The terrifying moment a giant explosion at Yellowstone National Park has been captured by tourists as they ran for their lives.

Biscuit Basin, located just north of Old Faithful, erupted around 10am MST, sending a massive plume of superheated water and debris shooting into the sky.

Vlada March, from California, was visiting the park with her mother and shot the event unfold, showing dozens of visitors swiftly moving off a boardwalk just inches from the hot spring.

The National Park Service has closed all access to Biscuit Basin while geologists investigate the event.

March uploaded the video to Facebook, sharing: 'Biscuit basin at Yellowstone National Park just exploded right in front of us.

'Boardwalk destroyed, my mom got some of the debris but everyone is safe. Unbelievable and grateful to be alive.'

The Californian also shared a clip of the aftermath, revealing the wooden walkway in pieces and the area flooded with water.

The United States Geological Survey (USGS) confirmed a small hydrothermal explosion occurred in the Biscuit Basin thermal area.

This event happens where 'shallow interconnected reservoirs of fluids with temperatures at or near the boiling point underlie thermal fields,' shared USGS.

'These fluids can rapidly transition to steam if the pressure suddenly drops.'

The agency also noted that no injuries have been reported.

The National Park Service said it has not detected any other changes in the Yellowstone region.

'Today’s explosion does not reflect a change in the volcanic system, which remains at normal background levels of activity,' the agency shared in a statement.

USGC echoed the park's statements, saying that 'Hydrothermal explosions like that of today are not a sign of impending volcanic eruptions, and they are not caused by magma rising towards the surface.'

Rangers said they did not know when the boardwalk may reopen.

While the event sparked chaos through the park, Biscuit Basin experienced a previous eruption in May of 2009.