ESPN rounds up all the reaction from up and down the paddock after Friday practice at the Circuit of the Americas.
Lewis Hamilton: "It's been a beautiful day... I love it when it rains! Just not on practice day! The weather has just been unbelievable. I don't think I've ever seen rain like this. 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. I was surprised by how much grip there was on the intermediates in the few laps I did get, though.
"The track surface varies massively between circuits and I think this is the most grip I can remember having on those tyres. It really did feel very good, so we'll have a lot of fun if it's like that in the race. There's not a lot you can do in these situations. You want to be out there but you just have to sit and try to enjoy some down time, then make sure you're fresh and ready to go the next day. We've got very little information to work with now, so the rest of the weekend will be intense. 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!"
Nico Rosberg: "For me it wasn't a bad day. I did my homework in the morning session, had a good quick lap and also tried a bit of work on setup. But it's a shame for the spectators out there. They pay a lot of money to be here and didn't see a single car driving in the afternoon. So let's see what tomorrow brings - but the forecast is not good..."
Paddy Lowe, executive director (technical): "Intermediate conditions at the beginning of P1 meant that we were able to do some limited running with both drivers to get a feel for the balance of the car in the wet and also to perform a couple of practice starts. The pace seemed to be encouraging from what we could see. Later in the session, however, the circuit was drying quite significantly, so putting in more laps would have damaged the tyres very quickly. Since we only have the one set of intermediates for the whole of Friday, we therefore chose to save them for P2. Unfortunately, the whole of the afternoon session was cancelled, so that was perhaps an opportunity lost. The forecast suggests more of the same for tomorrow but we hope for the sake of the spectators that we will be able to run in qualifying."
Daniel Ricciardo: "This weather is beautiful for the farmers. They need some water on their dry farms. It's obviously a shame for us and the fans. I think on days like this you feel more sorry for the fans, because especially on the Friday, a lot of people take time off work to come and see us, so I feel for them. But we'll definitely race. The forecast for tomorrow looks quite bad already but if we have to qualify and race on Sunday then that's what we'll do - if it's like this tomorrow maybe we can go downtown and listen to music all day! The laps we did this morning were quite good. We know that in these conditions we are strong. With mixed conditions on Sunday we should be okay. I like this circuit and it's one of my favourites. The car has been a lot better straight away in the last few races, so even if it's dry on Sunday I think we'll be able to attack."
Daniil Kvyat: "There was not so much to do out there today but we did a couple of laps in FP1 which was good for me to get on the track for a bit. But in FP2 there was obviously so much rain that we couldn't even drive. We had some fun in the garage this afternoon because we didn't get out at all, it was good to spend some time with the guys but obviously we would like to drive! If tomorrow is the same I guess I'll bring my laptop, some movies, some magazines and a book and then we'll see! The forecast is showing a chance of this sort of weather for a while so obviously we have to take every lap we can. It's important to make the most out of what we did this morning and we also have to be ready in the event that everything is cancelled up until the race itself. This kind of weekend usually always makes the race more interesting."
Valtteri Bottas: We had a bit of running this morning, so with both cars we were trying some different setup changes to learn more about the wet weather and our performance. We did struggle today with front tyre graining. It would have been nice to go out again and try something different. We managed to get into the top 10, which is slightly better than we've seen, but we still have a lot of work to do in the wet. We can't change the weather and it's the same for everyone so we'll take it as it comes. Hopefully it's dry for Sunday, that's the main thing.
Felipe Massa: "Not a lot happened today. We did a few laps on the wet tyre in the first session, which was ok to drive and gave us some ideas for the setup. We didn't run in the second session as it was raining a lot. We just need to wait to see if it will be possible to drive tomorrow. It's not nice to see the weather like this, so I hope it gets better for everyone."
Rob Smedley, head of performance engineering: "We've missed a complete session, we didn't even start FP2 before it was cancelled due to the weather. That's a great deal of learning that we've missed out on, but it's the same for everybody. FP1 was also a bit of a washout with us just getting a little bit of work done on the intermediate tyre. There were some interesting results coming up, but learning for this weekend has been pretty minimal. We just have to see what the weather brings tomorrow and be ready with our different contingency plans."
Sebastian Vettel: "I have witnessed something like this already - yes. We had a year in Canada where the race was held for a long time due to rain; and we had a year in Japan, where we had to cancel Qualifying on Saturday and do it on Sunday. It is a shame, especially for the people who came to see us this weekend here at the circuit. But there is not much we can do. We have to remain calm and get prepared for tomorrow as a normal day. Today we obviously didn't learn a lot, then we see from the conditions what the day brings. Everybody is in the same situation."
Kimi Raikkonen: "We cannot take very much from today's free practice. This morning, we only did three timed laps because we wanted to save intermediate tires for the second session. We don't have many sets of tires for the rain conditions and if we still expect more rain it's better to keep them. It's a difficult situation but it's the same for everybody. At the moment we are just guessing, tomorrow we'll see how it is and then what comes after that if we can't drive. With this weather conditions there's more gamble and more chances for odd races, it can go all for you or against you. It's a shame for everybody, the spectators can't see anything and we can't drive because of the conditions. Hopefully we get the proper conditions at least on Sunday and we can do qualifying and race. We'll try to make the right decisions. I'm sure we have the speed to recover at the start."
Fernando Alonso: "It's a pity we couldn't get any running under our belts this afternoon. We had a productive morning session, running through some power unit and aero evaluations. There's definitely progress being made, and it would've been nice to have further validated those changes in FP2. This afternoon, the rain was just too heavy for us to run safely. I can't remember the last time I saw weather like that - it was unbelievable. In these situations, the highest priority is to keep the fans and competitors safe - so we made the right decision today."
Jenson Button: "It's always disappointing to have to cancel a session, but I think this afternoon's decision was entirely correct - the track was never in a sufficiently safe condition to enable us to run, and the loss of daylight meant it wasn't possible to prolong the session either. "That's a real pity for all the fans who came to the track today. The main thing is that people stayed safe - particularly with the proximity of the lightning today. It's always difficult when these things happen. As racing drivers, we try our best, but weren't able to do anything today. Although the forecast doesn't necessarily predict it, here's hoping for a better day tomorrow."
Eric Boullier, racing director: "There are sometimes days when the fans question teams' reasons not to run in wet weather. Today, however, I think it was apparent to everyone that the conditions were clearly impossible; much of the track was underwater, there were puddles everywhere, huge cloaks of mist shrouded large parts of the circuit, track workers were at risk of being struck by lightning, and, eventually, the medical helicopter was unable to run safely. Non, this afternoon, we could not run.
"Nonetheless, I feel for the fans who had visited today in the hope of seeing some Formula 1 action. I hope they understand the reasons why we couldn't run today, but hopefully we'll be able to put on a fantastic show for them during the rest of the weekend."
Yasuhisa Arai, Honda R&D senior managing officer - chief officer of motorsport: Our first grand prix in Austin started in very wet conditions. Obviously, we had hoped for more running time to achieve both power unit and aero update settings, however the heavy rain in the afternoon meant that it was necessary to cancel FP2. It was the correct decision for the safety of the fans and the teams.
"Thankfully, we were able to get some mileage under belts in the morning FP1 session, by running both cars in the semi-dry conditions. This also gave us more fundamental data on Fernando's updated ICE. Tomorrow looks to be another wet day, so tonight's data analysis will be very important for the team."
Nico Hulkenberg: "When the track conditions are so poor, there is little value in running. We did a few laps but the grip was nowhere and there was no way we could collect any usable data. Tomorrow is likely to be very wet as well so there is a chance we will get to the race with very little information about the tyres and the set-up. If this is the case, it will be all about learning as we go, adapting quickly and making decisions based on the information we have. We have done that before when the circumstances were similar and I'm confident we can be competitive regardless of the amount of preparation."
Sergio Perez: "Since the start of the first session this morning, the conditions have not been ideal, so we have only been able to complete a handful of laps. It's a real shame for all the fans who came to see the action. At this moment, however, my main worry is for my country. Mexico is being hit by the largest hurricane in its history and all my thoughts are with my people. I am praying for everyone to be safe. We are not expecting the weather to improve tomorrow so we are looking at very limited running, but hopefully by Sunday there will be an improvement and we'll be able to produce a great race for the fans. Mixed conditions can be an opportunity for a big result: we just need to keep focused, calm and do what we have to do."
Vijay Mallya, team owner and managing director: "It is never ideal to have sessions affected by the weather in such a significant manner. Of course, the safety of everyone involved in our sport has to be considered, be it drivers, marshals or spectators, so it makes perfect sense for the second practice session to be cancelled. With more rain seemingly on the radar for tomorrow, we will need to analyse the data we have managed to gather in the limited running in FP1 and decide the best way forward. We have seen in the last two races that we can be very competitive even with limited running before the race and I'm confident we can do so once again this weekend. It's the same situation for everyone up and down the grid, so we will need to prepare best we can ahead of qualifying and aim to claim our spots in the top ten."
Max Verstappen: "It was good to be back driving here in Austin again. It's a shame about the weather, as we were not able to complete many laps because of the rain. But the car was performing well in the wet, so we can be happy about that. You never want this much rain on a Friday, especially during my rookie year when the most important is to get as much mileage under your belt as possible, but we just have to deal with it."
Carlos Sainz: "We were only able to do three complete laps today because of the weather conditions. It's a shame, because this is a new track for me so it's important to get as much mileage as possible out there - but ending up P4 in FP1 is a good achievement. The car felt good in the wet and this gave me confidence. The fact that we didn't get any running in FP2 is not ideal, but we just need to wait and see if the rain stops tomorrow."
Phil Charles, chief race engineer: "It's disappointing that the weather has curtailed our running today. Having two young drivers, we were hoping to get lots of mileage in. Having said that, both Carlos and Max got some Inter laps in during FP1 after waiting a little bit for suitable weather conditions, and they did fine. I was pleased to see that their experience has grown to the point now where they both radioed in to come through the pits and do a flap adjust to tweak the balance to their liking. We are now looking forward to the rest of the weekend, where there is more rain forecast; in particular very heavy rain tomorrow. Despite the limited running we have done we have collected some information on the inter tyre performance and wear, so there's some interesting stuff for us to work on tonight to ensure race performance will be ok."
Romain Grosjean: "It didn't feel too bad out on track, especially with a fresh set of intermediates, however there wasn't much point in completing a lot of laps. The main thing I learnt was that when they say everything is bigger in Texas they mean it; especially with the rain!"
Pastor Maldonado: "I only managed an installation lap today so it wasn't the busiest day I've ever had at the track. We had a gearbox issue as soon as I was on track so I didn't even set a lap time. The rain was pretty impressive, but it's not what you want when you want to be refining the set-up of the car and collecting data. It's the same for everyone and we'll be busy tomorrow if the weather improves."
Alan Permane, trackside operations director: "Today was a washout. Pastor suffered from a minor gearbox issue which we have fixed and Romain only completed a handful of laps in FP1. For FP2 we watched the skies and listened to the rain. We're closely monitoring the weather forecasts for the rest of the weekend."
Will Stevens: "It's always frustrating to have to spend practically a whole day of running confined to the garage, particularly when this is a new circuit for me and I really want to get stuck into the programme. Fingers crossed we'll have a few dry moments tomorrow."
Alexander Rossi: "After all the promotional activity this past week, I was looking forward to finally getting stuck into on the racing side of things. But the weather definitely had other ideas and instead it's been a little frustrating standing on the sidelines with little opportunity for running. It doesn't look like it will get any better tomorrow either! 11 laps wasn't quite what I was hoping for today, but we're all in the same boat. Literally!"
John Booth, team principal: "There isn't much to report from the opening day of running here; mainly on the basis that we didn't do very much! Alex's much-vaunted home soil debut was much briefer than perhaps he and the crowds had hoped for and I'm sure he and Will are equally frustrated to have such a fruitless Friday. I would say we're hoping for better conditions tomorrow, but judging by the forecast I think we're in for more of the same. Hopefully, it will all come good on Sunday."
No reaction from either Sauber driver post-session
The team's post-Friday press release said: "It was an unusual Friday for the United States Grand Prix in Austin. During the first practice session test and reserve driver Raffaele Marciello was back in the cockpit for the fourth and last time this season - after Malaysia, Spain and the UK. Austin rookies Marciello and Marcus Ericsson were able to cover some mileage on the Circuit of the Americas in both wet and damp conditions. Raffaele Marciello completed 19 laps, whereas Marcus Ercisson put in 18 laps mainly on intermediates. In the afternoon it was not possible to run FP2 due to the severe weather conditions. Therefore, Felipe Nasr was not able to put in any laps today."
Paul Hembery, Pirelli motorsport director: "We saw another wet Friday, which ultimately led to the cancellation of FP2: something we haven't experienced yet and a factor that certainly puts the teams on the back foot going into tomorrow. However, it's obviously just one of those weather events that is exceptional and under nobody's control. From what we hear, more rain is expected so we'll just have to wait and see what happens.
"In the morning, the teams were able to complete the usual long run preparations, as well as looking at crossover points between wet and intermediate, which could be important for the race. Interacting with fans has always been very important to us, so as we all hope for more action tomorrow, we're very pleased to launch our latest social media campaign today that allows people to get involved by voting for which colour they would like our new 'ultrasoft' tyre to be. We're looking forward to hearing everybody's feedback."