Millions of people from southwestern Oregon through California, parts of Arizona and western Nevada will be under excessive heat warnings Tuesday through Friday.
The highest temperatures are expected in Furnace Creek in Death Valley National Park, where temperatures could reach 120 degrees this week. Meanwhile, in southern California's Palm Springs area and the Coachella Valley, afternoon highs could hit 118 degrees.
Federal forecasters said major cities including Los Angeles, Phoenix, Las Vegas and Portland, Oregon, were expected to surpass 100 degrees, according to the weather service. Los Angeles Mayor Karen Bass said that emergency personnel have begun preparing for the heat wave and that authorities are setting up cooling centers around the city.