Calbuco volcano in southern Chile erupts.

Calbuco volcano in southern Chile erupts. Image by AP Photo/David Cortes Serey/ Agencia Uno

Twin blasts from the Calbuco volcano in southern Chile have sent vast clouds of ash into the sky, increasing concerns that it could contaminate water, cause respiratory illnesses and ground more flights.

The volcano erupted yesterday afternoon for the first time in more than four decades, and then had another outburst early today. No injuries are reported but one hiker remains missing.

Authorities evacuated 4,000 people as gas and ash continued to spew, and they closed access to the area around the volcano, which lies near the cities of Puerto Varas and Puerto Montt, some 620 miles (1,000km) south of Santiago.

“I was shocked. I had just arrived home when I looked through the window and saw the column of smoke rising up. We called our families, posted photos,” said Daniel Palma, 30, a psychologist who lives in Puerto Varas.

“We woke up today with a blanket of fog and it hasn’t cleared. We have a layer of smoke above us,” Mr Palma added.

Ash cloud from the erupting volcano.

Ash cloud from the erupting volcano. Image by AP Photo/Diego Main/Aton Chile)

President Michelle Bachelet declared a state of emergency, saying the eruption of Calbuco is “more serious and unpredictable” than the one last month at the Villarica volcano, which also forced the evacuation of thousands.

The 6,500ft (2,000m) Calbuco last erupted in 1972 and is considered one of the top three most potentially dangerous among Chile’s 90 active volcanos.

LATAM airlines cancelled flights to and from Puerto Montt because airborne ash can severely damage jet engines.

(Press Association)