The wildfire in Yarnell, Ariz., last June destroyed homes and killed 19 firefighters. Experts say expansion into wildfire-prone areas has created new challenges for firefighters.
Ripening fruit in a grove in Plant City, Fla., this month. Florida citrus growers are worried about citrus greening, which causes bacteria to grow on the leaf and fruit, eventually killing the tree.
Workers in Oakland, Calif., check the damage to Interstate 880 on Oct. 19, 1989; this portion of the freeway had collapsed during the Loma Prieta earthquake two days earlier.