Lewis Hamilton managed to brave treacherous track conditions at the Circuit of The Americas on Saturday morning to top the timesheets in final practice for the United States Grand Prix.
Heavy rain onset by Hurricane Patricia and local flood warnings cast doubt on the viability of FP3 going ahead as planned, with COTA taking the decision to shut the gates to fans until midday on safety grounds.
The FIA decided to go ahead with the session as planned, beginning at 10am CT. Drivers were instructed to only use the full wet tire until told otherwise to aid water clearing on the track and increase grip.
All of the drivers managed to get out for a timed lap early on, knowing that the results from FP3 could be used to form the grid if qualifying is unable to go ahead as planned later today.
The Ferrari duo of Sebastian Vettel and Kimi Raikkonen set the early pace, lapping over 20 seconds slower than usual dry conditions, but times improved as more and more drivers went out and cleared water.
Despite suffering an early spin, Hamilton managed to produce a lap of 1:59.517, handing him P1 on the timesheets as the only driver to get around COTA in less than two minutes.
Vettel finished eight-tenths of a second further back in second place ahead of Nico Hulkenberg and Valtteri Bottas. Carlos Sainz Jr. rounded out the top five for Toro Rosso.
With 30 minutes remaining, the rain grew heavier, prompting the teams to call their drivers back into the pits and stop pushing for quicker lap times.
Many drivers pushed over the limit throughout the session, going off track as a result. Nico Rosberg suffered front wing damage after losing control of his car, while Sebastian Vettel and Max Verstappen also had spins.
Although some did head out for exploratory runs later on, the wet conditions meant that there were no lap time improvements, handing Hamilton P1 and the upper hand if qualifying is indeed cancelled.
Qualifying is due to take place at 1pm CT, but with rain expected to intensify around this time, it is unclear whether or not the session will go ahead.
COTA has now encouraged fans to start making their way to the track, believing that the schedule will be followed as originally planned in spite of the weather.