. Fire crews across the region scrambled to contain dozens of wildfires sparked by lightning strikes as a statewide heat wave continues. (AP Photo/Noah Berger)

Firefighter David Widaman directs water onto a tree that had exploded in flame as a fire crew defends a house northwest of Santa Cruz, Calif., Wednesday Aug. 19, 2020. (Shmuel Thaler/The Santa Cruz Sentinel via AP)