The opening day of the WGC Match Play Championship has been halted after more than four centimetres of snow fell on the course.
Less than four hours of play took place at the course, in the Arizona desert before the flurry forced organisers to suspend play, eventually calling time on the opening day.
"I have never seen anything like that at a golf tournament," said McIlroy, top seed at the event. "I've seen snow on the course when I was a kid, but nothing like that on any of the tours. It was crazy."
Organisers have warned of a possible early frost that could delay action resuming today, although forecasters expect the snow to have cleared away overnight.
Second-round matches will also be started today, and completed tomorrow. Third-round matches will follow on Friday, and if those two rounds are completed at the time, the tournament will be back on schedule.
Lee Westwood was two up on Rafael Cabrera Bello after five when play stopped, while Justin Rose was two up at the turn on South Korean KJ Choi, although he had been four up after five.
Jamie Donaldson, who won the Abu Dhabi Championship last month, had to take a penalty drop after his opening drive and bogeyed five of the first seven holes to be three down to Thorbjorn Olesen, but Chris Wood, who won his first European Tour title a week later in Qatar, was level with Masters champion Bubba Watson after six.
Closest to winning was Sergio Garcia, whose first shot on his return will be a 12-foot putt to beat Thailand's Thongchai Jaidee on the 16th green.
The forecast was for the snow to have cleared away overnight, but there was the possibility of early frost and that would delay things further.
Jason Day, who would be enjoying warm summer temperatures if he were back home in Brisbane, said this was a first for him.
"This is crazy. I never played golf where you had to stop because of snow," Day said.
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