Practice Two at the US GP was cancelled on Friday after a huge electrical storm saturated the Circuit of the Americas.
Treacherous weather had been forecast for the Texan state capital for Friday afternoon, with the area's weather system being affected by Hurricane Patricia, which is currently fast approaching Mexico's Pacific coast and is the strongest storm ever recorded in the region.
With dark clouds gathering over the Circuit of the Americas, the FIA announced the delay to P2 minutes before the session was due to start with lightning in the area potentially putting marshals in exposed areas around the track at risk.
With spectators and camera operators also advised to take cover from the elements, the heavens soon opened, saturating the undulating circuit within minutes. Claps of thunder were also heard.
Although the rain briefly eased after half an hour, conditions soon worsened again and at 3pm local time the FIA announced that the session had been cancelled, citing the inability for the medical helicopter to take off for the next two hours with no let-up predicted on the radars.
The torrid weather is expected to continue into Saturday, when Practice Three and Qualifying are scheduled to take place.
"I hope it's not like today, that's the only problem! You'd think here, no chance of rain at this time of year, but there you go," F1 commercial supremo Bernie Ecclestone told Sky Sports F1.
"I don't feel sorry for any of us [in F1], we're doing a job, I just feel sorry for the public who have come here to see some racing and are getting soaked."
Practice One had earlier taken place, but drivers were unable to sample dry-weather tyres after heavy overnight rain. The last two F1 Fridays in Japan and Russia have been rain affected, severely compromising teams and drivers' usual build-up to qualifying and the race.
Lewis Hamilton, who could clinch his third world title on Sunday, completed just four laps in P1 on the way to the fifth-fastest time and joked afterwards: "It's been a beautiful day... I love it when it rains! Just not on practice day!"
"It's kind of cool to watch, in many ways, but I feel terrible for all the fans who turned out today. I didn't complete many laps in the morning as the track was drying out and I wanted to save my tyres for the afternoon session - but in the end we didn't get to go out.
"I would actually have liked to, just to see what it would have been like in those conditions, but of course the safety of the marshals and everyone else has to come first."
The grim Saturday forecast raises the spectre that more sessions - and perhaps even qualifying - will be disrupted and Hamilton is now hoping the weekend isn't completely compromised.
"We've got very little information to work with now, so the rest of the weekend will be intense," he admitted. "But it's the same for everyone, so we'll just have to make sure we make the best job of it. Fingers crossed we can get out there tomorrow and on Sunday. If the rain really is going to be heavier tomorrow like they're saying then maybe I'll take the day off and go to the movies. But the main thing now is that we're able to have a race!