Chile Volcano Eruption: Hiker Witnesses Exact Moment Calbuco Erupts

— -- The exact moment Chile's Calbuco volcano erupted was captured on video and uploaded to YouTube by a man hiking in Llanquigue National Reserve, according to the video's description.

The video shows a forest area with gentle waterfalls that appears to be a distance away from the foot of the 6,500-foot-high volcano.

After 28 seconds pass, the volcano erupts, sending a billowing cloud of smoke and ash into the air.

"Wow!" a man can be heard saying in the video, uploaded Thursday.

The video was uploaded by a user under the name Walter Witt. He did not immediately respond to ABC News' message requesting additional comment.

Calbuco erupted twice this week -- once on Wednesday and again on Thursday -- and Chile's national geology and mining service also warned people to prepare for a possible third and "even more aggressive eruption."

Around 4,000 residents in nearby towns were forced to evacuate due to raining ash blanketing their neighborhoods.

This week was the first time the volcano has erupted since 1973, officials said.