Millions in U.S. and Europe face extreme heat as wildfires break out

Brutal and dangerous temperatures are being felt from California to Massachusetts, with more than 120 million Americans under excessive heat warnings or advisories. The National Weather Service said that more than 60 new record highs will be set across 20 states by the end of the week. 

As temperatures soared into the triple digits, Hoover Dam experienced a major power scare when a transformer explosion sent smoke billowing. The dam supplies power to California, Nevada and Arizona. 

West of Dallas, an intense heat-fueled wildfire burned a number of homes as temperatures reached 111 degrees. The fire was about 10% contained with 4,000 acres burned as of Tuesday evening, according to officials.