Video Shows Geyser Erupting at Yellowstone National Park, Tourists Fleeing

Yellowstone National Park tourists were sent scrambling after an unexpected hydrothermal explosion occurred at a geyser there ... which left a destructive scene in the aftermath.

The incident took place Tuesday around the Biscuit Basin area of the park -- which is just over 2 miles away from Old Faithful. Luckily, there were no reports of injuries following the explosion ... however, it caused damage to the sightseeing boardwalk.

Biscuit Basin's parking lot and boardwalks are temporarily closed in order to prioritize visitor safety ... with YNP's geologists currently investigating the event. They say the hydrothermal explosion was not a sign of an impending volcanic eruption ... and said there's been no changes to the Yellowstone region as far as they can tell.

While officials with the United States Geological Survey and Yellowstone described the eruption as small ... a video making the rounds online shows just how harrowing the incident was for tourists -- and yeah, it was absolutely massive ... like a tidal wave of water and ash.

Parkgoers can be seen fleeing down the now-damaged boardwalk as a dark jet of steam skyrockets ... bringing down all sorts of debris, and just barely missing some of them too.