The US Olympic track and field trials were suspended on Sunday as oppressive heat sparked frightening scenes.
Temperatures reached 42 degrees Celsius at one stage in Oregon, with heptathlete Taliyah Brooks carted off the field in a wheelchair after collapsing.
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Fans were filing into the stadium for the headline races of the final day of the trials when the track announcer said action was being suspended due to extreme heat at around 3pm.
All spectators were asked to evacuate.
A USA Track and Field official said temperatures on the surface of the track exceeded 65 Celsius.
Brooks was in fourth place after five of the seven heptathlon events when she collapsed during warmups for the sixth event - the javelin.
She was initially listed as a "DNS" - did not start - but officials later said she had been granted a request to re-enter the javelin competition when the action resumed.
After that, she would join the last event - the 800 metres.
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Among those still waiting to secure spots in the Olympics were Noah Lyles in the men's 200, and Dalilah Muhammad and Sydney McLaughlin, who were set to face off in the women's 400 hurdles.
Earlier, JuVaughn Harrison won the high jump in soaring temperatures and humidity.
Third-place high jump finisher Shelby McEwen called the heat "mind-blowing."
"It's crazy. I wasn't expecting it to be this humid," he said.
"We just had to be mentally locked in, mentally prep ourselves for it, stay hydrated and go out and get the job done."
The men's 5000m took place at 10am because of the forecast, with Paul Chelimo fending off a pair of runners for a 0.19-second victory.
"Honestly," Chelimo said, "I wanted it a bit hotter."
A record heat wave settled in over the Pacific Northwest for the second day, with the temperature in Portland - two hours north on Interstate 5 - reaching an all-time record of 43C.
Fans were left gobsmacked that officials let things progress so far before suspending the action on Sunday.
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