Torrential rain and electrical storms led to the cancellation of Friday afternoon’s second free practice session for this weekend’s United States Grand Prix.

The session was initially postponed indefinitely because marshals at the Circuit of the Americas were unable to work due to the close proximity of the lightning.

Hopes of starting the session later were then dashed when it was confirmed that practice had been abandoned because the circuit’s medical helicopter would not be allowed to take off for at least two hours due to the conditions.

“@F1@circuitamericas looks like my boat licence may help today….,” tweeted Lotus’s French driver Romain Grosjean.

The opening free practice session, in the morning, was also hampered by rain and run in damp conditions with Nico Rosberg setting the pace.

The German driver made a determined first move towards wrecking Mercedes teammate Lewis Hamilton’s title party.

The 30-year-old Rosberg, who has to prevent Hamilton beating him by three points in Sunday’s race to keep his own challenge alive, clocked a best lap of one minute and 53.989 seconds on a damp, drying track.

Hamilton, feeling his way cautiously, was one of the majority of drivers who were slow to join the fray and wound up fifth quickest after a relatively desultory session in poor conditions.

Heavy rain had soaked the circuit ahead of the action and had been forecast for the rest of the weekend, a factor that may play havoc with the outcome as defending double world champion Hamilton bids to wrap up his third title three races remaining.

Rosberg’s best time left him more than 1.2 seconds clear of the Red Bull pairing of Daniil Kvyat and Daniel Ricciardo with Carlos Sainz fourth for Toro Rosso.

Four-time champion Sebastian Vettel, who is second behind Hamilton in the title race, was sixth for Ferrari after clocking only 10 laps in the session.

Vettel has already been handicapped ahead of Sunday’s race by being hit with a 10-place grid penalty after Ferrari introduced new engines for the event.