Footage of an extremely powerful hail storm battering a car in Calgary, Alberta, Canada last month.

The video, filmed on June 30, shows the golf ball-sized stones pounding the car windscreen as the driver moves slowly along the highway.

"It started off okay, but when we hit the highway that's when it started getting crazy," the filmer wrote online.

"The hails impact on our car was so loud my brother and I had to yell at each other.

"The road was covered with hail but it looked like snow and many cars pulled over to the side and we did as well.

"We started to drive off again after it started to slow down."