Nightly News | June 28, 2013
>>> good evening. i'm lester holt in tonight for brian.
>>> this will be a weekend to remember. extreme heat gripping parts of the west tonight. expected to send mercury close to 120 degrees in cities like las vegas and phoenix and even threatening to ground some flights. parts of california, nevada, and arizona are under heat alerts as officials warn people of risks that include heat stroke and even burns from searing sidewalks. and parts of the east dealing with severe storms and heavy rain that caused flash floods in upstate new york . we've got it all covered, beginning with gabe gutierrez in los angeles .
>> reporter: extreme heat warnings in effect now in five states. the west is baking.
>> extremely hot.
>> reporter: in los angeles , elderly are packing cooling centers. they feel safe here.
>> i have no one to help me. i live alone.
>> reporter: heat-related power outages snarled traffic. ac repair people are strug tloing keep up. and at this dry cleaner , coolers full of water for his employees.
>> very uncomfortable. when the elements get this high, really not too much you can do.
>> reporter: so stifling, that for one, even sin city is sweating. las vegas could break a record high of 117 degrees.
>> we don't want anybody to pass out. we don't want anybody to get heat exhaustion .
>> reporter: death valley forecast to reach 129 degrees this weekend, just shy of a world record . and alaska -- yes, alaska -- is running out of fans and air conditioners .
>> this is the last of what i have.
>> reporter: the western u.s. is no stranger to hot weather . in phoenix, forget dry. they are calling this a fry heat. rush on to protect zoo animals. what's behind this potentially historic heat wave ? meteorologists blame an unusually strong area of high pressure , but nasa's top scientist says there is something else.
>> the frequency and intensity of the heat waves are affected by the fact that the globe is getting warmer due to the buildup of greenhouse gases .
>> reporter: officials are urging millions of people to drink water and be careful outdoors. a wave of caution during a blistering start to summer. here in california, the height of the tourist season , officials worry that a spark from a cigarette in this heat could lead to more forest fires , lester.
>> all right, gabe. thank you.