Calbuco
This view from Puerto Varas, southern Chile, shows a high column of ash and lava spewing from the Calbuco volcanoDAVID CORTES SEREY / Getty Images stringer

Calbuco volcano unexpectedly erupted on 22 April and then again on 23 April, sending ash and lava kilometres into the skies of southern Chile.

Scientists were not monitoring the volcano in anticipation of the eruption, according to the region's emergency director, and despite Calbuco being one of the country's most active volcanoes, the eruption took experts by surprise.

Calbuco
Smoke and ash rise from the Calbuco volcano as seen from the city of Puerto MonttREUTERS/Rafael Arenas
CAlbuco
View from Frutillar, southern Chile, of lava spewing from the Calbuco volcanoMARTIN BERNETTI / Getty Images

Authorities declared a red alert in the hours before the first eruption and up to 5,000 people have been evacuated from nearby towns, while residents in the Argentinian city of Bariloche, around 100km away, have been ordered to stay indoors.

Some flights in the area have been cancelled and schools have been closed.

Calbuco
Smoke and ash rise from the Calbuco volcano, seen from Puerto Varas city, south of SantiagoREUTERS/Carlos Gutierrez
Calbuco
Smoke and lava spew from the Calbuco volcano, as seen from the shores of Lake Llanquihue in Puerto VarasREUTERS/Carlos Gutierrez

Residents in nearby Puerto Montt, a gateway town to the Patagonia region, wore face masks after the volcano spewed ash over the town.

The town's mayor said residents were very frightened by the unexpected eruption.

Calbuco
A man wears a mask to prevent the harmful effects of the Calbuco volcano ashes, in Puerto VarasMARTIN BERNETTI / Getty Images
Calbuco
View from Puerto Montt, southern Chile, of a high column of ash and lava spewing from the Calbuco volcanoDIEGO MAIN / Getty Images stringer
Calbuco
View from Puerto Montt, southern Chile, of a high column of ash and lava spewing from the Calbuco volcano(DIEGO MAIN /

Calbuco lies around 600 miles south of the Chilean capital Santiago.