LOS ANGELES, Aug. 19 (Xinhua) -- An aggressive wildfire burning in state of Montana near the U.S. - Canada border exploded on Saturday, growing from 4,100 acres (16.6 square kilometers) to an estimated 7,800 acres (31.6 square kilometers) and forcing the authority to issue a new evacuation order on Sunday morning.

The fire, dubbed "Howe Ridge fire," was started by a lightning strike on Aug. 11 and has been scorching across the west side of Glacier National Park, a World Heritage site located the border.

The park issued a new release Sunday morning, saying due to the strong wind during the past night, the fire spread very quickly and smoke over the fire perimeter prohibited air resources from dropping water, so the authority has to issue new evacuation order.

Meanwhile, the Montana Department of Environmental Quality issued an air quality alert Sunday for 56 counties, including all of western Montana and the counties surrounding major cities like Helena, Butte and Billings.

Evacuations for some places in the park were in effect last week, so far there is no report of casualty, but a harrowing video posted online Saturday showing a father and son made a mad trip in the middle of a blazing forest fire while driving down a winding mountain road in the park was clicked by tens of thousands times in one day.

Justin Bilton explained on YouTube in sharing the video that he and his 70-year-old father were forced to flee the campground according to an evacuation order earlier, but they were stuck at a trailhead at the end of a dead-end road.

In the video, Bilton repeatedly worry they aren't going to make it out with their lives, asking, "What if the car blows up?" and eventually saying, "Dad this is insane."

The pair were rescued by two park rangers after abandoning their vehicle.