A dangerous heatwave is set to scorch the western United States, with record temperatures possible in parts of the country.
Baking sun will see California's notoriously hot Death Valley reach as high as 54C (129F), not far off the world-record high of 57C (134F) recorded there exactly a century ago.
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A series of safety precautions are being put in place, with temporary cooling stations being set up for the homeless and elderly as airlines monitor the soaring temperatures to ensure it remains safe to fly.
In Las Vegas and Phoenix - where tigers at the city's zoo are being fed frozen fish snacks - the strong high-pressure system settling over the region is expected to see the mercury hit up to 48C (118F).
Temperatures are expected to be only slightly lower in Utah - marketed as having "the greatest snow on Earth" - parts of Wyoming and Idaho.
And cities in Washington state, which is better known for cool, rainy weather, should get into the mid-30s early next week.
In Albuquerque, New Mexico, the mercury hit 41C (105F) on Thursday afternoon, the hottest it has been in the state's most populous city in 19 years.
National Weather Service meteorologist Mark O'Malley said: "This is the hottest time of the year but the temperatures that we'll be looking at for Friday through Sunday, they'll be toward the top.
"We'll be at or above record levels in the Phoenix area and throughout a lot of the southwestern United States. It's going to be baking hot across much of the entire west."
Scientists say that the jet stream, the river of air that dictates weather patterns, has been more erratic in the past few years.
It is responsible for weather systems getting stuck, like the current heatwave. Scientists disagree on whether global warming is the cause of the jet stream's behaviour.