The footage shows Mark pull over when he spots a downed tree across the road and a car on the opposite side that appeared to have been damaged by running over the tree.
Mark briefly speaks to a woman standing outside the car before a semi truck appears in the road ahead.
The semi appears to attempt to avoid the tree, but ends up losing control, running over the plant and narrowly missing Mark's truck by a matter of inches.
The woman can be heard shouting that she was also able to avoid being hit by the truck.
The video's description calls the incident "a true brown pants moment."
The woman, who identified herself as Helen, told 9News the truck destroyed her car, but she was able to dive out of the way.
"I'm about to be killed. That's what went through my head," Helen said. "I honestly don't know how close it got to me, I just ran."
Helen praised the truck driver, saying the incident could have been far worse.
"He didn't do anything wrong, the log was across the road, you couldn't avoid the log," she said.
