More than 30 million Americans are under warnings as 'heat dome' bears down on West Coast and Las Vegas airport 'grounds flights' amid 117F temps The heat wave hitting the West Coast this weekend is the third to hit the region this summer In late June, the Pacific Northwest suffered under a 'heat dome' that led to about 200 deaths in Oregon and Washington Now, the same atmospheric effect is blanketing California and nearby states in heat through the weekend Flights were reportedly cancelled after McCarren International Airport in Las Vegas recorded a high temperature of 117F on Friday As the extreme heat conditions continue, passengers may face flight delays at airports in the Southwest as planes can have trouble taking off in extreme heat