Fernando Alonso qualified seventh at Indianapolis on a day compromised by the weather and a horrific accident involving former F1 driver Sebastien Bourdais.

After misty conditions caused a brief hold-up to the morning's practice session, the oval was opened to the 33-car field, where a handful of cars, including Gabby Chaves and Graham Rahal completed just 51 laps.

Rain began falling at the track just as first-day qualifying was scheduled to begin at 11:00. Heavy rain and lightning persisted until after 13:00. Safety trucks started circulating the oval at 13:30 as the track-drying process began. Shortly before 15:30, organisers announced that qualification would begin at 16:01, with each entry being permitted one attempt at the four-lap qualification run to set the groups for Sunday's second day of qualifying.

IMS president Doug Boles subsequently announced that the track would remain open past its normal 18:00 closing time to allow all entries one four-lap attempt once the track is open for qualifying.

Drivers took their turn in the order designated by Friday's draw - Alonso having drawn 15 - at the four-lap qualification run in an attempt to qualify for next Sunday's race, as well as to position themselves in the Fast Nine Shootout to give themselves a shot at pole position for the 101st Indianapolis 500.

Alonso made quite an impression in his first qualifying run for the 500, as his four-lap average of 230.034 mph placed him provisionally in the top three.

Fast Friday's fastest driver Sebastien Bourdais posted the two fastest laps of the day before losing control in Turn 2 on his third lap and making heavy contact with the barrier.

The four-time IndyCar champion did not lose consciousness in the incident, and was awake and alert when the safety team arrived. After visiting the IU Health Emergency Medical Center, the Frenchman was taken to IU Health Methodist Hospital for further observation.

Bourdais was diagnosed with multiple fractures to his pelvis and a fracture to his right hip and according to IndyCar Medical Director Dr. Geoffrey Billows, Bourdais will undergo surgery on his pelvis.

"Sebastien is in good hands here at IU Methodist Hospital with the staff and now we just wait for him to recover," said team owner Dale Coyne.

Meanwhile, by the end of the session, Alonso had dropped to seventh - behind Ed Carpenter, Takuma Sato, Scott Dixon, JR Hildebrand, Alexander Rossi and Will Power - and will compete in today's Fast Nine Shootout which ultimately decides pole position and the first three rows for next Sunday's race.

"It gets stressful, it gets difficult, tricky," said Alonso. "But at the same time, there's huge adrenaline when you cross the line (to conclude the run).

"Today was all about being in the fast nine. We did it and tomorrow is the real thing, so let's see.

"It has been a fantastic week of running," he added, "a fantastic week of different experiences, running alone, high boost, low boost; every lap feels different.

"Today we only had one attempt because of the weather, so that creates stress in everybody, but I think we deal with that today. But as I said, I think there will be more speed to come, hopefully, tomorrow."

The Fast Nine Shootout runs from 17:00 - 17:45 (local time), and with the times from first-day qualifying erased, each of the nine drivers - the remaining two being Tony Kanaan and Marco Andretti - make a four-lap attempt in the reverse order of where they finished on Saturday.