After being dormant since 1972, southern Chile's Calbuco volcano erupted twice in one day on Wednesday. A red alert was issued after the first eruption that occurred at about 6 p.m. local time, according to Al Jazeera. The volcano is located about 1,000 kilometers (625 miles) from Chile's capital city, Santiago.

About 4,000 people had been evacuated from the 20 kilometer radius around the volcano. Chile's Interior Minister Rodrigo Penailillo said the military was being sent to evacuate the people of Llanquihue province, according to Al Jazeera. Water was also being sent, since ash has contaminated the water.

Chilean President Michelle Bachelet is expected to travel to the affected area on Thursday, according to The Huffington Post. No deaths, missing persons or injuries have been reported. Penailillo warned residents to avoid lahars - water and pieces of rock that flow down the sides of the volcano.

The northeast wind has been blowing the mushroom cloud of ash and smoke toward Argentina, according to The Huffington Post.

"In this situation, with the eruption column so high, the main risk is that it collapses, falls due to gravity because of its own weight and causes a pyroclastic flow," Gabriel Orozco, a vulcanologist with Chile's geological and mining service, said on local TV, according to The Huffington Post.

A pyroclastic flow is a superheated flow of gas and rock that travels at 200 to 300 kilometers per hour, destroying everything in its path.

"It sounded like a big tractor trailer passing by the road, rattling and shaking, guttural rumbling. ... We left everything there, grabbed my kid, my dog, got in the car with my wife," said Trevor Moffat, a resident of a town 10 kilometers from the volcano, according to Al Jazeera.

"All the neighbors were outside, a lot of young people crying. Armageddon type reaction," he added, according to The Huffington Post.

Chile is located on the Pacific "Rim of Fire" (or "Ring of Fire") and has the largest chain of volcanoes in the world, second only to Indonesia. Chile has 500 potentially active volcanoes.