 A heat wave affecting millions of Americans with new record temperatures expected. A dangerous heat wave is once again scorching our nation's coast. Right now, more than 130 million people are under some type of heat alert. On the east coast, they stretch from upstate New York all the way down to South Florida. And out west, Death Valley, Las Vegas, and parts of Arizona could break all-time heat records. Temps in those places are forecast to soar above 110 degrees.