In early summer, a day laborer laying irrigation lines at a plant nursery just south of Portland, Ore., collapsed to the ground and died. His official cause of death was declared “heat related.”

It was 104 degrees out — several days into a brutal heat wave whose like has become increasingly commonplace in many parts of the country. Mussels and clams baked in their shells along the Washington coast. Record temperatures and fierce winds fueled one of the largest wildfires in the United States.

Drought, megafires and heat waves are descending on the Pacific Northwest as the effects of climate change alter the landscape. They have forced farm owners, fieldworkers and state regulators to navigate newly extreme conditions.