Nuclear Winter test fire: fire crews rest while monitoring the brown smoke rising from smoldering brush fires, deliberately started to study the potential climatic effects of a nuclear war. The nuclear winter theory predicts that smoke from fires burning after a nuclear war would block sunlight, causing a rapid drop in temperature that would trigger serious ecological disturbance. The test burn took place in December 1986 on 500 acres of brush in Lodi Canyon, Los Angeles. Dripping napalm from a helicopter ignited the fire. Ground-based temperature sensors were used to study soil erosion. Various airborne experiments included smoke sampling & high-altitude infrared imaging from a converted U-2 spy plane.