What happens if it rains on the Indy 500?

The 108th running of the Indianapolis 500 is this Sunday, and with a few days to go there is an 80% chance of rain.

For a race to be official drivers must complete 101 laps, just over half of the total 500 mile distance. If they don't make it that far, the race is postponed until the next day without rain.

In the event of rain this year, ticket holders will need to hold on to their tickets. Their ticket will get them back in for the postponement date.

Current forecasts show Wednesday, May 29 as the first dry day after the official race day.

According to Indianapolis Motor Speedway, the Indy 500 has been shortened due to rain eight times in its history, with the shortest official race being 102 laps in 1976.

There have also been times the race was postponed multiple days. In 1973 the race began on Monday, May 28, but a first-lap accident forced the red flag and the race was rained out before it could be restarted. It was postponed again on Tuesday after rain began falling during the second parade lap. The race finally got going on Wednesday, but rain caused it to be stopped and ruled complete after 332.5 miles.

Contact WFYI digital producer and reporter Zach Bundy at zbundy@wfyi.org.