Scary moments from the Barber Motorsports Park in Birmingham, Alabama ... where the practice for an IndyCar race resulted in two vicious crashes.

The NTT IndyCar Series' Children's Of Alabama Indy Grand Prix is set to take place Sunday ... but, while driver Scott McClaughlin was practicing Saturday he spun out on the track and careened into a fence.

Check out the clip ... McClaughlin is able to turn the car enough not to go headfirst into the wall -- but still a scary moment for the 32-year-old New Zealander.

Will Power wasn't so lucky while driving the track later in the day ... when instead of making a left like he was supposed to, he went straight into a wall at top speed.

According to reports neither driver was injured ... and, it appears they both plan on driving in the race tomorrow.

Stay safe out there, fellas!