Torrential rain at Phillip Island has wreaked havoc on the first day of practice at the Australian MotoGP and forced a last-minute reshuffle of Saturday's program.
Race organisers announced two schedule options for Saturday - one starting at 9am AEDT and another at 10am - and will wait until 8am before deciding on the best course of action.
However, latest forecasts predict rain will continue to cause chaos.
The first practice session on Friday morning went ahead in light rain, but the second free practice was cancelled as conditions continued to deteriorate.
British rider Cal Crutchlow made the best of tricky conditions during the first practice session to post the quickest time.
But the second session was delayed 40 minutes then halted after just 13 minutes as increasingly heavy rain made conditions treacherous at the exposed coastal circuit.
Race organisers initially planned to restart second practice after a 45-minute pause, but the weather didn't improve, leading to the cancellation of the session and the rest of Friday's program.
The few times recorded in the interrupted second practice were discarded.
First practice got underway in drizzling rain and conditions worsened throughout the 45-minute free practice, with Crutchlow quickest on his LCR Honda.
Nine-time world champion Valentino Rossi finished in second place, but the Italian master was penalised for a tyre violation that dropped him back to 20th.
Local hope Jack Miller was third quickest on his Marc VDS Honda, with newly crowned MotoGP world champion Marc Marquez in fourth.
The only other Australian on the grid, Mike Jones on a Avintia Racing Ducati, was 13th.
In normal circumstances, the top 10 riders on aggregate across three practice sessions go through to second qualifying where they will fight it out for pole position, but Friday's rain means just two sessions will be timed for qualifying.
The remainder of the field will still go into the first qualifying session, with the top two riders there earning entry into second qualifying.
In Moto2 action, Remy Gardner put a week of turmoil behind him to be 10th quickest at the end of first practice.
Gardner's ride on the Tasca Racing Scuderia bike was uncertain after he was detained, with his father Wayne Gardner, by local authorities over an alleged road rage incident before the Japanese grand prix on Sunday.
Remy Gardner arrived in Australia on Thursday, while his father remains in custody and is receiving Australian consular assistance.
German Jonas Golger (Dynavolt Intact GP) was the quickest rider in Moto2 practice, while Brit John McPhee (Peugeot MC Saxoprint) topped the standings in Moto3 practice.
