Millions of Americans have been sweltering under a heat wave that has brought triple-digit temperatures to parts of the South.
The scorching temperatures are being brought on by a "heat dome," which is created when a ridge of high pressure builds over an area, trapping air inside as temperatures warm — often to uncomfortable or even dangerous levels.
As Americans face hotter and hotter temperatures, officials are urging people to take safety precautions. The medical examiner in Webb County, Texas, reported Wednesday that nine people had died in eight days due to heat-related illnesses.
