A punishing heat wave hits the West and Southwest U.S.
A heat wave that's expected to peak this weekend kicked off with record high temperatures and put one-third of Americans under heat alerts.
A heat wave is ramping up across the Western United States this weekend, when millions of Americans are expected to see record-breaking temperatures.
With heat alerts extending well into the week ahead, West Coast and Southwest residents may not see relief for days.
About were under excessive heat warnings, watches or advisories over the weekend, according to the National Weather Service, after a persistent hovering over Texas expanded to California, Nevada and Arizona.
